Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

be changed during normal execution of the program and the value is variable
...


4
...
7 Define the operators =, ≠,
<, <=, >, >=, mod, div
...
The value is constant
...

An operator is a character/set of characters that represents an action
...

Arithmetic operators (+, -, div, mod) for doing simple mathematical calculations
...

Equality & Relational operators (<, >, >=, <=, ==, !=,
...


Arithmetic operator
+ is used for adding two numbers (also used for String concatenation)
- is used for subtractions
* is used for multiplication
mod: returns the remainder of a division calculation
div: returns the numbers of times X divides into Y without a remainder
/ is used for division in OOP (but cannot be used in Pseudocode)
% is used for mod in OOP (but cannot be used in Pseudocode)
Unary operators
++ : Increment operator; increments a value by 1
I++ : is the same as I = I + 1
-- : Decrement operator; decrements a value by 1
I-- : is the same as I = I -1
Equality and Relational Operators
== : Equal to (only for non-Strings!)
!= or ≠ : Not equal to
> : Greater than
>= : Greater than or equal to
< : Less than
<= : Less than or equal to

4
...
8 Analyse the use of
variables, constants and
operators in algorithms
...
25 and why is an operator required?
When should a variable be used?
Variables should be used when the value of something
needs to be changed
...

When should operators be used?
Operators should be used when the value of a variable
needs to be changed
...
3
...

Construct algorithms using looping and branching
NUM = 5
if num < 3
then output "under 3"
else i
4
...
10 Describe the
characteristics and applications
of a collection
...

of the same type
size is variable
Applications of lists:
The order of elements in a collection is typically not
- Useful for group of items when you don’t know how many items you’ll be
known
needing/using (contrast to arrays where the size is set in stone at creation)
If you don't know the order of elements then you need to
- Because the collection is only as big as you need it to be, it is an efficient use of RAM
store them in a variable size data structure
...

- Can be of any data type (primitive or even your own object)
List is a type of collection
Topic 4 Page 22

List is a type of collection
4
...
11 Construct algorithms
using the access methods of a
collection
...
3
...


A sub-program is a set of computer instructions that perform a specific and predefined
task
...
This is

---