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Title: Full C language
Description: All detailed notes of C language with programs and examples
Description: All detailed notes of C language with programs and examples
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HI - TECH COMPUTERS
C Programming
The C Language is developed by Dennis Ritchie for creating
system applications that directly interact with the hardware
devices such as drivers, kernels, etc
...
Mother language
TE
CH
It can be defined by the following ways:
System programming language
Procedure-oriented programming language
Structured programming language
Mid-level programming language
1) C as a mother language
C language is considered as the mother language of all the
modern programming languages because most of the compilers,
JVMs, Kernels, etc
...
It
provides
-
programming languages follow C syntax, for example, C++, Java,
the
core
concepts
like
the
array,
strings,
functions, file handling, etc
...
2) C as a system programming language
A
system
programming
language
is
used
to
create
system
software
...
It is generally used to create hardware devices,
OS,
drivers,
kernels,
etc
...
It can't be used for internet programming like Java,
...
C - LANGUAGE
1
HI - TECH COMPUTERS
3) C as a procedural language
A
procedure
is
known
as
a
function,
method,
routine,
subroutine, etc
...
A procedural language breaks the program into functions, data
structures, etc
...
In
C,
variables
and
function
prototypes must be declared before being used
...
Structure means to break a program into
parts or blocks so that it may be easy to understand
...
It
makes
modify
...
C
-
language program is converted into assembly code, it supports
pointer arithmetic (low-level), but it is machine independent
(a feature of high-level)
...
e
...
It is machine dependent, fast to run
...
A High-Level language is not specific to one machine, i
...
,
machine independent
...
C Program
#include
S
...
Dennis Ritchie is known as the founder of the c language
...
operating
C
language
system
...
Let's see the programming languages that were developed before
C language
...
It provides many features that
are given below
...
Simple
2
...
Mid-level programming language
4
...
Memory Management
7
...
Pointers
9
...
Extensible
1) Simple
C
is
a
simple
language
TE
CH
5
...
Unlike
-
2) Machine Independent or Portable
assembly
different
language,
machines
with
c
programs
some
machine
can
be
executed
specific
on
changes
...
HI
3) Mid-level programming language
Although, C is intended to do low-level programming
...
It also supports the features of a high-level language
...
4) Structured programming language
C is a structured programming language in the sense that we
can break the program into parts using functions
...
Functions also provide code
reusability
...
6) Memory Management
It supports the feature of dynamic memory allocation
...
7) Speed
there
are
lesser
TE
CH
The compilation and execution time of C language is fast since
inbuilt
overhead
...
We can directly interact
with the memory by using the pointers
...
9) Recursion
In
C,
we
provides
can
code
call
the
function
reusability
for
within
every
the
function
...
It
Recursion
10) Extensible
C
language
-
enables us to use the approach of backtracking
...
First C Program
Before starting the abcd of C language, you need to learn how
to write, compile and run the first c program
...
h>
int main(){
printf("Hello C Language");
return 0;
}
C - LANGUAGE
5
HI - TECH COMPUTERS
#include
The printf() function is defined in stdio
...
int main() The main() function is the entry point of every
program in c language
...
return 0 The return 0 statement, returns execution status to
unsuccessful execution
...
The 0 value is used for successful execution and 1 for
How to compile and run the c program
By menu
Now click on the compile menu then compile sub menu to compile
the c program
...
By shortcut
Or, press ctrl+f9 keys compile and run the program directly
...
-
c program output
You can view the user screen any time by pressing the alt+f5
keys
...
What is a compilation?
The compilation is a process of converting the source code
into object code
...
The compiler checks the source code for the syntactical or
structural errors, and if the source code is error-free, then
it generates the object code
...
The compilation
process can be divided into four steps, i
...
, Pre-processing,
Compiling, Assembling, and Linking
...
The
preprocessor takes the preprocessor directive and interprets
it
...
h>, the directive is available in
the program, then the preprocessor interprets the directive
and replace this directive with the content of the 'stdio
...
TE
CH
The following are the phases through which our program passes
before being transformed into an executable form:
● Preprocessor
● Compiler
● Assembler
● Linker
Preprocessor
The source code is the code which is written in a text editor
and the source code file is given an extension "
...
This
source code is first passed to the preprocessor, and then the
-
preprocessor expands this code
...
Compiler
The code which is expanded by the preprocessor is passed to
HI
the compiler
...
Or
we
can
say
that
the
C
compiler
converts
the
pre-processed code into assembly code
...
The
name
of
the
object
file
generated
by
the
assembler is the same as the source file
...
obj,' and in UNIX, the extension is
'o'
...
c', then the
name of the object file would be 'hello
...
C - LANGUAGE
7
HI - TECH COMPUTERS
Linker
Mainly, all the programs written in C use library functions
...
lib'
(or
'
...
The main working of the linker is to combine the
object
code
program
...
It links the object code
of these files to our program
...
The
output of the linker is the executable file
...
In
DOS,
the
extension
of
the
executable file is '
...
out'
...
Let's understand through an example
...
c
HI
1
...
h>
2
...
{
4
...
return 0;
6
...
e
...
c, is passed to the
preprocessor,
code
into
and
the preprocessor converts the source
expanded
source
code
...
i
...
The extension of the assembly code would
be hello
...
TE
CH
● This assembly code is then sent to the assembler, which
converts the assembly code into object code
...
The
loader
will
then
load
the
executable file for the execution
...
Both functions are inbuilt library
functions, defined in stdio
...
-
printf() function
The printf() function is used for output
...
The syntax of printf() function is given below:
HI
printf("format string",argument_list);
The
format
string
can be %d (integer), %c (character), %s
(string), %f (float) etc
...
It reads the input
data from the console
...
C - LANGUAGE
9
HI - TECH COMPUTERS
#include
The
printf("cube
of
number
is:%d
",number*number*number)
statement prints the cube of number on the console
...
#include
It is used to
many times
...
Its value can be changed, and it can be reused
It is a way to represent memory location through symbol so
that it can be easily identified
...
The int, float, char are the data
types
...
8;
char c='A';
Rules for defining variables
A variable can have alphabets, digits, and underscore
...
It can't start with a digit
...
C - LANGUAGE
11
HI - TECH COMPUTERS
A variable name must not be any reserved word or keyword, e
...
int, float, etc
...
It must be declared at the start of the block
...
C - LANGUAGE
12
HI - TECH COMPUTERS
Global Variable
A variable that is declared outside the function or block is
called a global variable
...
It is available to all the functions
...
int value=20;//global variable
int x=10;//local variable
}
Static Variable
TE
CH
void function1(){
A variable that is declared with the static keyword is called
static variable
...
void function1(){
int x=10;//local variable
-
static int y=10;//static variable
x=x+1;
y=y+1;
printf("%d,%d",x,y);
HI
}
If you call this function many times, the local variable will
print the same value for each function call, e
...
But
the static variable will print the incremented
value in each function call, e
...
11, 12, 13 and so on
...
We can explicitly declare an
automatic variable using auto keyword
...
TE
CH
external variable
...
c
#include "myfile
...
h>
void printValue(){
printf("Global variable: %d", global_variable);
}
-
Data Types in C
A data type specifies the type of data that a variable can
store such as integer, floating, character, etc
...
Data Types
Basic Data Type
int, char, float, double
Derived Data Type
array, pointer, structure, union
Enumeration Data Type
enum
Void Data Type
void
HI
Types
C - LANGUAGE
14
HI - TECH COMPUTERS
Basic Data Types
The
basic
data
types
are
integer-based
and
floating-point
based
...
The memory size of the basic data types may change according
to 32 or 64-bit operating system
...
Its size is given according to
32-bit architecture
...
You cannot use it as a variable
name, constant name, etc
...
break
case
char
const
continue
default
do
double
else
enum
extern
float
for
goto
if
int
long
register
return
short
signed
sizeof
static
struct
switch
typedef
union
unsigned
void
volatile
while
HI
auto
-
A list of 32 keywords in the c language is given below:
C - LANGUAGE
16
HI - TECH COMPUTERS
C Identifiers
C
identifiers
example,
represent
variables,
the
name
functions,
in
the
arrays,
C
program,
structures,
for
unions,
labels, etc
...
If the identifier is not used in the external linkage, then it
is called as an internal identifier
...
We can say that an identifier is a collection of alphanumeric
characters that begins either with an alphabetical character
or
an
underscore,
programming
elements
structures,
unions,
characters
which
such
are
as
labels,
(uppercase
and
used
to
represent
various
variables,
functions,
arrays,
etc
...
is
a
total
of
63
alphanumerical
characters
-
There
represent the identifiers
...
is
simply
There
can
a
symbol
that
is
be
many
types
of
used
to
perform
operations
like
arithmetic, logical, bitwise, etc
...
● Arithmetic Operators
● Shift Operators
● Logical Operators
● Bitwise Operators
TE
CH
● Relational Operators
● Ternary or Conditional Operators
● Assignment Operator
Precedence of Operators in C
The precedence of operator species that which operator will be
evaluated
first
and
next
...
-
operator direction to be evaluated; it may be left to right or
Let's understand the precedence by the example given below:
1
...
The
precedence
and
associativity
of
C
operators
is
below:
C - LANGUAGE
18
given
HI - TECH COMPUTERS
Category
Operator
Associativity
Postfix
() [] ->
...
, on the given operands
...
are the
examples of arithmetic operators
...
(+)
Operator
used
to
add
two
given
operands
...
Syntax
C = A + B;
For example, there are two operands, 5 and 6, and we want to
the
sum
of
these
numbers
...
#include
h>
int main ()
{
// declare integer variables
int num1, num2, res;
// declare float data type number
float f1, f2, res1;
// declare double variables
double d1, d2, res2;
printf (" Enter two integer numbers: ");
scanf ("%d %d", &num1, &num2);
res = num1 + num2; // use + operator
C - LANGUAGE
20
HI - TECH COMPUTERS
printf (" Enter two float numbers: \n ");
scanf ("%f %f", &f1, &f2);
res1 = f1 + f2; // use + operator
printf (" Enter two double data type numbers: \n ");
scanf ("%lf %lf", &d1, &d2);
res2 = d1 + d2; // use + operator
TE
CH
printf (" The sum of two integer numbers: %d \n", res);
printf (" The sum of two float numbers: %f \n ", res1);
printf (" The sum of two double numbers: %lf", res2);
return 0;
}
Output
Enter two integer numbers: 25
35
Enter two float numbers:
79
...
79
Enter two double data type numbers:
234
...
341
The sum of two integer numbers: 60
The sum of two float numbers: 147
...
464000
Minus Operator
The minus operator is denoted by the minus (-) symbol
...
different
The
types,
data
such
as
type
int,
of
the
float,
given
number
double,
long
can
double,
etc
...
C - LANGUAGE
be
21
HI - TECH COMPUTERS
Syntax
C = A - B;
For example, there are two operands, 15 and 6, and we want
their subtraction result
...
/* program to subtract the two numbers using minus operator */
#include
h>
// declare integer variables
int num1, num2, res;
// declare float data type number
float f1, f2, res1;
// declare double variables
double d1, d2, res2;
printf (" Enter two integer numbers: ");
-
scanf ("%d %d", &num1, &num2);
res = num1 - num2; // use + operator
printf (" Enter two float numbers: \n ");
HI
scanf ("%f %f", &f1, &f2);
res1 = f1 - f2; // use + operator
printf (" Enter two double data type numbers: \n ");
scanf ("%lf %lf", &d1, &d2);
res2 = d1 - d2; // use + operator
printf
("
The
subtraction of two integer numbers: %d \n",
("
The
subtraction
res);
printf
of
two
float
numbers: %f \n ",
res1);
printf (" The subtraction of two double numbers: %lf", res2);
return 0;
}
C - LANGUAGE
22
HI - TECH COMPUTERS
Output
Enter two integer numbers: 56
11
Enter two float numbers:
78
...
45
Enter two double data type numbers:
1234
...
7149
The subtraction of two integer numbers: 45
The subtraction of two float numbers: 22
...
916200
Multiplication Operator
The multiplication operator is represented as an asterisk (*)
symbol, and it is used to return the product of n1 and n2
numbers
...
C = A * B;
HI
For example, there are two operands 15 and 6, and we want to
get their product
...
/* program to multiply two numbers using astrisk (*) operator
...
h>
#include
5
3
...
324
798
...
750000
C - LANGUAGE
24
%lf",
HI - TECH COMPUTERS
The multiplication of two double numbers: 187019
...
Using
division
operator (/), we can divide the int, float, double and long
Syntax
C = A / B;
TE
CH
data types variables
...
5 and 5
...
So, we use the '/' Operator
between the given numbers that return float data 5
...
/* program to divide the first number by second number using
division (/) operator
...
h>
#include
32
248
...
7691
687
...
862247
The division of two double numbers: 6
...
Syntax
C = A % B;
For example, there are two operands 25 and 4, and we want to
get
their
modulus
result
...
/*
program
to
return
the
remainder
of
two
numbers
modulus (%) operator
...
h>
#include
It
is
used
A
is
10,
to
increase the integer value by 1
...
C - LANGUAGE
27
HI - TECH COMPUTERS
/* program to demonstrate the increment (++) operator
...
h>
#include
Syntax
B = A--;
For
example,
decrement
suppose
operator
the
integer
decreases
the
value
operand
of
A
value
is
by
10,
the
1
that
returns 9
...
*/
#include
h>
int main ()
C - LANGUAGE
28
HI - TECH COMPUTERS
{
// declare integer variables
int num1, res;
printf (" Enter the positive number: ");
scanf ("%d", &num1);
res = num1--; // use decrement operator
printf (" The decremented value is: %d ", num1);
TE
CH
return 0;
}
Output
Enter the positive number: 10
HI
-
The decremented value is: 9
C - LANGUAGE
29
HI - TECH COMPUTERS
Relational Operator in C
Relational
Operators
are
the
operators
used
to
create
a
relationship and compare the values of two operands
...
Equal To Operator (==)
TE
CH
Types of Relational Operators
It is used to compare both operands and returns 1 if both are
equal or the same, and 0 represents the operands that are not
equal
...
#include
h>
int main ()
HI
{
int a = 5;
int b = 10;
// Use Equal To Operator
printf (" a == b : %d", (a == b));
if (a == b)
printf ("\n %d is equal to %d", a, b);
else
printf (" \n %d is not equal to %d", a, b);
C - LANGUAGE
30
HI - TECH COMPUTERS
int x = 5;
int y = 5;
// Use Equal To Operator
printf (" \n x == y : %d", (x == y));
if (a == b)
printf (" \n %d is equal to %d", x, y);
else
return 0;
}
Output
a == b : 0
5 is not equal to 10
x == y : 1
5 is not equal to 5
TE
CH
printf ("\n %d is not equal to %d", x, y);
-
Not Equal To Operator (!=)
The Not Equal To Operator is the opposite of the Equal To
Operator
and
is
represented as the (!=) operator
...
Syntax:
Opr1 != Opr2;
Let's create a simple program to use the Not equal to (!=)
operator for comparing the values of variable in C
...
h>
#include
C - LANGUAGE
32
HI - TECH COMPUTERS
Syntax:
A < B;
Here the operand A is less than operand B
...
h>
int main ()
{
int num1, num2;
TE
CH
compare the operand value in C
...
");
HI
}
else
{
printf (" \n The value of num2 is less than num1
...
C - LANGUAGE
33
HI - TECH COMPUTERS
Greater than Operator (>)
The operator checks the value of the left operand is greater
than the right operand, and if the statement is true, the
operator is said to be the Greater Than Operator
...
