Introduction to Subroutines (AQA GCSE Computer Science)

Revision Note

Test yourself
James Woodhouse

Written by: James Woodhouse

Reviewed by: Lucy Kirkham

Introduction to Subroutines

What is a subroutine? 

  • Subroutines are an out of line block of code that may be called by simply writing their name in a program     

  • Subroutines are given a unique name so they can be called anywhere in a program

  • There are many benefits to using subroutines, these include

    • Making bigger problems easier to break down (decompose) and code

    • Allows team members to be able to work on different parts of a problem

    • Makes the program easier to debug

    • Makes programs more efficient as code is not duplicated

  • More detailed information about subroutines can be found in the 'Structured Programming' section

Meaningful Identifiers

What are meaningful identifiers?

  • Meaningful identifiers are sensible names used for variables, constants or subroutines

  • A meaningful identifier must be used to help aid the maintainability of a program

  • An example would be a variable used for an input of a users' first name

Meaningful Identifier

Poor Identifier

name ← USERINPUT

IF name == "Mike" THEN

cost ← 100 * 0.5

ELSE

OUTPUT name + " your total is: " + cost

a ← USERINPUT

IF a == "Mike" THEN

b ← 100 * 0.5

ELSE

OUTPUT a + " your total is: " + b

Examples of using subroutines

Prgm_Introduction to Subroutines

Last updated:

You've read 0 of your 10 free revision notes

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

James Woodhouse

Author: James Woodhouse

Expertise: Computer Science

James graduated from the University of Sunderland with a degree in ICT and Computing education. He has over 14 years of experience both teaching and leading in Computer Science, specialising in teaching GCSE and A-level. James has held various leadership roles, including Head of Computer Science and coordinator positions for Key Stage 3 and Key Stage 4. James has a keen interest in networking security and technologies aimed at preventing security breaches.

Lucy Kirkham

Author: Lucy Kirkham

Expertise: Head of STEM

Lucy has been a passionate Maths teacher for over 12 years, teaching maths across the UK and abroad helping to engage, interest and develop confidence in the subject at all levels.Working as a Head of Department and then Director of Maths, Lucy has advised schools and academy trusts in both Scotland and the East Midlands, where her role was to support and coach teachers to improve Maths teaching for all.