Variables and Constants

A variable is a named memory location that holds a value which can change during the program's execution. A constant is a named value that cannot change.

In Cambridge pseudocode, assignment uses the ← arrow:

score ← 0          // variable — can change
PI ← 3.14159        // constant — should not change
name ← "Alice"

Rules for identifier names

• Must start with a letter
• Can contain letters, digits, and underscores (no spaces)
• Should be meaningful (e.g., totalScore not x)
• Cambridge pseudocode is case-insensitive for keywords but names are case-sensitive

Data Types

Every variable has a data type that determines what kind of value it can hold and what operations can be performed on it.

Input and Output

Programs communicate with users through input (data coming in) and output (data going out).

// Input — get a value from the user:
INPUT name
INPUT score

// Output — display a value or message:
OUTPUT "Enter your name: "
OUTPUT "Hello, ", name
OUTPUT score

Combining output with variables

name ← "Alice"
score ← 95
OUTPUT "Player: ", name
OUTPUT "Score: ", score
OUTPUT "Player: " & name & " scored " & score

Casting (Converting) Data Types

Sometimes you need to convert between data types. Cambridge pseudocode uses built-in functions:

Declaring Variables (structured pseudocode)

In some Cambridge mark schemes you may see variable declarations:

DECLARE score : INTEGER
DECLARE name : STRING
DECLARE temperature : REAL
DECLARE active : BOOLEAN