Let's create a program to use the greater than operator (>) to
compare the operand value in C
...
h>
int main ()
{
int num1, num2;
printf (" Enter the value of num1: ");
-
scanf (" %d", &num1);
printf (" \n Enter the value of num2: ");
scanf (" %d", &num2);
HI
// use greater than operator (>)
if (num1 > num2)
{
printf (" \n The value of num1 is greater than num2
...
");
}
return 0;
}
C - LANGUAGE
34
HI - TECH COMPUTERS
Output
Enter the value of num1: 20
Enter the value of num2: 30
The value of num2 is greater than num1
...
Syntax:
A <= B;
Here, operand A is less than or equal to operand B
...
Let's create a program to use the Less than Equal to operator
-
(<=) to compare the operand value in C
...
h>
int main ()
{
HI
int num1, num2;
printf (" Enter the value of num1: ");
scanf (" %d", &num1);
printf (" \n Enter the value of num2: ");
scanf (" %d", &num2);
// use less than equal to operator (<=)
if (num1 < num2)
{
printf (" \n The value of num1 is less than num2
...
");
}
else
{
printf (" \n The value of num2 is less than num1
...
Greater than Equal To Operator (>=)
The
operator
checks
whether
the
left
operand's
value
is
greater than or equal to the right operand
...
-
is true, the operator is said to be the Greater than Equal to
Syntax:
HI
A >= B;
Here, operand A is greater than equal to the right operand B
...
Let's
create
a
program
to
use
the
Greater
than
Equal
operator to compare the operand value in C
...
h>
int main ()
{
int num1, num2;
printf (" Enter the value of num1: ");
C - LANGUAGE
36
To
HI - TECH COMPUTERS
scanf (" %d", &num1);
printf (" \n Enter the value of num2: ");
scanf (" %d", &num2);
// use greater than equal to operator (>=)
if (num1 > num2)
{
TE
CH
printf (" \n The value of num1 is greater than num2
...
");
}
else
{
printf (" \n The value of num2 is greater than num1
...
C - LANGUAGE
37
HI - TECH COMPUTERS
Assignment Operator in C
There
are
different
kinds
of
the
operators,
such
as
arithmetic, relational, bitwise, assignment, etc
...
The
assignment
operator
is
used
to
assign the value, variable and function to another variable
...
TE
CH
Example of the Assignment Operators:
A = 5; // use Assignment symbol to assign 5 to the operand A
B = A; // Assign operand A to the B
B = &A; // Assign the address of operand A to the variable B
A = 20 \ 10 * 2 + 5; // assign equation to the variable A
Assignment Operator in C
Simple Assignment Operator (=):
It is the operator used to assign the right side operand or
Syntax
-
variable to the left side variable
...
Program1
...
h>
#include
Syntax
HI
A += B;
Or
A = A + B;
Let's create a program to use the Plus and assign operator in
C
...
c
#include
h>
int main ()
{
// initialize variables
C - LANGUAGE
39
HI - TECH COMPUTERS
int n1, n2, c;
n1 = 5;
n2 = 10;
n2 += n1;
printf (" \n The value of n1: %d", n1);
printf (" \n The value of n2: %d", n2);
}
Output
The value of a: 5
The value of b: 15
TE
CH
return 0;
Subtract and Assign Operator (-=):
The operator is used to subtract the left operand with the
right operand and then assigns the result to the left operand
...
Program3
...
h>
#include
Syntax
A *= B;
Or
A = A * B;
Let's create a program to use the multiply and assign operator
-
(*=) in C
...
h>
#include
Syntax
A /= B;
Or
A = A / B;
Let's create a program to use the divide and assign operator
(/=) in C
...
c
-
#include
h>
int main ()
{
HI
// initialize variables
int n1, n2, c;
n1 = 5;
n2 = 10;
n2 /= n1; // Use divide and Equal operator (b = b / a)
printf (" \n The value of n1: %d", n1);
printf (" \n The value of n2: %d", n2);
return 0;
}
Output
The value of n1: 5
The value of n2: 2
C - LANGUAGE
42
HI - TECH COMPUTERS
Modulus and Assign Operator (%=):
An
operator
used
between
the
left
operand
and
the
right
operand divides the first number (n1) by the second number
(n2) and returns the remainder in the left operand
...
#include
h>
int main ()
{
// initialize variables
-
int n1, n2, c;
printf (" Enter the value of n1: ");
HI
scanf ("%d", &n1);
printf (" \n Enter the value of n2: ");
scanf ("%d", &n2);
n1 %= n2; // Use modulus and Equal operator (a = a % b)
printf (" \n The modulus value of n1: %d", n1);
return 0;
}
Output
Enter the value of n1: 23
Enter the value of n2: 5
The modulus value of n2: 3
C - LANGUAGE
43
HI - TECH COMPUTERS
Pre-increment and Post-increment Operator in C
Increment
operators
are
the
operator
of
the
C
programming
language used to increase the given variable's value by 1
...
On the other hand, the increment
operator can increase the given value by 1 after assigning the
TE
CH
variable
...
Pre-increment and Post-increment Operator in C
Properties of the Increment operator
There
are
some
properties
follows:
of
the
increment
operator,
as
The increment operator is used to increase the current value
of the variable by 1
...
It is the operator represented by the double plus (++) symbol
...
The
pre-increment operator is used to increment the value of an
operand by 1 before using it in the mathematical expression
...
Syntax
x = ++a;
C - LANGUAGE
44
HI - TECH COMPUTERS
In
the
above
syntax,
the
value
of
variable
'a'
is
first
incremented by 1 before using in the expression
...
#include
h>
int main ()
TE
CH
{
// declaration of the variables
int a = 7;
int b = 2
// print the value of the increment operator
printf (" Use the pre-increment operator " );
printf (" The value of a is %d ", a);
printf (" The value of b is %d ", b);
// use pre-increment operator
-
b = ++a;
printf (" After using the pre-increment operator ");
printf (" The value of a is %d ", a);
printf (" The value of b is %d ", b);
HI
return 0;
}
Output
Use the pre-increment operator
The value of a is 7
The value of b is 2
After using the pre-increment operator
The value of a is 8
The value of b is 10
C - LANGUAGE
45
the
HI - TECH COMPUTERS
Example
2:
Let's
create
another
program
to
use
the
pre-increment operator in mathematical expression
...
c
#include
h>
int main ()
{
int a, b, c, d, x;
TE
CH
// declare integer variables
// initialization of the variables
a = 5;
b = 7;
c = 12;
d = 15;
//
use
pre-increment
operator
in
the
mathematical
expression
-
x = ++a + ++b + ++c + ++d;
printf( " The value of x is: %d ", x);
// print the updated value of a, b, c, and d
HI
printf (" \n The updated value of a = %d, b = %d, c = %d and d
= %d ", a, b, c, d);
return 0;
}
Output
The value of x is: 43
The updated value of a = 6, b = 8, c = 13 and d = 16
C - LANGUAGE
46
HI - TECH COMPUTERS
Post-increment Operator
Post-increment is an increment operator, represented as the
double
plus
(a++)
symbol
followed
by
an
operator
'a'
...
In
other
words,
the
variable's
original value is used in the expression first, and then the
Syntax
x = a++;
TE
CH
post-increment operator updates the operand value by 1
...
Example
1:
Let's
create
a
simple
program
to
use
post-increment operator in C programming language
...
c
-
#include
h>
int main ()
{
HI
// declaration of the variables
int a = 7;
int b = 0;
// print the value of the increment operator
printf (" Before using the post-increment operator " );
printf (" \n The value of a is %d ", a);
printf (" \n The value of b is %d ", b);
// use post increment operator
b = a++;
printf (" \n\n After using the post-increment operator ");
printf (" \n The value of a is %d ", a);
C - LANGUAGE
47
the
HI - TECH COMPUTERS
printf (" \n The value of b is %d ", b);
return 0;
}
Output
Before using the post-increment operator
The value of a is 7
The value of b is 0
The value of a is 8
The value of b is 7
Example
2:
Let's
TE
CH
After using the post-increment operator
create
another
program
to
use
the
post-increment operator in mathematical expression
...
h>
#include
#include
h>
int main ()
{
int x, y, z, exp;
-
printf (" Enter the value of x: ");
scanf (" %d", &x);
printf (" \n Enter the value of y: ");
scanf (" %d", &y);
HI
printf (" \n Enter the value of z: ");
scanf (" %d", &z);
printf (" \n Before using the increment operator: ");
printf (" \n The original value of x: %d", x);
printf (" \n The original value of x: %d", y);
printf (" \n The original value of x: %d", z);
// use pre-increment and post-increment operator
exp = x++ + ++x + ++y + y++ + ++z;
printf (" \n\n After using the increment operator: ");
printf (" \n The result of the expression is: %d", exp);
printf (" \n The updated value of x: %d", x);
C - LANGUAGE
49
HI - TECH COMPUTERS
printf (" \n The updated value of y: %d", y);
printf (" \n The updated value of z: %d", z);
return 0;
}
Output
Enter the value of y: 12
Enter the value of z: 15
TE
CH
Enter the value of x: 7
Before using the increment operator:
The original value of x: 7
The original value of x: 12
The original value of x: 15
After using the increment operator:
The result of the expression is: 58
-
The updated value of x: 9
The updated value of y: 14
HI
The updated value of z: 16
C - LANGUAGE
50
HI - TECH COMPUTERS
Unary Operator in C
In this section, we will discuss the unary operator in the C
programming language
...
A unary operator is an operator used to operate on a single
to
return
a
new
value
...
In
Unary
Operator, operators have equal priority from right to left
side associativity
...
Unary Minus (-)
Unary Plus (+)
Increment (++)
HI
Decrement (--)
Logical Negation (!)
Address Operator (&)
Sizeof() operator
Unary Minus (-)
The Unary Minus operator is represented using the symbol (-)
...
It means it changes the positive
number
to
the
negative, and a negative number becomes the
positive number using the unary minus operator
...
h>
#include
int b = -(a); // use unary minus operator to change the value
int n1 = 20;
int n2 = -30;
printf (" The value of a: %d \n", a);
printf (" The value of b: %d \n", b);
-
printf (" The value of -n1: %d \n", -n1);
printf (" The value of -n2: %d ", -n2);
return 0;
HI
}
Output
The value of a: 5
The value of b: -5
The value of -n1: -20
The value of -n2: 30
C - LANGUAGE
52
HI - TECH COMPUTERS
Unary plus (+)
The unary plus operator is represented as the "+" symbol, and
it does not change to the operand value
...
h>
#include
The "++" symbol represents the operand's value is
by
1
...
Pre Increment: The pre-increment operator is represented as
(++a), which means the value of variable 'a' is increment by 1
before using operand to the expression
...
Post Increment: The (a++) symbol represents the post-increment
operator, which means the value of 'a' is incremented by 1
after
assigning
the
original
value
to
the
expression
or
For example:
x = 10;
A = x++;
TE
CH
another variable
...
#include
h>
-
int main ()
{
int x, y, a, b; // declare local variable
a = 10;
HI
x = ++a; // It shows pre increment operator
printf (" Pre Increment Operator");
// Here the value of x is increased by 1
...
", x);
printf (" \n The value of a is %d
...
", y);
C - LANGUAGE
54
HI - TECH COMPUTERS
// get updated value of b
printf (" \n The value of b is %d
...
The value of a is 11
...
The value of b is 21
...
The
is
Unary
opposite
decrement
to
the
unary
operator
is
-
represented by the double minus (--) symbol, and it is used to
decrease the operand value by 1 according to the decrement's
types
...
HI
Pre Decrement: The pre decrement operator is denoted as (--a)
symbol, meaning the operand value is decreased by 1 before
assigning to another variable or expression
...
C - LANGUAGE
55
HI - TECH COMPUTERS
Syntax
int post = a--;
#include
h>
int main ()
{
int x, y, a, b; // declare local variable
TE
CH
a = 10;
x = --a; // It shows pre decrement operator
printf (" Pre Decrement Operator");
// Here the value of x is decreased by 1
...
", x);
printf (" \n The value of a is %d
...
", y);
// get updated value of b
HI
printf (" \n The value of b is %d
...
The value of a is 9
...
C - LANGUAGE
56
HI - TECH COMPUTERS
The value of b is 19
...
Syntax
TE
CH
sizeof(data_variable);
#include
h>
int main ()
{
// declaration of different types of data variables
int x;
float y;
char ch;
//
use
-
double z;
sizeof()
operator and pass the different data type
variable to get their size
...
For example, if the operand is true, the logical
not operator (!) reverses and return false; if the operand is
false, the logical operator returns true
...
h>
int main ()
{
-
#include
Syntax
int a = 5;
int b = &a; // variable b hold the address of variable a
Example 7:
#include
h>
-
int main ()
{
// declare variables
int a = 10;
HI
int b;
// use addressof (&) operator to assign the address
b = &a;
printf (" The value of variable a is: %d", a);
printf (" \n The address of variable b is: %d", b);
return 0;
}
Output
The value of variable a is: 10
The address of variable b is: 6487704
C - LANGUAGE
(&)
variable
TE
CH
The
59
HI - TECH COMPUTERS
Logical operators
An
operator
can
be
performing
different
there
various
are
defined
as
a
symbol
that
is
used for
operations
...
TE
CH
In this article, we are discussing the logical operators and
their types, along with an example of each
...
Some
irrespective
programming
of
a
languages
support limited operators, so some of the logical operators
that we are discussing may or may not be supported by the
programming language you are using
...
They return Boolean values
...
These
operators
-
make
allow
the
evaluation
and
manipulation of specific bits within the integer
...
||
This operator returns true if at least one of the
(Logical
relational statements combined with || is true,
OR)
else it returns false
...
HI
Operators
operator
returns
true
if
all
relational
NOT)
C - LANGUAGE
60
HI - TECH COMPUTERS
&& (Logical AND)
The logical && operator doesn't check the second condition if
first condition is false
...
The
evaluation
in
logical
&&
expression is left to right
...
This
TE
CH
operators,
operator accepts two operands
...
So, we can see the
possible values of A && B in the below table
...
Here, we are discussing the four cases to show the possible
conditions of && operator and also to check the result where
it returns false or where it returns true
...
the
Programmers
parentheses
often
use
as
it
it
is
not
to
make
technically
the
logic
of
expression very clear
...
10 > 20 && 20 > 5
Statement 1 in the above line is 10 > 20 and statement 2 is 20
> 5
...
AND operator will give
the true value only when both statements are true
...
Case 2:
1
...
Statement 1 in the above line is true, so in this case, the
operator
will
further
check
the
second
statement,
but
the
false as a result
...
10 > 20 && 20 < 5
TE
CH
second statement is false so, the operator will give us the
In this case, both statements are false
...
Although it is similar to the
first case, the operator will not check the second statement
because the first statement is not true
...
10 < 20 && 20 > 5
-
In this case, we can see both statements are true, so the
HI
operator will give us the true as a result
...
It works opposite to the logical AND operator,
as it only gives false when both statements of the expression
are not true
...
The logical || operator doesn't check the second condition if
first condition is true
...
TE
CH
The logical || operator accepts two operands
...
We can see the possible values of A ||
B in the following table
...
Here, we are discussing the four cases to show the possible
conditions of || operator and also to check the result where
it returns false or where it returns true
...
10 < 20 || 20 < 5
Statement 1 in the above line is 10 < 20 and statement 2 is 20
< 5
...
As stated earlier, OR operator will
give
the
true
value
when
one
of
the
statements
of
expression is true
...
10 > 20 || 20 > 5
In this case, operator will again return true as a result
...
Case 3:
1
...
