Programming is a core part of GCSE Computer Science. Revise the key concepts and common mistakes below, then lock them in with the free games.
Key concepts
VariableA named store whose value can change.
ConstantA named store whose value never changes.
IntegerA whole number with no fractional part.
FloatA number with a decimal point, e.g. 3.14.
BooleanA value that is True or False.
StringA sequence of characters, e.g. 'hello'.
FOR loopRepeats a block a fixed number of times.
WHILE loopRepeats while a condition is True.
IF/ELSERuns one block or another based on a test.
FunctionA named block of code that returns a value.
ParameterAn input passed to a function.
Return valueThe value a function gives back to the caller.
ProcedureA named block of code that does not return a value.
Local scopeA variable only visible inside its function.
Common mistakes to avoid
Questions where students often pick the tempting wrong answer — make sure you know the right one:
How do RAM and storage differ?✗ They are the same thing. ✓ RAM is fast, volatile working memory; storage keeps data without power.
What is system software like an operating system for?✗ Doing the user's tasks like writing essays. ✓ Managing hardware and running other software.
Must an algorithm be written in code?✗ Yes, an algorithm has to be program code. ✓ No — it's a step-by-step method (e.g. pseudocode or a flowchart).
What is a primary key?✗ A field that can have duplicate values. ✓ A field that uniquely identifies each record in a table.
What does SQL do?✗ Designs the physical hardware. ✓ Lets you query and manage data in a relational database.
Practise Programming — free games
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