National 5Computer ScienceSQAComputing ScienceRevision Notes1. Software Design & Development (SDD)Implementation (Data Types)Primitive Data Types

Primitive Data Types (SQA National 5 Computing Science): Revision Note

Exam code: X816 75

Written by: Robert Hampton

Reviewed by: James Woodhouse

Updated on 21 October 2025

Primitive data types

What is a data type?

A data type is a classification of data into groups according to the kind of data they represent
Computers use different data types to represent different types of data in a program
The basic data types include:

Data type	Used for	Pseudocode	Example
Integer	Whole numbers	`INTEGER`	`10, -5, 0`
Real	Numbers with a fractional part (decimal)	`REAL`	`3.14, -2.5, 0.0`
Character	Single character	`CHAR`	`'a', 'B', '6', '£'`
String	Sequence of characters	`STRING`	`"Hello world", "ABC", "@#!%"`
Boolean	True or false values	`BOOLEAN`	`True, False`

It is important to choose the correct data type for a given situation to ensure accuracy and efficiency in the program
Data types can be changed within a program, this is called casting

Programming data types

Data type	Pseudocode (SQA style)	Python
Integer	`SET number TO 5`	`number = 5`
Real	`SET realNumber TO 3.14`	`realNumber = 3.14`
Character	`SET firstInitial TO 'A'`	`firstInitial = 'A'`
String	`SET password TO "letmein"`	`password = "letmein"`
Boolean	`SET lightSensor TO True`	`lightSensor = True`

Worked Example

A sports shop requires a program to store information about football boots.

Complete the table below to state which types of variable should be used.

[3]

Variable	Type of variable
`bootBrand`
`availableInStore`
`bootSize`

Answer

Variable	Type of variable
`bootBrand`	String [1 mark]
`availableInStore`	Boolean [1 mark]
`bootSize`	Integer [1 mark]

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