The first statement is true, and
after
checking
it,
the operator will not check the second
statement and gives us the true as a result
...
10 < 20 || 20 < 5
Here, both of the statements are false
...
C - LANGUAGE
64
HI - TECH COMPUTERS
! (Logical NOT operator)
This logical operator is represented as an exclamation sign
(!)
...
Suppose we have an operand A
...
!A
True
False
False
TE
CH
A
True
If the value of argument is false, NOT operator will return
true, and vice versa
...
! (12 > 20)
In this case, the value of argument is false, but as we are
using the NOT operator, we will get the true as a result
...
Case 2:
1
...
Logical AND Operator
The logical AND operator is represented as the '&&' double
ampersand
operands
symbol
...
Else it returns false or 0
...
Otherwise, the logical AND (&&) operator returns
0 (false)
...
both
the
conditions are true, the logical AND operator
TE
CH
If
returns Boolean value 1 or true
...
Truth table of the Logical AND (&&) operator
A
B
A && B
1
1
1
1
0
0
0
1
0
0
0
0
-
Program to demonstrate the Logical AND Operator in C
#include
h>
HI
int main ()
{
// declare variable
int n = 20;
// use Logical AND (&&) operator to check the condition
printf (" %d \n", (n == 20 && n >= 8)); // condition is true,
therefore it returns 1
printf (" %d \n", (n >= 1 && n >= 20));
printf (" %d \n", (n == 10 && n >= 0));
printf (" %d \n", (n >= 20 && n <= 40));
C - LANGUAGE
66
HI - TECH COMPUTERS
return 0;
}
Output
1
1
0
Program
to
find
the
operator
#include
h>
int main ()
{
TE
CH
1
largest
number
using
the
Logical
// declare integer type variable
int x, y, z;
-
printf (" Enter the first number: ");
scanf ("%d", &x);
printf (" Enter the second number: ");
scanf ("%d", &y);
HI
printf (" Enter the third number: ");
scanf ("%d", &z);
// use logical AND operator to validate the condition
if ( x>= y && x >= z )
{
printf (" %d is the largest number of all
...
", y);
}
C - LANGUAGE
67
AND
HI - TECH COMPUTERS
else
{
printf( " %d is the largest number of all
...
#include
h>
-
int main ()
{
// declare variable
HI
int age;
printf (" Enter the age: ");
scanf (" %d", &age); // get age
//
use
logical
AND
operator
to
check
more
than
condition
if ( age>= 13 && age <= 19)
{
printf (" %d is a teenager age
...
", age);
}
return 0;
}
Output
17 is a teenager age
...
Program
to
validate
defined range or not
...
h>
{
int num;
-
int main ()
printf (" Enter a number between 1 to 50: ");
HI
scanf (" %d", &num); //get the number
// use logical AND operator to check condition
if ( (num> 0 ) && (num<= 50))
{
printf (" The entered number is in the range 0 and 50
...
");
}
else
C - LANGUAGE
69
HI - TECH COMPUTERS
{
printf (" Please enter the number is in the defined range
...
2nd Run
Enter a number between 1 to 50:
51
The entered number is in the range 50 and 100
...
HI
Program to validate the username and password entered by the
user
is
correct
or
not
using
the
predefined
username
and
password
...
h>
#include
");
}
else
{
printf( " \n The user's credentials are incorrect
...
2nd execution
Enter the username: system
Enter the password: admin@1234
The user's credentials are incorrect
...
When we perform the
bitwise
operations,
then
it
is
also
known
as
bit-level
programming
...
It is
mainly used in numerical computations to make the calculations
We
have
different
TE
CH
faster
...
The following is the list of the bitwise
operators:
Operator
Meaning of operator
Bitwise AND operator
|
Bitwise OR operator
^
Bitwise exclusive OR operator
~
One's complement operator (unary operator)
<<
Left shift operator
>>
Right shift operator
-
&
Let's look at the truth table of the bitwise operators
...
Two integer operands are written on both sides of the (&)
operator
...
C - LANGUAGE
72
is
1;
HI - TECH COMPUTERS
For example,
We have two variables a and b
...
e
...
If the bit of both the
variables is 1 then the output would be 1, otherwise 0
...
#include
e
...
The values of 'a' and 'b' are 6 and 14 respectively
...
When we apply the AND operator between these two
variables,
a AND b = 0110 && 1110 = 0110
Output
C - LANGUAGE
73
HI - TECH COMPUTERS
Bitwise OR operator
The bitwise OR operator is represented by a single vertical
sign (|)
...
If the bit value of any of the operand is 1,
then the output would be 1, otherwise 0
...
e
...
HI
Let's understand the bitwise OR operator through a program
...
h>
int main()
{
int a=23,b=10;
// variable declarations
printf("The output of the Bitwise OR operator a|b is %d",a|b);
return 0;
}
Output
C - LANGUAGE
74
HI - TECH COMPUTERS
Bitwise exclusive OR operator
Bitwise exclusive OR operator is denoted by (^) symbol
...
If the corresponding bit of any of the operand is 1
then the output would be 1, otherwise 0
...
-
value of any of the operand is 1, then the output would be 1
Let's understand the bitwise exclusive OR operator through a
HI
program
...
h>
int main()
{
int a=12,b=10;
// variable declarations
printf("The output of the Bitwise exclusive OR operator a^b is
%d",a^b);
return 0;
}
Output
C - LANGUAGE
75
HI - TECH COMPUTERS
Bitwise complement operator
The
bitwise
complement
operator
is
also
known
as
one's
complement operator
...
It
takes
complement
complement
only
one
operation
on
operation
on
operand
an
any
or
variable
operand
...
If we have a variable named 'a',
a = 8;
The
binary
representation
below:
a = 1000
of
the
above
variable
is
given
When we apply the bitwise complement operator to the operand,
then the output would be:
Result = 0111
As we can observe from the above result that if the bit is 1,
-
then it gets changed to 0 else 1
...
#include
The bitwise shift operators will shift the bits either on the
left-side
or
right-side
...
TE
CH
Right-shift operator
shifts
the
number
of
bits
to the
Syntax of the left-shift operator is given below:
Operand << n
Where,
is
an
integer
expression
on
which
we
apply
the
-
Operand
left-shift operation
...
In the case of Left-shift operator, 'n' bits will be shifted
on the left-side
...
For example,
Suppose we have a statement:
int a = 5;
The binary representation of 'a' is given below:
a = 0101
C - LANGUAGE
77
HI - TECH COMPUTERS
If we want to left-shift the above representation by 2, then
the statement would be:
a << 2;
0101<<2 = 00010100
Let's understand through a program
...
h>
{
TE
CH
int main()
int a=5; // variable initialization
printf("The value of a<<2 is : %d ", a<<2);
return 0;
}
Output
Right-shift operator
It is an operator that shifts the number of bits to the right
side
...
N is the number of bits to be shifted
...
The 'n' bits on the right-side will
be popped out, and 'n' bits on the left-side are filled with
0
...
#include
It is widely used for documenting code
...
Single Line Comments
Single Line Comments
TE
CH
Multi-Line Comments
Single line comments are represented by double slash \\
...
#include
For
HI
Even
example:
printf("Hello C");//printing information
Mult Line Comments
Multi-Line comments are represented by slash asterisk \*
...
It can occupy many lines of code, but it can't be nested
...
#include
The format string determines the format
of the input and output
...
The commonly used format specifiers in printf() function are:
Format
Description
%d or %i
It
is
used
TE
CH
specifier
to
the
signed
integer value
where signed integer means that the variable can
hold both positive and negative values
...
%o
It is used to print the octal unsigned integer
where octal integer value always starts with a 0
%x
-
value
...
In
this,
are
printed
in
small
letters such as a, b, c, etc
...
%f
It
is
used
for
printing
the
decimal
floating-point values
...
C - LANGUAGE
82
HI - TECH COMPUTERS
%e/%E
It is used for scientific notation
...
%g
It is used to print the decimal floating-point
values, and it uses the fixed precision, i
...
,
the value after the decimal in input would be
exactly the same as the value in the output
...
TE
CH
%p
%c
It is used to print the unsigned character
...
%ld
It
is
value
...
-
● %d
1
...
{
int b=6;
4
...
printf("Value of b is:%d", b);
6
...
7
...
return 0;
9
...
Output
C - LANGUAGE
83
HI - TECH COMPUTERS
● %u
1
...
{
3
...
int c= -10;
5
...
printf("\nValue of c is:%u",c);
8
...
}
TE
CH
7
...
e
...
The value of
b is positive, so %u specifier prints the exact value of b,
but
it
does
not
negative value
...
int main()
2
...
printf("Octal value of a is: %o", a);
5
...
6
...
}
In
the
above
code,
we
are
displaying
the octal value and
integer value of a
...
int main()
2
...
int y=0xA;
4
...
printf("\nHexadecimal value of y is: %X",y);
6
...
return 0;
8
...
We
display the hexadecimal value of y in two formats
...
e
...
int main()
2
...
e
...
3
...
4;
4
...
return 0;
6
...
Output
● %e
HI
1
...
{
3
...
printf("Exponential value of y is: %e", y);
5
...
}
Output
● %E
1
...
{
3
...
printf("Exponential value of y is: %E", y);
5
...
}
Output
● %g
1
...
{
float y=3
...
printf("Float value of y is: %g", y);
5
...
}
TE
CH
3
...
The %g specifier displays the output
same as the input with a same precision
...
int main()
2
...
int y=5;
4
...
return 0;
6
...
int main()
2
...
char a='c';
4
...
return 0;
6
...
int main()
2
...
printf("%s", "java");
4
...
}
Minimum Field Width Specifier
number
of
spaces
on
TE
CH
Suppose we want to display an output that occupies a minimum
the
screen
...
1
...
{
3
...
printf("%8d", x);
5
...
return 0;
-
7
...
HI
Output
Now we will see how to fill the empty spaces
...
int main()
2
...
int x=12;
4
...
return 0;
6
...
Output
C - LANGUAGE
87
HI - TECH COMPUTERS
Specifying Precision
We can specify the precision by using '
...
1
...
{
3
...
2;
4
...
2f", x);
5
...
}
HI
-
Output
C - LANGUAGE
88
HI - TECH COMPUTERS
Escape Sequence in C
An escape sequence in C language is a sequence of characters
that doesn't represent itself when used inside string literal
or character
...
For example: \n represents new line
...
h>
int main(){
int number=50;
printf("You\nare\nlearning\n\'c\'
language\n\"Do
you
know
language\"");
return 0;
}
Output:
C - LANGUAGE
89
C
HI - TECH COMPUTERS
You
are
learning
'c' language
"Do you know C language"
What is ASCII code?
The
full
form
information
used
for
of
ASCII
interchange
...
Each
character
or
a
special character is represented by some ASCII code, and each
ascii code occupies 7 bits in memory
...
The ascii value represents the character
-
variable in numbers, and each character variable is assigned
with some number range from 0 to 127
...
HI
In the above example, we assign 'A' to the character variable
whose ascii value is 65, so 65 will be stored in the character
variable rather than 'A'
...
Play Video
We will create a program which will display the ascii value of
the character variable
...
h>
int main()
C - LANGUAGE
90
HI - TECH COMPUTERS
{
char ch;
// variable declaration
printf("Enter a character");
scanf("%c",&ch);
// user input
printf("\n The ascii value of the ch variable is : %d", ch);
return 0;
}
In the above code, the first user will give the character
TE
CH
input, and the input will get stored in the 'ch' variable
...
e
...
Output
ASCII value in C
The above output shows that the user gave the input as 'A',
after
giving
input,
the
ascii
value
of
'A'
will
get
-
and
printed, i
...
, 65
...
#include
As we know that ascii value of all the characters
starts from 0 and ends at 255, so we iterate the for loop from
0 to 255
...
h>
int main()
{
int sum=0;
// variable initialization
char name[20];
int i=0;
TE
CH
of a string
...
After
taking user input, we execute the while loop which adds the
ascii value of all the characters of a string and stores it in
a 'sum' variable
...
e
...
type
that
contains
Basically,
the
two
bool
types of
type
value
represents two types of behavior, either true or false
...
In
C Boolean, '0' is stored as 0, and another integer is
stored as 1
...
e
...
h
...
Syntax
bool variable_name;
In the above syntax, bool is the data type of the variable,
and variable_name is the name of the variable
...
-
Play Video
#include
h>
HI
int main()
{
bool x=false; // variable initialization
...
h> header file so
that we can use the bool type variable in our program
...
Then, we add
the
conditional
statements,
i
...
,
if
...
The value of x is FALSE
Boolean Array
Now,
we
create
a
bool
TE
CH
Output
type
array
...
Let's understand this scenario through an example
...
h>
#include
e
...
Output
1,0,
C - LANGUAGE
94
HI - TECH COMPUTERS
typedef
There is another way of using Boolean value, i
...
, typedef
...
Let's see a simple example of typedef
...
h>
typedef enum{false,true} b;
TE
CH
int main()
{
b x=false; // variable initialization
if(x==true) // conditional statements
{
printf("The value of x is true");
}
else
{
printf("The value of x is false");
return 0;
}
-
}
In the above code, we use the Boolean values, i
...
, true and
HI
false, but we have not used the bool type
...
In order to
achieve this, the typedef keyword is used in the program
...
e
...
We
use the 'b' type in our program and create the 'x' variable of
type 'b'
...
There are three types of logical operators in the C language:
&&(AND
Operator):
It
is a logical operator that takes two
operands
...
If the value of both the operands is false, then it
returns false otherwise true
...
If the value of the operand is false, then it returns true,
and
if the value of the operand is true, then it returns
false
...
-
#include
h>
int main()
{
HI
bool x=false;
bool y=true;
printf("The value of x&&y is %d", x&&y);
printf("\nThe value of x||y is %d", x||y);
printf("\nThe value of !x is %d", !x);
}
Output
The value of x&&y is 0
The value of x||y is 1
The value of !x is 1
C - LANGUAGE
96
HI - TECH COMPUTERS
Static in C
Static is a keyword used in C programming language
...
e
...
An
ordinary
variable is limited to the scope in which it is defined, while
TE
CH
the scope of the static variable is throughout the program
...
It is declared at the
top
of
the
program,
and
program
...
Its lifetime is throughout the program
...
The memory of a static
HI
local variable is valid throughout the program, but the scope
of visibility of a variable is the same as the automatic local
variables
...
Static member variables
When the member variables are declared with a static keyword
in a class, then it is known as static member variables
...
Static method
C - LANGUAGE
97
HI - TECH COMPUTERS
The member function of a class declared with a static keyword
is
known as a static method
...
Let's understand through an example
...
h>
int main()
printf("%d",func());
printf("\n%d",func());
return 0;
}
int func()
{
TE
CH
{
int count=0; // variable initialization
count++; // incrementing counter variable
return count; }
-
In the above code, the func() function is called
...
As soon as the function completes
its
execution,
the
memory
of
the
count
variable
will
be
removed
...
HI
then
If we
declare the variable as static, then the variable will not be
removed from the memory even when the function completes its
execution
...
Syntax
The syntax of a static variable is given below:
static data_typevariable_name;
#include
int func()
-
{
static int count=0;
count++;
return count;
HI
}
In the above code, we have declared the count variable as
static
...
Therefore, we can say that the
value
of
the
static
variable
persists
within
the
function
call
...
In the above syntax, the expression1 is a Boolean condition
that can be either true or false value
...
The expression2 is said to be true only when it returns a
non-zero value
...
The expression3 is said to be false only when it returns zero
value
...
#include
After taking input, we have applied the condition by
using
a
checking
conditional
operator
...
