Programming Fundamentals

Data types

Type	Example	Stores
Integer	5	whole number
Real / Float	5.7	decimal
Boolean	True / False	logical
Character	'A'	one symbol
String	"hello"	text

Variables vs constants

• Variable – a named store whose value can change while running.
• Constant – set once, never changes (e.g. VAT = 0.2). Improves readability and safety.

Assignment & casting

age ← 15                 # assignment
price ← float("3.50")    # cast string → real
text  ← str(age)         # cast int → string

Operators

Arithmetic:  +  -  *  /  ^(power)  MOD  DIV
Comparison:  ==  !=  <  >  <=  >=
Boolean:     AND  OR  NOT

• MOD = remainder: 7 MOD 3 = 1
• DIV = integer division: 7 DIV 3 = 2

The three constructs

1. Sequence – steps in order

2. Selection – IF decisions

3. Iteration – loops

Exam tip

MOD (remainder) and DIV (whole part) are heavily tested. 15 MOD 2 = 1 is a common way to test if a number is odd/even.