This introduction covers The Storage Boxes within Variables & Constants for GCSE Computer Science. Revise Variables & Constants in 3.2 Programming for GCSE Computer Science with 17 exam-style questions and 10 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 2 of 7 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
The Storage Boxes
Think of computer memory as a warehouse full of boxes. A variable is a labelled box where you can store data - and change what's inside whenever you want. The label (name) stays the same, but contents can change: "score = 10" then later "score = 15". A constant is a sealed box - once you put something in, it can never change. Use constants for things like PI = 3.14159 or VAT_RATE = 0.20.
Practice questions for Variables & Constants
Which of the following best describes a variable in a program?
Explain three reasons why using named constants is considered good programming practice.