If the age of the user is
age
of
In
this
condition,
we
are
greater than or equal to 18, then the statement1 will execute,
i
...
,
(printf("eligible
for
voting"))
otherwise,
statement2
will execute, i
...
, (printf("not eligible for voting"))
...
C - LANGUAGE
100
HI - TECH COMPUTERS
If we provide the age of user below 18, then the output would
be:
Conditional Operator in C
As
we can observe from the above two outputs that if the
condition is true, then the statement1 is executed; otherwise,
Till
now,
we
have
TE
CH
statement2 will be executed
...
Now, we will see how a conditional operator is
used to assign the value to a variable
...
#include
e
...
After the
declaration, we are assigning value to the 'b' variable by
using the conditional operator
...
Output
C - LANGUAGE
101
HI - TECH COMPUTERS
The above output shows that the value of 'b' variable is 3
because the value of 'a' variable is equal to 5
...
Let's
look at their differences
...
A conditional operator can also be used for assigning a value
to the variable, whereas the 'if-else' statement cannot be
used for the assignment purpose
...
The
nested
ternary
operator is more complex and cannot be
-
easily debugged, while the nested 'if-else' statement is easy
HI
to read and maintain
...
As we know that the 1s complement of a binary number is
created
by
transforming
bit
1
to
0
and
0
to
1;
the
2s
complement of a binary number is generated by adding one to
the 1s complement of a binary number
...
In the above figure, the binary number is equal to 00010100,
and its one's complement is calculated by transforming the bit
1 to 0 and 0 to 1 vice versa
...
calculate
the
After
two's
calculating
complement
by
one's
adding
complement,
1
to
the
we
one's
complement, and its result is 11101100
...
#include
The operations specified in
if block are executed if and only if the given condition is
true
...
The if statement is used to check some given condition and
perform some operations depending upon the correctness of that
condition
...
The syntax of the if statement is given below
...
if(expression)
2
...
//code to be executed
HI
4
...
1
...
h>
2
...
int number=0;
4
...
scanf("%d",&number);
6
...
printf("%d is even number",number);
8
...
return 0;
10
...
1
...
h>
3
...
int a, b, c;
5
...
int main()
printf("Enter three numbers?");
6
...
if(a>b && a>c)
8
...
printf("%d is largest",a);
10
...
if(b>a
12
...
&& b > c)
14
...
if(c>a && c>b)
16
...
18
...
if(a == b && a == c)
20
...
printf("All are equal");
22
...
}
}
Output
Enter three numbers?
12 23 34
34 is largest
C - LANGUAGE
107
HI - TECH COMPUTERS
If-else Statement
The if-else statement is used to perform two operations for a
single condition
...
e
...
Here, we must notice that the if and else block
cannot be executed simultaneously
...
The syntax of the if-else statement
is given below
...
if(expression){
2
...
}else{
4
...
}
Let's see the simple example to check whether a number is even
-
or odd using if-else statement in C language
...
#include
int main(){
3
...
printf("enter a number:");
5
...
if(number%2==0){
7
...
}
9
...
printf("%d is odd number",number);
11
...
return 0;
13
...
1
...
h>
2
...
{
int age;
5
...
scanf("%d",&age);
7
...
{
9
...
");
10
...
else
12
...
printf("Sorry
...
15
...
Enter your age?18
HI
You are eligible to vote
...
you can't vote
If else-if ladder Statement
The if-else-if ladder statement is an extension to the if-else
statement
...
In if-else-if
ladder statement, if a condition is true then the statements
defined in the if block will be executed, otherwise if some
other condition is true then the statements defined in the
else-if block will be executed, at the last if none of the
C - LANGUAGE
109
HI - TECH COMPUTERS
condition
block
is
will
true
be
then the statements defined in the else
executed
...
It is similar to the switch case statement where the
default is executed instead of else block if none of the cases
is matched
...
if(condition1){
2
...
}else if(condition2){
5
...
else if(condition3){
TE
CH
4
...
//code to be executed if condition3 is true
8
...
10
...
//code to be executed if all the conditions are false
12
...
1
...
h>
2
...
int number=0;
4
...
scanf("%d",&number);
6
...
printf("number is equals to 10");
8
...
else if(number==50){
10
...
}
12
...
printf("number is equal to 100");
14
...
else{
16
...
}
18
...
}
Output
enter a number:4
enter a number:50
number is equal to 50
TE
CH
number is not equal to 10, 50 or 100
Program to calculate the grade of the student according to the
specified marks
...
#include
int main()
3
...
printf("Enter your marks?");
6
...
if(marks > 85 && marks <= 100)
8
...
9
...
printf("Congrats ! you scored grade A
...
else if (marks > 60 && marks <= 85)
12
...
printf("You scored grade B +
...
}
15
...
{
17
...
");
18
...
else if (marks > 30 && marks <= 40)
20
...
C - LANGUAGE
printf("You scored grade C
...
}
23
...
{
25
...
");
26
...
}
}
Output
Sorry you are fail
...
Enter your marks?90
TE
CH
Enter your marks?10
HI
-
Congrats ! you scored grade A
...
Here, We can define various statements in the
multiple cases for the different values of a single variable
...
case value1:
TE
CH
1
...
//code to be executed;
4
...
case value2:
6
...
break;
//optional
8
...
default:
10
...
code to be executed if all cases are not matched;
Rules for switch statement in C language
1) The switch expression must be of an integer or character
type
...
3)
The
case
value
can
be
used
only
inside
the
switch
statement
...
It is
optional
...
It is known as fall through the state of C switch statement
...
We are assuming
that there are following variables
...
int x,y,z;
2
...
float f;
C - LANGUAGE
113
HI - TECH COMPUTERS
Invalid
Valid
Invalid
Switch
Case
Case
switch(x)
switch(f)
case 3;
case 2
...
5)
case 'a';
case x;
switch(a+b-2)
case 1+2;
case x+2;
switch(func(x,y))
case
case 1,2,3;
TE
CH
Valid Switch
'x'>'y';
Functioning of switch case statement
First,
the
integer
expression
specified
in
the
switch
statement is evaluated
...
If a
match is found, then all the statements specified in that case
are executed along with the all the cases present after that
case including the default statement
...
statement,
If
the
matched
-
similar
then
all
the
cases
case
present
contains
after
that
a
break
will
be
skipped, and the control comes out of the switch
...
HI
Let's see a simple example of c language switch statement
...
#include
int main(){
3
...
printf("enter a number:");
5
...
switch(number){
7
...
printf("number is equals to 10");
9
...
case 50:
C - LANGUAGE
114
HI - TECH COMPUTERS
printf("number is equal to 50");
12
...
case 100:
14
...
break;
16
...
printf("number is not equal to 10, 50 or 100");
18
...
return 0;
20
...
number is not equal to 10, 50 or 100
enter a number:50
number is equal to 50
-
Switch case example 2
1
...
h>
2
...
{
int x = 10, y = 5;
HI
4
...
switch(x>y && x+y>0)
6
...
case 1:
8
...
break;
10
...
printf("bye");
12
...
default:
14
...
C - LANGUAGE
}
115
HI - TECH COMPUTERS
16
...
}
Output
hi
C Switch statement is fall-through
In C language, the switch statement is fall through; it means
if you don't use a break statement in the switch case, all the
Let's
try
to
understand
TE
CH
cases after the matching case will be executed
...
1
...
h>
2
...
int number=0;
4
...
printf("enter a number:");
6
...
switch(number){
-
8
...
printf("number is equal to 10\n");
case 50:
11
...
case 100:
HI
10
...
printf("number is equal to 100\n");
14
...
printf("number is not equal to 10, 50 or 100");
16
...
return 0;
18
...
Such type of statements is called nested switch
case statements
...
1
...
h>
2
...
4
...
int j = 20;
6
...
8
...
case 10:
10
...
case 20:
12
...
case 20:
14
...
16
...
18
...
printf("Exact value of j is : %d\n", j );
20
...
22
...
There are
three types of loops used in the C language
...
Why use loops in C language?
looping
simplifies
the
complex
problems
into
the
TE
CH
The
easy
ones
...
For
example, if we need to print the first 10 natural numbers
then, instead of using the printf statement 10 times, we can
print inside a loop which runs up to 10 iterations
...
-
2) Using loops, we do not need to write the same code again
3) Using loops, we can traverse over the elements of data
structures (array or linked lists)
...
do while
2
...
for
do-while loop in C
The do-while loop continues until a given condition satisfies
...
It is used when it is
necessary
to
execute
the
loop
at
least
once
(mostly
driven programs)
...
do{
2
...
}while(condition);
while loop in C
The while loop in c is to be used in the scenario where we
TE
CH
don't know the number of iterations in advance
...
It is also called a
pre-tested loop
...
while(condition){
2
...
}
-
for loop in C
The for loop is used in the case where we need to execute some
part of the code until the given condition is satisfied
...
It is better to
HI
use for loop if the number of iteration is known in advance
...
for(initialization;condition;incr/decr){
2
...
}
C - LANGUAGE
120
HI - TECH COMPUTERS
do while loop in C
The do while loop is a post tested loop
...
The do-while loop is mainly used in the case where
we need to execute the loop at least once
...
do while loop syntax
1
...
//code to be executed
3
...
#include
#include
void main ()
4
...
int choice,dummy;
7
...
printf("\n1
...
Print Java\n3
...
scanf("%d",&choice);
switch(choice)
HI
10
...
11
...
case 1 :
13
...
break;
15
...
printf("Java");
17
...
case 3:
19
...
break;
21
...
printf("please enter valid choice");
23
...
printf("do you want to enter more?");
25
...
scanf("%c",&c);
27
...
}
Output
TE
CH
1
...
Print Java
3
...
Print Hello
2
...
Exit
do you want to enter more?
HI
n
do while example
There is given the simple program of c language do while loop
where we are printing the table of 1
...
#include
int main(){
3
...
do{
5
...
i++;
7
...
return 0;
9
...
#include
int main(){
-
3
...
printf("Enter a number: ");
5
...
do{
HI
7
...
i++;
9
...
return 0;
11
...
HI
1
...
//statement
3
...
In general, a
while loop allows a part of the code to be executed multiple
times
depending
upon
a given boolean condition
...
The while loop is mostly
used in the case where the number of iterations is not known
in advance
...
while(condition){
TE
CH
The syntax of while loop in c language is given below:
2
...
}
Example of the while loop in C language
Let's see the simple program of while loop that prints table
of 1
...
#include
int main(){
-
3
...
while(i<=10){
5
...
i++;
HI
7
...
return 0;
9
...
#include
int main(){
3
...
scanf("%d",&number);
6
...
printf("Enter a number: ");
7
...
i++;
9
...
return 0;
11
...
defined
inside
the
while
loop
will
repeatedly execute until the given condition fails
...
The condition
will be false if it returns any non-zero number
...
● Running a while loop without a body is possible
...
● If the loop body contains only one statement, then the
Example 1
-
braces are optional
...
#include
void main ()
HI
3
...
int j = 1;
5
...
{
7
...
}
9
...
}
Output
3 5 7 9 11
C - LANGUAGE
127
HI - TECH COMPUTERS
Example 2
1
...
h>
2
...
{
4
...
{
6
...
}
Output
TE
CH
7
...
#include
void main ()
3
...
while(x+y-1)
6
...
8
...
printf("%d %d",x--,y--);
}
9
...
1
...
//statement
3
...
It is frequently used
to
traverse
the
data structures like the array and linked
list
...
for(Expression 1; Expression 2; Expression 3){
3
...
//code to be executed
Let's see the simple program of for loop that prints table of
1
...
#include
int main(){
3
...
for(i=1;i<=10;i++){
6
...
return 0;
-
5
...
}
HI
Output
1
2
3
4
5
6
7
8
9
10
C - LANGUAGE
129
HI - TECH COMPUTERS
C Program: Print table for the given number using C for loop
1
...
h>
2
...
int i=1,number=0;
4
...
scanf("%d",&number);
6
...
}
9
...
}
Output
Enter a number: 2
2
4
6
8
TE
CH
7
...
● We can initialize more than one variable in Expression 1
...
● In C, we can not declare the variables in Expression 1
...
#include
int main()
3
...
4
...
for(a=0,b=12,c=23;a<2;a++)
6
...
printf("%d ",a+b+c);
}
9
...
HI
35 36
Example 2
1
...
h>
2
...
{
4
...
for(;i<5;i++)
6
...
8
...
}
C - LANGUAGE
131
HI - TECH COMPUTERS
Output
1 2 3 4
Properties of Expression 2
● Expression 2 is a conditional expression
...
If it is not, the
loop is terminated
...
However,
TE
CH
the loop will iterate until the last condition becomes
false
...
● Expression 2 is optional
...
That is, we can initialize the variable as
well as update the loop variable in expression 2 itself
...
However, in C, any non-zero value is true, and zero is
false by default
...
#include
int main()
3
...
for(i=0;i<=4;i++)
6
...
7
...
printf("%d ",i);
}
9
...
#include
int main()
C - LANGUAGE
132
HI - TECH COMPUTERS
3
...
int i,j,k;
5
...
{
7
...
j+=2;
9
...
}
TE
CH
11
...
#include
int main()
3
...
for(i=0;;i++)
6
...
7
...
printf("%d",i);
}
9
...
● We can update more than one variable at the same time
...
C - LANGUAGE
133
HI - TECH COMPUTERS
Example 1
1
...
h>
2
...
{
4
...
for(i = 0;i<5;i++,j=j+2)
6
...
printf("%d %d\n",i,j);
}
TE
CH
8
...
}
Output
0 2
1 4
2 6
3 8
4 10
Loop body
braces
However,
if
{}
are
used
to
define
the
scope
of
the loop
...
A loop without a body is possible
...
e
...
Consider the following example
...
#include
void main ()
3
...
int i;
5
...
{
7
...
printf("%d ",i);
9
...
}
}
C - LANGUAGE
134
HI - TECH COMPUTERS
Output
20 20 20 20 20 20 20 20 20 20
Infinitive for loop in C
To make a for loop infinite, we need not give any expression
in
the
syntax
...
This will
1
...
h>
2
...
{
4
...
{
6
...
TE
CH
work as an infinite for loop
...
}
If you run this program, you will see above statement infinite
HI
-
times
...
Nesting of loops is the
feature
in
C
that allows the looping of statements inside
another loop
...
Any number of loops can be defined inside another loop, i
...
,
there is no restriction for defining any number of loops
...
You can define any
type of loop inside another loop; for example, you can define
Syntax of Nested loop
1
...
{
3
...
Inner_loop
{
5
...
TE
CH
'while' loop inside a 'for' loop
...
}
7
...
8
...
Nested for loop
HI
The nested for loop means any type of loop which is defined
inside the 'for' loop
...
for (initialization; condition; update)
2
...
for(initialization; condition; update)
4
...
// inner loop statements
...
}
7
...
8
...
#include
int main()
3
...
int n;// variable declaration
5
...
// Displaying the n tables
...
for(int i=1;i<=n;i++)
8
...
// outer loop
for(int j=1;j<=10;j++)
10
...
printf("%d\t",(i*j)); // printing the value
...
}
13
...
// inner loop
}
Explanation of the above code
● First,
the
'i'
variable is initialized to 1 and then
-
program control passes to the i<=n
...
● If the condition is true, then the program control passes
HI
to the inner loop
...
● After the execution of the inner loop, the control moves
back to the update of the outer loop, i
...
, i++
...
e
...
● If the condition is true, then the inner loop will be
executed again
...
