Computer Science Paper 1 Definitions

GCSE AQA Computer science

Variable

A named storage location in memory that can hold a value which may change during program execution.

Constant

A named value that does not change during program execution.

Assignment

Giving a variable a value using the = symbol (e.g., x = 5).

Sequence

Instructions that are executed one after the other, in order.

Selection

Decision-making using conditions (e.g., if, elif, else).

Iteration

Repeating code (looping), using for or while loops.

Relational Operator (e.g. =, >=)

Used to compare values

Logical Operator

Used to combine or modify Boolean conditions (e.g. and, or)

Arithmetic Operator

Maths operators

Data Type

A data type defines the kind of data a variable can hold and what operations can be performed on it.

Data Structure

A data structure is a way of storing multiple data values under one variable name, often of the same or related types. This allows data to be accessed, searched, and looped through more easily and efficiently.

Algorithm

A sequence of steps/instructions that can be followed to complete a task.

Function

A named block of code that performs a specific task and can be reused.

Parameter

A variable in a function definition.

Argument

The value passed to a function when called.

Return

The value a function sends back after processing.

Syntax Error

Mistake in the structure of the code (e.g., missing parentheses or incorrect punctuation) that prevents the program from compiling or running.

Logic Error

Code runs but behaves incorrectly.

Runtime Error

Error occurs while the program is running (e.g., divide by 0).

Test Data – Normal

Expected, valid input.

Test Data – Boundary

Input at the edge of acceptable ranges. (can be both valid and erroneous)

Test Data – Invalid

Unexpected or incorrect input.