C - LANGUAGE
137
HI - TECH COMPUTERS
Nested while loop
TE
CH
Output:
The nested while loop means any type of loop which is defined
inside the 'while' loop
...
while(condition)
2
...
while(condition)
4
...
// inner loop statements
...
}
7
...
-
8
...
#include
int main()
HI
3
...
int rows;
5
...
int k=1; // variable initialization
7
...
8
...
printf("\nEnter the number of columns :"); // input
the number of columns
...
scanf("%d",&columns);
11
...
int i=1;
13
...
{
15
...
while(j<=columns)
17
...
printf("%d\t",k);
// printing the value of
k
...
j++;
// increment counter
TE
CH
19
...
}
22
...
printf("\n");
24
...
}
}
Explanation of the above code
...
e
...
● The program initializes the 'i' variable by 1
...
● After the execution of the inner loop, the control moves
HI
to the update of the outer loop, i
...
, i++
...
● If the condition is true, the control then again moves to
the inner loop
...
C - LANGUAGE
139
HI - TECH COMPUTERS
Nested do
...
while loop means any type of loop which is
defined inside the 'do
...
1
...
{
3
...
do
{
6
...
-
5
...
// outer loop statements
...
}while(condition);
HI
Example of nested do
...
1
...
h>
2
...
{
4
...
********
6
...
********
8
...
int i=1;
10
...
{
C - LANGUAGE
// outer loop
140
HI - TECH COMPUTERS
12
...
do
14
...
printf("*");
16
...
printf("\n");
19
...
21
...
Explanation of the above code
...
e
...
HI
● As we know that the do
...
● After the execution of the inner loop, the control moves
to the update of the i++
...
If the condition in the outer loop is true,
then the inner loop is executed
...
C - LANGUAGE
141
HI - TECH COMPUTERS
Infinite Loop in C
An
infinite
loop
is
a
looping
construct
that
does
not
terminate the loop and executes the loop forever
...
It
either
produces a continuous output or no output
...
In the following
situations, this type of loop can be used:
● All the operating systems run in an infinite loop as it
does not exist after performing some task
...
● All the servers run in an infinite loop as the server
responds to all the client requests
...
-
● All the games also run in an infinite loop
...
We
can
create
The
infinite
following
HI
structures
...
The
following
is
the
definition for the infinite for loop:
1
...
{
3
...
4
...
Let's understand through an example
...
#include
int main()
3
...
for(;;)
5
...
printf("Hello java");
}
8
...
9
...
C - LANGUAGE
143
HI - TECH COMPUTERS
while loop
Now, we will see how to create an infinite loop using a while
loop
...
while(1)
2
...
// body of the loop
...
}
As
we
know
that
any
TE
CH
In the above while loop, we put '1' inside the loop condition
...
Let's look at a simple example
...
#include
int main()
3
...
int i=0;
5
...
{
i++;
8
...
}
10
...
}
HI
9
...
The value
of 'i' will be updated an infinite number of times
...
while loop
The do
...
The
following
is
the
syntax
to
create
the
infinite
do
...
1
...
{
3
...
4
...
while loop represents the infinite condition as
we provide the '1' value inside the loop condition
...
C - LANGUAGE
145
true
HI - TECH COMPUTERS
C break statement
The break is a keyword in C which is used to bring the program
control out of the loop
...
The break statement breaks the loop
one by one, i
...
, in the case of nested loops, it breaks the
inner loop first and then proceeds to outer loops
...
With loop
Syntax:
TE
CH
1
...
//loop or switch case
2
...
#include
#include
void main ()
4
...
for(i = 0; i<10; i++)
7
...
printf("%d ",i);
9
...
10
...
}
12
...
14
...
1
...
h>
2
...
int i=1,j=1;//initializing a local variable
5
...
for(i=1;i<=3;i++){
6
...
if(i==2 && j==2){
8
...
}
10
...
return 0;
12
...
But 3 1, 3 2 and 3 3 are printed because the break
statement is used to break the inner loop only
...
C - LANGUAGE
147
HI - TECH COMPUTERS
1
...
h>
2
...
{
int i = 0;
5
...
{
7
...
i++;
9
...
",i);
break;
11
...
printf("came out of while loop");
13
...
1
2
3
4
5
6
7
8
9
came out of while loop
break statement with do-while loop
Consider the following example to use the break statement with
-
a do-while loop
...
#include
void main ()
HI
3
...
int n=2,i,choice;
5
...
{
7
...
while(i<=10)
9
...
printf("%d X %d = %d\n",n,i,n*i);
11
...
13
...
",n+1);
C - LANGUAGE
148
HI - TECH COMPUTERS
14
...
if(choice == 0)
16
...
break;
18
...
n++;
20
...
}while(1);
}
TE
CH
Output
2 X 1 = 2
2 X 2 = 4
2 X 3 = 6
2 X 4 = 8
2 X 5 = 10
2 X 6 = 12
2 X 7 = 14
2 X 8 = 16
2 X 9 = 18
do
you
want
-
2 X 10 = 20
to
continue with the table of 3 , enter any
non-zero value to continue
...
0
C - LANGUAGE
149
HI - TECH COMPUTERS
C continue statement
The continue statement in C language is used to bring the
program control to the beginning of the loop
...
It is mainly used for a
condition
so
that
we
can
skip
some
code for a particular
condition
...
//loop statements
2
...
//some lines of the code which is to be skipped
Continue statement example 1
1
...
h>
2
...
{
4
...
while(i!=10)
6
...
continue;
9
...
10
...
}
Output
infinite loop
Continue statement example 2
1
...
h>
2
...
int i=1;//initializing a local variable
4
...
for(i=1;i<=10;i++){
6
...
continue;
8
...
printf("%d \n",i);
10
...
return 0;
12
...
C continue statement with inner loop
In such case, C continue statement continues only inner loop,
HI
but not outer loop
...
#include
int main(){
3
...
for(i=1;i<=3;i++){
5
...
if(i==2 && j==2){
7
...
}
9
...
}
11
...
return 0;
13
...
C - LANGUAGE
152
HI - TECH COMPUTERS
C goto statement
The goto statement is known as jump statement in C
...
The goto statment can be used to repeat
some part of the code for a particular condition
...
However, using goto is avoided
these
days
since
it
makes
program
less
readable
TE
CH
complecated
...
label:
and
2
...
goto label;
goto example
Let's
see
a
simple
example
language
...
#include
int main()
-
3
...
int num,i=1;
5
...
7
...
printf("%d x %d = %d\n",num,i,num*i);
9
...
if(i<=10)
11
...
}
Output:
Enter the number whose table you want to print?10
10 x 1 = 10
10 x 2 = 20
10 x 3 = 30
C - LANGUAGE
153
to
HI - TECH COMPUTERS
10 x 4 = 40
10 x 5 = 50
10 x 6 = 60
10 x 7 = 70
10 x 8 = 80
10 x 9 = 90
When should we use goto?
TE
CH
10 x 10 = 100
The only condition in which using goto is preferable is when
we need to break the multiple loops using a single statement
at the same time
...
1
...
h>
2
...
{
4
...
for(i=0;i<10;i++)
6
...
{
9
...
for(k=0;k<3;k++)
10
...
12
...
{
14
...
}
16
...
}
18
...
out:
20
...
}
0 0 0
C - LANGUAGE
154
HI - TECH COMPUTERS
0 0 1
0 0 2
0 1 0
0 1 1
0 1 2
0 2 0
0 2 1
0 3 0
HI
-
came out of the loop
TE
CH
0 2 2
C - LANGUAGE
155
HI - TECH COMPUTERS
Type Casting in C
Typecasting allows us to convert one data type into other
...
Syntax:
1
...
int f= 9/4;
TE
CH
higher for avoiding data loss
...
printf("f : %d\n", f );//Output: 2
With Type Casting:
1
...
printf("f : %f\n", f );//Output: 2
...
-
1
...
h>
2
...
float f= (float)9/4;
4
...
return 0;
6
...
250000
C - LANGUAGE
156
HI - TECH COMPUTERS
C Functions
In c, we can divide a large program into the basic building
blocks known as function
...
A
function
can
be
called multiple times to provide reusability and modularity to
the C program
...
The function is also known as
procedureor subroutinein other programming languages
...
● By
using
functions,
we
can
avoid
rewriting
same
logic/code again and again in a program
...
● We can track a large C program easily when it is divided
into multiple functions
...
program
...
● Function declaration A function must be declared globally
HI
in a c program to tell the compiler about the function
name, function parameters, and return type
...
The parameter list must not differ in function
calling and function declaration
...
●
Function
definition
It
contains
the
actual
statements
which are to be executed
...
Here, we must notice that only one value can be returned
from the function
...
return_type function_name(data_type parameter
...
//code to be executed
3
...
Library Functions: are the functions which are declared
in the C header files such as scanf(), printf(), gets(),
puts(), ceil(), floor() etc
...
User-defined
functions:
are
the
functions
which
are
created by the C programmer, so that he/she can use it
many times
...
C - LANGUAGE
158
HI - TECH COMPUTERS
Return Value
A C function may or may not return a value from the function
...
Let's see a simple example of C function that doesn't return
any value from the function
...
printf("hello c");
3
...
void hello(){
If you want to return any value from the function, you need to
use any data type such as int, long, char, etc
...
Let's see a simple example of C function that returns int
value from the function
...
int get(){
2
...
}
In the above example, we have to return 10 as a value, so the
return type is int
...
g
...
2, 3
...
5, etc), you need to use float as the
HI
return type of the method
...
float get(){
2
...
2;
3
...
Different aspects of function calling
A function may or may not accept any argument
...
Based on these facts, There are four
C - LANGUAGE
159
HI - TECH COMPUTERS
different aspects of function calls
...
void printName();
3
...
{
TE
CH
1
...
h>
5
...
printName();
7
...
void printName()
9
...
}
Output
Hello Java
-
11
...
#include
void sum();
3
...
{
5
...
sum();
7
...
void sum()
9
...
int a,b;
11
...
scanf("%d %d",&a,&b);
13
...
}
Output
Going to calculate the sum of two numbers:
Enter two numbers 10
The sum is 34
TE
CH
24
Example for Function without argument and with return value
Example 1
1
...
h>
2
...
void main()
4
...
int result;
6
...
result = sum();
8
...
}
int sum()
HI
10
...
{
12
...
printf("\nEnter two numbers");
14
...
return a+b;
16
...
#include
int sum();
3
...
{
printf("Going
square\n");
to
calculate
the
area
6
...
printf("The area of the square: %f\n",area);
8
...
int square()
10
...
11
...
printf("Enter the length of the side in meters: ");
13
...
return side * side;
}
-
15
...
000000
Example for Function with argument and without return value
Example 1
1
...
h>
2
...
void main()
4
...
int a,b,result;
6
...
printf("\nEnter two numbers:");
C - LANGUAGE
162
two
HI - TECH COMPUTERS
8
...
sum(a,b);
10
...
void sum(int a, int b)
12
...
14
...
1
...
h>
2
...
void main()
4
...
6
...
scanf("%d %d %d %d %d",&a,&b,&c,&d,&e);
HI
7
...
average(a,b,c,d,e);
10
...
void average(int a, int b, int c, int d, int e)
12
...
float avg;
14
...
printf("The
average
of
given
five
numbers
%f",avg);
16
...
000000
Example for Function with argument and with return value
Example 1
1
...
h>
2
...
void main()
4
...
int a,b,result;
6
...
scanf("%d %d",&a,&b);
9
...
10
...
printf("\nThe sum is : %d",result);
12
...
{
14
...
return a+b;
}
Output
Going to calculate the sum of two numbers:
Enter two numbers:10
20
The sum is : 30
C - LANGUAGE
164
two
HI - TECH COMPUTERS
Example 2: Program to check whether a number is even or odd
1
...
h>
2
...
void main()
4
...
int n,flag=0;
6
...
scanf("%d",&n);
9
...
if(flag == 0)
11
...
TE
CH
7
...
}
14
...
{
16
...
18
...
int even_odd(int n)
20
...
22
...
return 1;
24
...
else
26
...
return 0;
28
...
}
}
Output
Going to check whether a number is even or odd
Enter the number: 100
C - LANGUAGE
165
HI - TECH COMPUTERS
The number is even
C Library Functions
Library
functions
are
the
inbuilt
function
in
C
that
are
grouped and placed at a common place called the library
...
For
example, printf is a library function used to print on the
console
...
All C standard library functions are defined inside
the different header files saved with the extension
...
We
need to include these header files in our program to make use
of the library functions defined in such header files
...
h in our program which is a header file
that
contains
all
the
input/output
...
Header
N
file
1
stdio
...
HI
It
contains
all
the
library
functions
regarding standard input/output
...
h
This is a console input/output header file
...
h
It
contains
all
string
related
library
functions like gets(), puts(),etc
...
h
This
header
library
file
functions
contains all the general
like
malloc(),
calloc(),
exit(), etc
...
h
This
header
operations
file
contains
related
functions
all
the
like
math
sqrt(),
pow(), etc
...
h
This
header
file
contains
all
the
time-related functions
...
h
This
header
file
contains
all
character
8
stdarg
...
Variable argument functions are defined in
this header file
...
h
All the signal handling functions are defined
in this header file
...
h
This file contains all the jump functions
...
h
This file contains locale functions
...
h
This file contains error handling functions
...
h
-
10
HI
This file contains diagnostics functions
...
e
...
Let's understand call by value and call by reference in c
language one by one
...
In other
words, we can say that the value of the variable is used
in the function call in the call by value method
...
● In
call
actual
by
and
value,
formal
different
memory
is
parameters
since
the
allocated
for
value
the
of
actual parameter is copied into the formal parameter
...
C - LANGUAGE
168
HI - TECH COMPUTERS
Let's try to understand the concept of call by value in c
language by the example given below:
1
...
h>
2
...
printf("Before adding value inside function num=%d
\n",num);
4
...
}
7
...
8
...
printf("Before function call x=%d \n", x);
10
...
printf("After function call x=%d \n", x);
12
...
}
Output
-
Before function call x=100
Before adding value inside function num=100
After adding value inside function num=200
HI
After function call x=100
Call
by
Value
Example:
Swapping
the
values
of
the
two
variables
1
...
h>
2
...
int main()
4
...
int a = 10;
6
...
printf("Before swapping the values in main a = %d, b
= %d\n",a,b); // printing the value of a and b in main
8
...
printf("After swapping values in main a = %d, b =
%d\n",a,b);
change
by
//
The
value
changing
the
of
actual
formal
parameters
parameters
do
in
call
not
by
value, a = 10, b = 20
10
...
void swap (int a, int b)
12
...
temp = a;
15
...
b=temp;
17
...
= %d\n",a,b); // Formal parameters, a = 20, b = 10
18
...
HI
● The value of the actual parameters can be modified by
changing the formal parameters since the address of the
actual parameters is passed
...
All the
operations in the function are performed on the value
stored at the address of the actual parameters, and the
modified value gets stored at the same address
...
1
...
h>
2
...
printf("Before adding value inside function num=%d
\n",*num);
4
...
printf("After adding value inside function num=%d
\n", *num);
TE
CH
6
...
int main() {
8
...
printf("Before function call x=%d \n", x);
10
...
printf("After function call x=%d \n", x);
12
...
}
Output
Before function call x=100
-
Before adding value inside function num=100
After adding value inside function num=200
After function call x=200
by
reference
Example: Swapping the values of the two
HI
Call
variables
1
...
h>
2
...
int main()
4
...
int a = 10;
6
...
printf("Before swapping the values in main a = %d, b
= %d\n",a,b); // printing the value of a and b in main
8
...
printf("After swapping values in main a = %d, b =
%d\n",a,b); // The values of actual parameters do change
in call by reference, a = 10, b = 20
10
...
void swap (int *a, int *b)
12
...
temp = *a;
15
...
*b=temp;
17
...
= %d\n",*a,*b); // Formal parameters, a = 20, b = 10
18
...
Any function which calls itself is called recursive function,
and such function calls are called recursive calls
...
However, it is
important
to
impose
a
termination
condition
of
recursion
...
TE
CH
Recursion code is shorter than iterative code however it is
Recursion cannot be applied to all the problem, but it is more
useful for the tasks that can be defined in terms of similar
subtasks
...
Generally,
iterative
solutions
are
more
efficient
than
recursion since function call is always overhead
...
solved
However,
recursively,
some
problems
can
are
also
best
be
solved
suited
to
be
-
solved by the recursion, for example, factorial finding, etc
...
1
...
h>
HI
2
...
int main()
4
...
int n,f;
6
...
scanf("%d",&n);
8
...
printf("factorial = %d",f);
10
...
int fact(int n)
12
...
if (n==0)
14
...
return 0;
16
...
else if ( n == 1)
18
...
}
21
...
{
23
...
25
...
}
}
Output
Enter the number whose factorial you want to calculate?5
HI
-
factorial = 120
C - LANGUAGE
174
HI - TECH COMPUTERS
Storage Classes in C
Storage
classes
in
C
are
used
to
determine
the
lifetime,
visibility, memory location, and initial value of a variable
...
● The visibility of the automatic variables is limited to
the block in which they are defined
...
The automatic variables
are initialized to garbage by default
...
● The
keyword
used
for
defining
automatic
variables
is
auto
...
#include
int main()
3
...
int a; //auto
5
...
float c;
7
...
%f",a,b,c);
//
printing
initial
default
8
...
}
Output:
-
value of automatic variables a, b, and c
...
● Static local variables are visible only to the function
or the block in which they are defined
...
● Default initial value of the static integral variable is
0 otherwise null
...
● The keyword used to define static variable is static
...
#include
static char c;
4
...
static char s[100];
6
...
{
TE
CH
3
...
printf("%d %d %f %s",c,i,f); // the initial default value
of c, i, and f will be printed
...
}
Output:
0 0 0
...
HI
● We can not dereference the register variables, i
...
, we
can not use &operator for the register variable
...
● The initial default value of the register local variables
is 0
...
However, it is
compiler?s choice whether or not; the variables can be
stored in the register
...
e
...
● Static
variables
can
not
be
stored
into
the
register
since we can not use more than one storage specifier for
the same variable
...
int main()
3
...
#include
register int a; // variable a is allocated memory in the
CPU register
...
5
...
}
Output:
0
External
-
● The external storage class is used to tell the compiler
that the variable defined as extern is declared with an
external linkage elsewhere in the program
...
It is only declaration and intended to specify
that the variable is declared elsewhere in the program
...
● We
can
only
initialize
the
extern
variable
globally,
i
...
, we can not initialize the external variable within
any block or method
...
● If a variable is declared as external then the compiler
searches for that variable to be initialized somewhere in
C - LANGUAGE
178
HI - TECH COMPUTERS
the program which may be extern or static
...
Example 1
1
...
h>
2
...
{
4
...
printf("%d",a);
6
...
int a = 20;
Output
HI
-
20
TE
CH
a defined and initialized somewhere in the pogram or not
...
Arrays are the
derived data type in C programming language which can store
the primitive type of data such as int, char, double, float,
etc
...
The
array is the simplest data structure where each data element
TE
CH
can be randomly accessed by using its index number
...
For example, if we want to store the marks of a student in 6
subjects, then we don't need to define different variables for
the marks in the different subject
...
By using the array, we can access the elements easily
...
-
Properties of Array
The array contains the following properties
...
e
...
HI
● Elements of the array are stored at contiguous memory
locations
where
the
first
element
is
stored
at
the
smallest memory location
...
Advantage of C Array
1) Code Optimization: Less code to the access the data
...
C - LANGUAGE
180
HI - TECH COMPUTERS
3) Ease of sorting: To sort the elements of the array, we need
a few lines of code only
...
Disadvantage of C Array
1)
Fixed
Size:
Whatever
size,
we
define
at
the
time
of
declaration of the array, we can't exceed the limit
...
Declaration of C Array
TE
CH
doesn't grow the size dynamically like LinkedList which we
We can declare an array in the c language in the following
way
...
data_type array_name[array_size];
Now, let us see the example to declare the array
...
int marks[5];
Here, int is the data_type, marks are the array_name, and 5 is
the array_size
...
We can initialize each element of the array
by using the index
...
1
...
marks[1]=60;
3
...
marks[3]=85;
5
...
#include
int main(){
3
...
int marks[5];//declaration of array
5
...
marks[1]=60;
8
...
marks[4]=75;
TE
CH
7
...
//traversal of array
11
...
printf("%d \n",marks[i]);
13
...
return 0;
15
...
Let's see the code
...
int marks[5]={20,30,40,50,60};
In such case, there is no requirement to define the size
...
1
...
1
...
h>
2
...
int i=0;
4
...
for(i=0;i<5;i++){
TE
CH
5
...
printf("%d \n",marks[i]);
8
...
return 0;
10
...
1
...
h>
2
...
{
4
...
int a[10] = { 10, 9, 7, 101, 23, 44, 12, 78, 34, 23};
6
...
{
8
...
{
10
...
{
C - LANGUAGE
183
HI - TECH COMPUTERS
12
...
a[i] = a[j];
14
...
}
16
...
printf("Printing Sorted Element List
...
for(i = 0; i<10; i++)
20
...
printf("%d\n",a[i]);
22
...
TE
CH
17
...
The 2D array is organized as matrices which can be
represented as the collection of rows and columns
...
It provides ease of holding the bulk
of data at once which can be passed to any number of functions
wherever required
...
1
...
1
...
Initialization of 2D Array in C
In the 1D array, we don't need to specify the size of the
array if the declaration and initialization are being done
will
have
to
-
simultaneously
...
We
define
at
least
the
second dimension of the
array
...
HI
1
...
#include
int main(){
3
...
int arr[4][3]={{1,2,3},{2,3,4},{3,4,5},{4,5,6}};
5
...
for(i=0;i<4;i++){
7
...
printf("arr[%d] [%d] = %d \n",i,j,arr[i][j]);
9
...
}//end of i
C - LANGUAGE
185
HI - TECH COMPUTERS
11
...
}
Output
arr[0][0] = 1
arr[0][1] = 2
arr[0][2] = 3
arr[1][0] = 2
arr[1][1] = 3
TE
CH
arr[1][2] = 4
arr[2][0] = 3
arr[2][1] = 4
arr[2][2] = 5
arr[3][0] = 4
arr[3][1] = 5
arr[3][2] = 6
C 2D array example: Storing elements in a matrix and printing
it
...
#include
void main ()
3
...
for (i=0;i<3;i++)
HI
4
...
{
7
...
{
9
...
11
...
}
13
...
\n");
14
...
{
16
...
for (j=0;j<3;j++)
18
...
printf("%d\t",arr[i][j]);
20
...
22
...
C - LANGUAGE
187
HI - TECH COMPUTERS
Return an Array in C
An array is a type of data structure that stores a fixed-size
of a homogeneous collection of data
...
For example, if we want to declare 'n' number of variables,
n1, n2
...
, if we create all these variables individually,
then it becomes a very tedious task
...
Each element of an
TE
CH
array can be accessed using an index of the element
...
Passing array to a function
1
...
h>
2
...
{
printf("Elements of array are : ");
5
...
{
-
4
...
printf("%d ", arr[i]);
8
...
}
int main()
HI
10
...
{
12
...
getarray(arr);
14
...
}
In the above program, we have first created the array arr[]
and then we pass this array to the function getarray()
...
C - LANGUAGE
188
array
HI - TECH COMPUTERS
TE
CH
Output
Passing array to a function as a pointer
Now, we will see how to pass an array to a function as a
pointer
...
#include
void printarray(char *arr)
3
...
for(int i=0;i<5;i++)
6
...
-
4
...
}
9
...
11
...
char arr[5]={'A','B','C','D','E'};
13
...
return 0;
15
...
The function printarray() prints the elements of an
array
...
How to return an array from a function
Returning pointer pointing to the array
1
...
h>
2
...
{
int arr[5];
5
...
for(int i=0;i<5;i++)
7
...
8
...
10
...
}
12
...
{
14
...
n=getarray();
16
...
for(int i=0;i<5;i++)
18
...
20
...
22
...
It
returns
a
local
variable,
but
it is an illegal
memory location to be returned, which is allocated within a
function in the stack
...
Therefore, we can say that this program is returning
TE
CH
memory location, which is already de-allocated, so the output
of the program is a segmentation fault
...
For example, consider a function which sorts the 10 elements
in ascending order
...
Here,
instead of declaring 10 different numbers and then passing
into the function, we can declare and initialize an array and
that
into
the
function
...
As we know that the array_name contains the address of the
first element
...
The array defined as the formal parameter
will automatically refer to the array specified by the array
name defined as an actual parameter
...
#include
int minarray(int arr[],int size){
3
...
int i=0;
5
...
if(min>arr[i]){
7
...
}
9
...
return min;
11
...
13
...
int i=0,min=0;
15
...
17
...
printf("minimum number is %d \n",min);
19
...
}
Output
HI
-
TE
CH
minimum number is 3
C - LANGUAGE
193
HI - TECH COMPUTERS
C Pointers
The
pointer
in
C
language
is
a
variable which stores the
address of another variable
...
The size of the
pointer
depends
on
the
architecture
...
Consider
the
following
example
to
define
a
pointer
which
1
...
2
...
Declaring a pointer
The pointer in c language can be declared using * (asterisk
symbol)
...
as
indirection
pointer
used
to
1
...
char *c;//pointer to char
Pointer Example
given below
...
e
...
The
value
of
HI
number variable is 50
...
By the help of * (indirection operator), we can print the
value of pointer variable p
...
C - LANGUAGE
194
above
HI - TECH COMPUTERS
1
...
h>
2
...
int number=50;
4
...
p=&number;//stores the address of number variable
6
...
TE
CH
7
...
8
...
}
Output
Address of number variable is fff4
Address of p variable is fff4
-
Value of p variable is 50
Pointer to array
1
...
int
*p[10]=&arr;
//
Variable
p
of
type
pointer
is
HI
pointing to the address of an integer array arr
...
void show (int);
2
...
and
used
with
arrays, structures, and functions
...
C - LANGUAGE
195
HI - TECH COMPUTERS
3) It makes you able to access any memory location in the
computer's memory
...
1) Dynamic memory allocation
In
c
language,
we
can
dynamically
allocate
memory
using
malloc() and calloc() functions where the pointer is used
...
It
TE
CH
Pointers in c language are widely used in arrays, functions,
reduces
performance
...
But, we need to use %u to display the address of a variable
...
#include
int main(){
3
...
printf("value
%u",number,&number);
5
...
}
HI
Output
value of number is 50, address of number is fff4
NULL Pointer
A pointer that is not assigned any value but NULL is known as
the
NULL
pointer
...
It will provide a better approach
...
Pointer
Program
to
swap two numbers without using the 3rd
variable
...
#include
int main(){
3
...
5
...
*p1=*p1+*p2;
7
...
*p1=*p1-*p2;
10
...
return 0;
12
...
printf("\nAfter swap: *p1=%d *p2=%d",*p1,*p2);
Before swap: *p1=10 *p2=20
HI
-
After swap: *p1=20 *p2=10
C - LANGUAGE
197
HI - TECH COMPUTERS
C Double Pointer (Pointer to Pointer)
As we know that, a pointer is used to store the address of a
variable in C
...
However,
In C, we can also define a pointer to store the
address of another pointer
...
The first pointer is used to
store the address of a variable whereas the second pointer is
used
to
store
the
address
of
the
first
pointer
...
The syntax of declaring a double pointer is given below
...
int **p; // pointer to a pointer which is pointing to an
integer
...
-
1
...
h>
2
...
{
int a = 10;
5
...
6
...
p = &a; // pointer p is pointing to the address of a
8
...
printf("address of a: %x\n",p); // Address of a will
be printed
10
...
printf("value stored at p: %d\n",*p); // value
stoted at the address contained by p i
...
10 will be
printed
C - LANGUAGE
198
HI - TECH COMPUTERS
12
...
}
Output
address of a: d26a8734
address of p: d26a8738
value stored at pp: 10
C double pointer example
TE
CH
value stored at p: 10
Let's see an example where one pointer points to the address
-
of another pointer
...
1
...
h>
2
...
int number=50;
4
...
int **p2;//pointer to pointer
6
...
p2=&p;
8
...
printf("Address of p variable is %x \n",p);
C - LANGUAGE
199
HI - TECH COMPUTERS
10
...
printf("Address of p2 variable is %x \n",p2);
12
...
return 0;
14
...
However, as we know that pointer
contains the address, the result of an arithmetic operation
performed on the pointer will also be a pointer if the other
operand
is
of
type
integer
...
Following
arithmetic
operations
are
● Increment
● Decrement
● Addition
● Subtraction
Incrementing Pointer in C
If
we
increment
pointing
to
the
a
on
the
pointer
in
C
TE
CH
language:
possible
pointer
immediate
by
next
1,
the
pointer
location
...
We can traverse an array by using the increment operation on a
pointer
which
will
keep
pointing
to
every
element
of
the
HI
array, perform some operation on that, and update itself in a
loop
...
new_address= current_address + i * size_of(data type)
Where i is the number by which the pointer get increased
...
64-bit
For 64-bit int variable, it will be incremented by 4 bytes
...
C - LANGUAGE
201
on
HI - TECH COMPUTERS
1
...
h>
2
...
int number=50;
4
...
p=&number;//stores the address of number variable
6
...
p=p+1;
\n",p);
//
in
increment:
our
bytes
...
return 0;
10
...
printf("After
Address of p variable is 3214864300
After increment: Address of p variable is 3214864304
Decrementing Pointer in C
Like increment, we can decrement a pointer variable
...
The formula of decrementing the pointer is given
below:
1
...
64-bit
For 64-bit int variable, it will be decremented by 4 bytes
...
1
...
h>
2
...
int number=50;
4
...
p=&number;//stores the address of number variable
C - LANGUAGE
202
on
HI - TECH COMPUTERS
6
...
p=p-1;
8
...
9
...
The formula of
adding value to pointer is given below:
1
...
64-bit
-
For 64-bit int variable, it will add 4 * number
...
HI
1
...
h>
2
...
int number=50;
4
...
p=&number;//stores the address of number variable
6
...
p=p+3;
//adding 3 to pointer variable
8
...
return 0;
10
...
But after
adding
3
with
increment
...
e
...
But if we were using 32-bit architecture, it
incrementing
to
6 only, i
...
, 2*3=6
...
C Pointer Subtraction
Like
pointer
addition,
we
can
subtract
a
value
from
the
pointer variable
...
The formula of subtracting value from the
pointer variable is given below:
1
...
64-bit
For 64-bit int variable, it will subtract 4 * number
...
1
...
h>
2
...
int number=50;
4
...
p=&number;//stores the address of number variable
6
...
p=p-3; //subtracting 3 from pointer variable
8
...
return 0;
10
...
TE
CH
However, instead of subtracting a number, we can also subtract
an address from another address (pointer)
...
It will not be a simple arithmetic operation, but it
will follow the following rule
...
For example, if we declare the int pointer, then
this int pointer cannot point to the float variable or some
-
other type of variable, i
...
, it can point to only int type
variable
...
A pointer to void means a generic pointer that can point to
any data type
...
Syntax of void pointer
1
...
According to C perception, the
representation of a pointer to void is the same as the pointer
C - LANGUAGE
205
HI - TECH COMPUTERS
of character type
...
Let's look at the below example:
1
...
h>
2
...
{
4
...
int *p
6
...
float *fp = NULL;//float pointer
8
...
printf("size of void pointer = %d\n\n",sizeof(ptr));
TE
CH
10
...
printf("size
%d\n\n",sizeof(p));
12
...
printf("size
of
-
%d\n\n",sizeof(cp));
14
...
printf("size
of
float
pointer
%d\n\n",sizeof(fp));
return 0;
HI
16
...
}
Output
C - LANGUAGE
206
=
HI - TECH COMPUTERS
What is a Null Pointer?
A Null Pointer is a pointer that does not point to any memory
location
...
The null
pointer basically stores the Null value while void is the type
of the pointer
...
Here, Null means that the pointer is
referring to the 0th memory location
...
When a NULL value
is assigned to the pointer, then it is considered as a Null
pointer
...
● It is used to perform error handling with pointers before
-
dereferencing the pointers
...
Let's look at the situations where we need to use the null
pointer
...
1
...
h>
2
...
{
4
...
printf("Address: %d", ptr); // printing the value of
ptr
...
printf("Value:
%d",
*ptr);
//
dereferencing
the
illegal pointer
7
...
}
In the above code, we declare the pointer variable *ptr, but
it
does
not
contain
the
address
of
any
variable
...
TE
CH
According to the stack memory concept, the local variables of
a function are stored in the stack, and if the variable does
not contain any value, then it shows the garbage value
...
Therefore,
we
can
say
that
keeping
an
uninitialized pointer in a program can cause serious harm to
the computer
...
A
-
null pointer is a pointer pointing to the 0th memory location,
which is a reserved memory and cannot be dereferenced
...
#include
int main()
HI
3
...
int *ptr=NULL;
5
...
{
7
...
}
9
...
{
11
...
}
13
...
return 0;
}
C - LANGUAGE
208
HI - TECH COMPUTERS
In the above code, we create a pointer *ptr and assigns a NULL
value to the pointer, which means that it does not point any
variable
...
C - LANGUAGE
209
HI - TECH COMPUTERS
C Strings
The
string
can
be defined as the one-dimensional array of
characters terminated by a null ('\0')
...
Each character in the array occupies one byte of
memory,
and
the
last
character
must
always
be
0
...
When we
a
string
as
char
s[10],
the
character
s[10]
TE
CH
define
is
implicitly initialized with the null in the memory
...
1
...
By string literal
Let's see the example of declaring string by char array in C
language
...
char ch[10]={'j', 'a', 'v', 'a', '\0'};
As
we
know,
array
index
starts
from
0,
so
it
will
be
-
represented as in the figure given below
...
So we can write
the above code as given below:
1
...
For example:
1
...
Difference between char array and string literal
There are two main differences between char array and literal
...
C - LANGUAGE
210
HI - TECH COMPUTERS
● The string literal cannot be reassigned to another set of
characters whereas, we can reassign the characters of the
array
...
The '%s' is used as a format specifier for the
1
...
h>
2
...
h>
3
...
5
...
char ch[11]={'j', 'a', 'v', 'a', '\0'};
char ch2[11]="java";
6
...
printf("Char Array Value is: %s\n", ch);
8
...
return 0;
10
...
h
...
C gets() function
The gets() function enables the user to enter some characters
followed by the enter key
...
The null character is
user
to
enter
the
TE
CH
added to the array to make it a string
...
It
returns
the
string entered by the user
...
char[] gets(char[]);
Reading string using gets()
1
...
h>
2
...
{
char s[30];
5
...
gets(s);
7
...
8
...
It suffers from buffer
overflow, which can be avoided by using fgets()
...
Consider the following example
...
#include
void main()
3
...
char str[20];
5
...
fgets(str, 20, stdin);
7
...
}
TE
CH
Output
Enter the string? java is the best
java is the best
C puts() function
The puts() function is very much similar to printf() function
...
The puts() function returns an integer value representing the
number of characters being printed on the console
...
HI
Declaration
1
...
1
...
h>
2
...
h>
3
...
char name[50];
5
...
gets(name); //reads string from user
7
...
puts(name);
C - LANGUAGE
//displays string
213
HI - TECH COMPUTERS
9
...
}
Output:
Enter your name: Ram
HI
-
TE
CH
Your name is: Ram
C - LANGUAGE
214
HI - TECH COMPUTERS
C String Functions
There
are
many
important
string
functions
defined
"string
...
No
Function
Description
strlen(string_name)
returns
...
copies
the
contents
of
source
string to destination string
...
The result
of the string is stored in first
string
...
If both strings
-
are same, it returns 0
...
6)
strlwr(string)
returns
HI
5)
7)
strupr(string)
C - LANGUAGE
string
characters
in
characters
in
lowercase
...
215
in
HI - TECH COMPUTERS
C String Length: strlen() function
The strlen() function returns the length of the given string
...
1
...
h>
2
...
h>
3
...
char ch[20]={'j', 'a', 'v', 'a', '\0'};
printf("Length of string is: %d",strlen(ch));
6
...
}
Output:
Length of string is: 4
C Copy String: strcpy()
The
strcpy(destination,
string in destination
...
#include
source)
function
copies
the
source
2
...
h>
-
3
...
char ch[20]={'j', 'a', 'v', 'a', '\0'};
char ch2[20];
6
...
printf("Value of second string is: %s",ch2);
HI
5
...
return 0;
9
...
1
...
h>
2
...
h>
3
...
char ch[10]={'h', 'e', 'l', 'l', 'o', '\0'};
5
...
strcat(ch,ch2);
7
...
return 0;
9
...
Here, we are using gets() function which reads string from the
console
...
h>
#include
Let's see a simple example of strrev() function
...
#include
#include
int main(){
char str[20];
5
...
gets(str);//reads string from console
7
...
printf("\nReverse String is: %s",strrev(str));
9
...
}
Output:
Enter string: java
String is: java
Reverse String is: avaj
TE
CH
4
...
Let's see a simple example of strlwr() function
...
#include
#include
int main(){
4
...
printf("Enter string: ");
6
...
printf("String is: %s",str);
8
...
return 0;
10
...
Let's see a simple example of strupr() function
...
#include
#include
int main(){
char str[20];
5
...
gets(str);//reads string from console
7
...
printf("\nUpper String is: %s",strupr(str));
9
...
}
Output:
Enter string: java
String is: java
Upper String is: JAVA
TE
CH
4
...
It is used to
return substring from first match till the last character
...
char *strstr(const char *string, const char *match)
String strstr() parameters
string: It represents the full string from where substring
will be searched
...
1
...
h>
2
...
h>
3
...
char str[100]="this is java with c and java";
5
...
sub=strstr(str,"java");
7
...
return 0;
9
...
h> header file
...
h> header file contains various methods for performing
mathematical operations such as sqrt(), pow(), ceil(), floor()
etc
...
h header file
...
1)
TE
CH
used functions of math
...
greater
than
given
or
number
...
2)
floor(number)
rounds
returns
down
the
the
given
integer
number
...
sqrt(number)
returns
the
square
root
of
given
HI
number
...
exponent)
5)
abs(number)
C - LANGUAGE
returns the absolute value of given
number
...
h
header file
...
#include
#include
int main(){
4
...
6));
5
...
3));
TE
CH
6
...
6));
7
...
2));
8
...
printf("\n%f",sqrt(7));
10
...
printf("\n%f",pow(3,3));
12
...
14
...
000000
4
...
000000
HI
3
...
000000
2
...
000000
27
...
Each element of
a structure is called a member
...
Let's see
TE
CH
the syntax to define the structure in c
...
struct structure_name
2
...
data_type member1;
4
...
...
...
data_type memeberN;
8
...
1
...
char name[20];
4
...
{
5
...
There are two ways
to declare structure variable:
1
...
By
declaring
a
variable
at
the
time
of
defining
structure
...
It
should
be
declared
within
the
main
function
...
struct employee
2
...
char name[50];
4
...
};
TE
CH
Now write given code inside the main() function
...
struct employee e1, e2;
The
variables e1 and e2 can be used to access the values
stored in the structure
...
2nd way:
Let's
see
another
way
defining the structure
...
struct employee
int id;
3
...
float salary;
5
...
{
to
Which approach is good
HI
If number of variables are not fixed, use the 1st approach
...
If no
...
It saves your
code to declare a variable in main() function
...
By
...
By -> (structure pointer operator)
Let's see the code to access the id member of p1 variable by
...
1
...
id
C - LANGUAGE
224
HI - TECH COMPUTERS
C Structure example
Let's see a simple example of structure in C language
...
#include
#include
struct employee
4
...
char name[50];
//declaring e1 variable for structure
7
...
{
9
...
}e1;
//store first employee information
10
...
id=101;
11
...
name, "Ram");//copying string into char
array
12
...
printf( "employee 1 id : %d\n", e1
...
printf( "employee 1 name : %s\n", e1
...
}
Output:
-
15
...
1
...
h>
2
...
h>
3
...
{
int id;
5
...
float salary;
//declaring e1 and e2 variables for structure
8
...
{
TE
CH
7
...
//store first employee information
11
...
id=101;
12
...
name, "Ram");//copying string into char
array
13
...
salary=56000;
14
...
//store second employee information
e2
...
strcpy(e2
...
e2
...
19
...
21
...
id);
22
...
name);
23
...
salary);
24
...
//printing second employee information
26
...
id);
27
...
name);
28
...
salary);
29
...
}
Output:
C - LANGUAGE
226
HI - TECH COMPUTERS
employee 1 id : 101
employee 1 name : Ram
employee 1 salary : 56000
...
000000
C - LANGUAGE
227
HI - TECH COMPUTERS
typedef in C
The typedef is a keyword used in C programming to provide some
meaningful names to the already existing variable in the C
program
...
In short, we can say that this keyword is used to
redefine the name of an already existing variable
...
typedef
In the above syntax, 'existing_name' is the name of an already
existing variable while 'alias name' is another name given to
the existing variable
...
To
overcome
the
problem, we use a typedef keyword
...
typedef unsigned int unit;
-
In the above statements, we have declared the unit variable of
type unsigned int by using a typedef keyword
...
unit a, b;
instead of writing:
1
...
This keyword is useful when we are dealing
with the long data type especially, structure declarations
...
1
...
h>
2
...
{
4
...
unit i,j;
6
...
j=20;
TE
CH
8
...
printf("\nValue of j is :%d",j);
10
...
}
Output
Value of i is :10
Value of j is :20
Using typedef with structures
Consider the below structure declaration:
-
1
...
{
3
...
int age;
HI
5
...
struct student s1;
In
the
above
structure
declaration,
we
have
created
the
variable of student type by writing the following statement:
1
...
e
...
To
avoid
such
a big
statement, we use the typedef keyword to create the variable
of type student
...
struct student
2
...
char name[20];
4
...
};
6
...
stud s1, s2;
TE
CH
In the above statement, we have declared the variable stud of
type struct student
...
The above typedef can be written as:
1
...
{
3
...
int age;
5
...
stud s1,s2;
-
From the above declarations, we conclude that typedef keyword
reduces the length of the code and complexity of data types
...
Let's
see
another
example
where
we
typedef
the
structure
HI
declaration
...
#include
typedef struct student
3
...
char name[20];
5
...
}stud;
7
...
{
9
...
printf("Enter the details of student s1: ");
11
...
scanf("%s",&s1
...
printf("\nEnter the age of student:");
14
...
age);
15
...
name);
16
...
age);
17
...
}
Output
TE
CH
Enter the details of student s1:
Enter the name of the student: Peter
Enter the age of student: 28
Name of the student is : Peter
HI
-
Age of the student is : 28
C - LANGUAGE
231
HI - TECH COMPUTERS
C Array of Structures
Consider
a
case,
where
we
need
to
store
the
data
of
5
students
...
1
...
h>
2
...
char name[20];
5
...
float marks;
7
...
void main()
9
...
{
10
...
int dummy;
12
...
name,&s1
...
marks);
14
...
-
13
...
name,&s2
...
marks);
17
...
18
...
scanf("%s %d %f",s3
...
id,&s3
...
scanf("%c",&dummy);
21
...
\n");
22
...
name,s1
...
marks);
23
...
name,s2
...
marks);
24
...
name,s3
...
marks);
25
...
James 90 90
...
000000
Nick 90 90
...
be
increased if there are 20 students
...
This
will
always
be
tough
since
we
will
have to
declare a variable every time we add a student
...
However, c enables us to declare an array of structures by
using which, we can avoid declaring the different structure
variables; instead we can make a collection containing all the
structures that store the information of different entities
...
The array of structures
HI
in C are used to store information about multiple entities of
different data types
...
C - LANGUAGE
233
HI - TECH COMPUTERS
Let's see an example of an array of structures that stores
information of 5 students and prints it
...
#include
#include
struct student{
4
...
char name[10];
7
...
int i;
TE
CH
6
...
struct student st[5];
printf("Enter Records of 5 students");
11
...
printf("\nEnter Rollno:");
13
...
rollno);
14
...
scanf("%s",&st[i]
...
}
17
...
for(i=0;i<5;i++){
19
...
rollno,st[i]
...
}
-
10
...
22
...
For example, we may need to store the address of an
entity employee in a structure
...
Hence, to store the address of the employee, we need to store
the address of the employee into a separate structure and nest
the following program
...
#include
struct address
3
...
char city[20];
5
...
char phone[14];
TE
CH
the structure address into the structure employee
...
};
-
8
...
{
10
...
struct address add;
};
HI
12
...
void main ()
14
...
struct employee emp;
16
...
scanf("%s
%s
%d
%s",emp
...
add
...
add
...
add
...
printf("Printing the employee information
...
printf("name: %s\nCity: %s\nPincode: %d\nPhone:
%s",emp
...
add
...
add
...
add
...
}
C - LANGUAGE
236
HI - TECH COMPUTERS
Output
Enter employee information?
Arun
Delhi
110001
1234567890
Printing the employee information
...
The union
statement defines a new data type with more than one member
for your program
...
member definition;
TE
CH
member definition;
} [one or more union variables];
The union tag is optional and each member definition is a
normal variable definition, such as int i; or float f; or any
other valid variable definition
...
Here is the way you
f, and str −
union Data {
-
would define a union type named Data having three members i,
int i;
HI
float f;
char str[20];
} data;
Now,
a
variable
of
Data
type
can
store
an
integer,
a
floating-point number, or a string of characters
...
e
...
You can use any built-in or user
defined data types inside a union based on your requirement
...
For example, in the above
example,
Data
C - LANGUAGE
type
will
occupy
20
bytes
of
memory
238
space
HI - TECH COMPUTERS
because this is the maximum space which can be occupied by a
character
string
...
h>
#include
Sometimes,
it
is
not
enough to only display the data on the console
...
However, if we need to do so,
TE
CH
we may store it onto the local file system which is volatile
and can be accessed every time
...
File handling in C enables us to create, update, read, and
delete the files stored on the local file system through our C
program
...
● Creation of the new file
● Opening an existing file
● Reading from the file
● Writing to the file
-
● Deleting the file
Functions for file handling
There
are
many
functions
in
the
C
library to open, read,
HI
write, search and close the file
...
C - LANGUAGE
241
HI - TECH COMPUTERS
We can use one of the following modes in the fopen() function
...
It sends formatted output to a stream
...
int fprintf(FILE *stream, const char *format [, argument,
...
#include
main(){
TE
CH
Example:
3
...
fp = fopen("file
...
fprintf(fp, "Hello file by fprintf
...
fclose(fp);//closing file
7
...
It reads a word from the file and returns EOF at the end
of file
...
int fscanf(FILE *stream, const char *format [, argument,
...
#include
main(){
3
...
FILE *fp;
char buff[255];//creating char array to store data of
file
5
...
txt", "r");
6
...
printf("%s ", buff );
8
...
10
...
C File Example: Storing employee information
Let's
see
a
file
handling
example
to
store
employee
information as entered by user from console
...
#include
void main()
3
...
4
...
int id;
6
...
float salary;
8
...
txt", "w+");/*
9
...
open for writing */
11
...
return;
}
14
...
15
...
fprintf(fptr, "Id= %d\n", id);
17
...
scanf("%s", name);
19
...
printf("Enter the salary\n");
21
...
fprintf(fptr, "Salary= %
...
fclose(fptr);
24
...
For windows operating
TE
CH
system, go to TC\bin directory, you will see emp
...
It
will have following information
...
txt
Id= 1
Name= sonoo
HI
-
Salary= 120000
C - LANGUAGE
245
HI - TECH COMPUTERS
C fputc() and fgetc()
Writing File : fputc() function
The fputc() function is used to write a single character into
file
...
Syntax:
1
...
main(){
TE
CH
1
...
h>
3
...
fp = fopen("file1
...
fputc('a',fp);//writing single character into file
6
...
}
file1
...
It gets a character from the stream
...
Syntax:
HI
1
...
#include
#include
void main(){
4
...
char c;
6
...
fp=fopen("myfile
...
9
...
printf("%c",c);
C - LANGUAGE
246
HI - TECH COMPUTERS
11
...
fclose(fp);
13
...
}
myfile
...
Let's see examples of writing and
reading file using fgets() and fgets() functions
...
It
outputs string to a stream
...
int fputs(const char *s, FILE *stream)
Example:
-
1
...
h>
2
...
h>
3
...
FILE *fp;
HI
5
...
7
...
txt","w");
8
...
10
...
getch();
12
...
txt
hello c programming
C - LANGUAGE
247
HI - TECH COMPUTERS
Reading File : fgets() function
The fgets() function reads a line of characters from file
...
Syntax:
1
...
#include
void main(){
4
...
char text[300];
6
...
TE
CH
2
...
h>
8
...
txt","r");
9
...
fclose(fp);
12
...
}
Output:
-
11
...
No
Macro
Description
_DATE_
represents
...
represents current time in "HH:MM:SS"
format
...
4
_LINE_
represents current line number
...
c
1
...
h>
2
...
printf("Date :%s\n", __DATE__ );
5
...
printf("Line :%d\n", __LINE__ );
7
...
8
...
c
Date :Dec 6 2015
Time :12:28:46
Line :6
C - LANGUAGE
249
HI - TECH COMPUTERS
C Expressions
An expression is a formula in which operands are linked to
each other by the use of operators to compute a value
...
Let's see an example:
1
...
There are four types of expressions exist in C:
● Arithmetic expressions
● Relational expressions
● Logical expressions
● Conditional expressions
Each type of expression takes certain types of operands and
uses a specific set of operators
...
For example:
-
1
...
The
HI
portion after the equal is an expression
...
An arithmetic expression
computes a value of type int, float or double
...
TE
CH
contains both integral and real operands, it is known as mixed
public class ArithmeticExceptionTest {
public static void main(String[] args) {
int a = 0, b = 10;
int c = b/a;
System
...
println("Value of c is : "+ c);
}
}
-
Relational Expressions
● A relational expression is an expression used to compare
two operands
...
● In
relational
expressions,
a
numeric
value
cannot
be
compared with the string value
...
Here,
the
zero
value
is
equivalent to a false and non-zero value is equivalent to
true
...
The
relational
expression results in value 1 if x is an even
number otherwise results in value 0
...
This relational expression results in 1 if
a is not equal to b otherwise 0
...
a>=9
It is used to check whether the value of a is
HI
-
greater than or equal to 9
...
#include
int main()
3
...
5
...
if(x%2==0)
7
...
}
TE
CH
8
...
else
11
...
return 0;
13
...
● It is a complex test condition to take a decision
...
Logical
Description
Expressions
It is a test condition to check whether the
( x < 6 )
x is greater than 4 and x is less than 6
...
x > 10 || y
It is a test condition used to check whether
<11
x is greater than 10 or y is less than 11
...
It is a test condition used to check whether
&& ( y = = 2
x is not greater than 10 and y is equal to
)
-
! ( x > 10 )
2
...
C - LANGUAGE
254
HI - TECH COMPUTERS
Let's see a simple program of "&&" operator
...
#include
int main()
3
...
int x = 4;
5
...
if ( (x <10) && (y>5))
7
...
}
TE
CH
8
...
else
11
...
return 0;
13
...
#include
int main()
3
...
int x = 4;
5
...
if ( (x <6) || (y>10))
7
...
}
TE
CH
8
...
else
11
...
return 0;
13
...
● A
conditional
operator
is
also
known
as
a
ternary
operator
...
exp1 ? exp2 : exp3
above
expression
is
a
conditional
expression
which
TE
CH
The
is
evaluated on the basis of the value of the exp1 expression
...
Let's understand through a simple example
...
#include
#include
int main()
4
...
char status;
7
...
if(status == 'M')
9
...
10
...
printf("Unmarried");
12
...
}
Output
C - LANGUAGE
257
HI - TECH COMPUTERS
Factorial Program in C
Factorial Program in C: Factorial of n is the product of all
positive descending integers
...
For example:
1
...
3! = 3*2*1 = 6
Here, 5! is pronounced as "5 factorial", it is also called "5
bang" or "5 shriek"
...
There
are
many
ways
to
write
the
factorial
program
in
c
language
...
Exception Handling in Java - Java
● Factorial Program using loop
● Factorial Program using recursion
Factorial Program using loop
Let's see the factorial Program using loop
...
#include
int main()
3
...
int i,fact=1,number;
5
...
7
...
9
...
printf("Factorial of %d is: %d",number,fact);
11
...
}
Output:
Enter a number: 5
Factorial of 5 is: 120
C - LANGUAGE
258
HI - TECH COMPUTERS
Factorial Program using recursion in C
Let's see the factorial program in c using recursion
...
#include
3
...
if (n == 0)
6
...
else
8
...
{
return(n * factorial(n-1));
9
...
11
...
{
13
...
long fact;
15
...
scanf("%d", &number);
-
17
...
fact = factorial(number);
19
...
return 0;
}
HI
21
...
There
are two common ways to swap two numbers without using third
variable:
1
...
By * and /
Program 1: Using + and third variable
...
#include
int main()
3
...
int a=10, b=20;
TE
CH
Let's see a simple c example to swap two numbers without using
5
...
a=a+b;//a=30 (10+20)
7
...
a=a-b;//a=20 (30-10)
-
9
...
return 0;
11
...
1
...
h>
2
...
h>
3
...
{
5
...
printf("Before swap a=%d b=%d",a,b);
7
...
b=a/b;//b=10 (200/20)
9
...
system("cls");
11
...
return 0;
13
...
In this program, we are getting number as input
from the user and reversing that number
...
1
...
h>
2
...
{
TE
CH
4
...
printf("Enter a number: ");
6
...
while(n!=0)
8
...
rem=n%10;
10
...
n/=10;
12
...
printf("Reversed Number: %d",reverse);
return 0;
15
...
Enter a number: 123
HI
Reversed Number: 321
C - LANGUAGE
262
HI - TECH COMPUTERS
Prime number
Prime number in C: Prime number is a number that is greater
than
1 and divided by 1 or itself
...
For example 2, 3, 5, 7, 11, 13, 17, 19, 23
...
#include
h>
printf("Enter the Number: ");
scanf("%d",&n);
HI
-
if(n==0 || n==1)
{
printf("it is not Prime Number
...
For example 121, 34543, 343, 131, 48984
are the palindrome numbers
...
In this c program, we
will get an input from the user and check whether number is
palindrome or not
...
#include
int main()
3
...
int n,r,sum=0,temp;
-
5
...
scanf("%d",&n);
7
...
while(n>0)
HI
9
...
r=n%10;
11
...
n=n/10;
13
...
if(temp==sum)
15
...
else
17
...
return 0;
19
...
Armstrong number is a number that is equal to the sum of cubes
of its digits
...
Let's try to understand why 153 is an Armstrong number
...
where:
3
...
(5*5*5)=125
5
...
So:
7
...
153 = (1*1*1)+(5*5*5)+(3*3*3)
Let's try to understand why 371 is an Armstrong number
...
371 = (3*3*3)+(7*7*7)+(1*1*1)
-
2
...
(3*3*3)=27
4
...
(1*1*1)=1
HI
6
...
27+343+1=371
Let's see the c program to check Armstrong Number in C
...
#include
int main()
3
...
int n,r,sum=0,temp;
5
...
scanf("%d",&n);
7
...
while(n>0)
9
...
r=n%10;
11
...
n=n/10;
13
...
if(temp==sum)
15
...
else
17
...
return 0;
19
...
In this program, we are taking input from the user and
iterating this number until it is 0
...
1
...
h>
2
...
h>
3
...
long int n,sum=0,r;
5
...
6
...
scanf("%ld",&n);
8
...
{
r=n%10;
11
...
n=n/10;
13
...
n=sum;
15
...
16
...
r=n%10;
18
...
{
20
...
printf("one ");
22
...
case 2:
24
...
break;
26
...
break;
29
...
printf("four ");
31
...
case 5:
33
...
break;
35
...
printf("six ");
37
...
case 7:
39
...
break;
41
...
printf("eight ");
43
...
case 9:
45
...
break;
47
...
printf("zero ");
49
...
TE
CH
HI - TECH COMPUTERS
50
...
printf("tttt");
52
...
}
54
...
}
56
...
}
Output:
enter the number=4321
four three two one
C - LANGUAGE
269
HI - TECH COMPUTERS
HR Interview Questions | Common Interview Questions
A list of frequently asked HR interview questions or Common
interview questions or Job interview questions and answers are
given below
...
This
puts
all
the
pressure
on
the
candidate,
and
TE
CH
question
interviewer relax
...
You should
start with an easy and confident tone and answer in a proper
manner
...
Always remember, you are
not giving the interview to a robot so your articulation, your
pronunciation of each word should be clear and confident
...
-
First of all, thank you for giving me this opportunity to
introduce myself
...
As far as my education qualification is concerned, I have done
with
finance
HI
MBA
stream
from
Srivenkateswara university in
Emerald's P
...
College, Tirupathi, in the year of 2014
...
tech from N
...
T Jaipur in 2012
...
I
...
Allahabad
...
My
father
is
a
Businessman,
and
my
Mother
is
a
homemaker
...
I am good in programming languages C, C++, and Java and very
much interested in HTML, CSS, ASP
...
My strength is self-confidence, positive attitude, hard work
...
C - LANGUAGE
270
HI - TECH COMPUTERS
My hobbies are: Watching news channels, Playing volleyball,
Listening to music
...
I am Anshika Bansal
...
I
have
done
my
B
...
coming
including
to
my
family
members,
there
are
4
members
TE
CH
While
me
...
My younger sister will appear her 12th CBSE board
exam this year
...
I
am
a
cool
hearted
person,
so usually see every
difficulty with a positive side and keep myself always smiling
which makes me stronger even more
...
My
hobbies
are
dancing,
Internet
surfing,
playing
Chess,
-
listening to music, watching the news channel
...
HI
Thank you for giving this opportunity to introduce myself
...
I am Anshika Bansal
...
I
have
done
my
B
...
I
am
carrying
5
years
of
experience
top
Street
Companies
...
I
can
survive
fast-paced environment
...
2) Why are you applying for this job? (or)
Why this role attract you?
By this question, the interviewer wants to know that:
● If you fully understand what the job entails
TE
CH
● How well you might match their requirement
● What appeals to you most about this job
Before answering this question, take your own time an answer
in
the
way
that
convinces
the
interviewer
...
Possible Answer 1
I have applied for this vacancy because it is an excellent
match for my skills and experience
...
-
Possible Answer 2
Sir, it's a great privilege to work in a reputed company like
yours
...
Through this role, I can show
HI
my technical skills to contribute to the company growth
...
Don't
tell a lie or compromise to get the job only
...
It an extra effort means I am doing something for the
company, I'll be happy to do it
...
The work should always be more
important
than
the
money
...
Possible Answer 1
"Money is always important, but the work is most important for
me
...
If we work and
TE
CH
"I
achieve Company goals then obviously money would follow
...
"
Possible Answer 3
"Work is more important for me
...
My work
makes me stay productive, and money would naturally come along
well
...
It's vital and necessary for us to live and prosper
the
same
time,
it's
not
my single most important
driving force
...
"
HI
5) What do you know about this organization?
You
should
going
for
fully
an
aware of that organization where you are
interview,
so
check
the
history,
present
structure and working style of that organization
...
Possible Answer 1
We
all
know
that
it
is
one
of
the
fastest
growing
infrastructure company in India
...
People feel proud to be the part of your
company
as
the
company
provides
full
support
to
their
employees in professional front
...
It has crossed the branches in the
world also
...
Possible Answer 2
We all know that this company is India's no
...
I was delighted to see on your company website
that your employees are talking about how great it is to work
for your company
...
It's
TE
CH
great to see that your employees are proud to talk about how
much they love their company and jobs
...
Avoid trashing
other
employers
and
making
a
statement
like
"I
need
more
money"
...
I have learned a lot from my last
job, but now I am looking for new challenges to broaden my
-
horizons and to gain a new skill-set
...
HI
Possible Answer 1
"I believe that everyone starts with a beginning, I need a
platform
to
prove
my
abilities
and
skills
...
I need to
be a part of your growth
...
"
Possible Answer 2
"As a fresher, I need a platform to prove my ability
...
None is born with experience,
and if you hire me, I will get professional experience through
your company
...
I am ensuring you that I will put all my
efforts
for
the
good
progress
of
the
organization
...
Being
the
working
punctual
and
TE
CH
regular, I can finish the work giving to me on time and try my
best to fulfill all the needs of the company
...
"
8) What are your salary expectations?
Don't ask your salary in exact numbers, instead of this show
-
your commitment to the job itself
...
As you also know that the high cost of living here
in Delhi
...
Learning and
gaining experience is my major priority
...
Possible Answer 3
As of now, I haven't thought much about it
...
C - LANGUAGE
275
I
am
HI - TECH COMPUTERS
9) Assume you are hired, then how long would you expect to
work for us?
Possible Answer 1
"I will do my best for the growth of your company as long as I
have
the
career
growth,
job
satisfaction,
respect
and
a
healthy environment, then I don't need to change my company
...
"
Possible Answer 3
"Everyone looks for a bright future, healthy work environment,
good salary, job satisfaction and I am pretty sure that your
company
gives
such
things,
company
...
So your company gains
-
good results, and I can be in a good position to improve my
skills
...
That thought will create an interest in learning the
things
...
Possible Answer 2
I will answer this question based on some parameters
...
When it comes
to creativity, I would like to rate myself as 9
...
To talk about patience, I will tag myself with
6 because I am an entry-level professional
...
That
is
probably
why
in
most
companies,
senior
management looks more patient than entry level or even middle
level
...
HI
-
*****
C - LANGUAGE
277
Title: Full C language
Description: All detailed notes of C language with programs and examples
Description: All detailed notes of C language with programs and examples