Skip to content
VirtusAcademy

Parameters and Return Values

FoundationHigherAQA

Revise Parameters and Return Values for GCSE Computer Science with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA GCSE Computer Science (8525). Parameters pass data into a subroutine, and a return value passes a result back out.

Free downloads

These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA specification. Every worksheet comes with a full mark scheme.

Foundation

WorksheetFoundation · PDFMark SchemeFoundation · PDF

Higher

WorksheetHigher · PDFMark SchemeHigher · PDF

Topic overview

Parameters allow data to be passed into a subroutine, and return values allow data to be passed back out.

A parameter is the variable named in the subroutine definition. An argument is the actual value supplied when the subroutine is called. Defining area(width, height) declares two parameters; calling area(5, 3) supplies two arguments.

Parameters make subroutines reusable. A subroutine that always calculated the area of a 5 by 3 rectangle would be useless; one that takes width and height works for any rectangle. Functions return a value using a RETURN statement, and that value can then be stored in a variable or used directly in an expression.

Revision notes

Parameters and arguments

A parameter is the variable named in the subroutine definition.

An argument is the actual value passed when it is called. area(width, height) has two parameters; area(5, 3) passes two arguments. The terms are distinct and both are examinable.

Why parameters matter

They make a subroutine reusable with different data.

Without parameters a subroutine could only ever work on fixed values. With them, one subroutine handles every case, which is the whole point of writing it separately.

Return values

A function uses RETURN to send a value back to the calling code.

The returned value can be stored — total ← area(5, 3) — or used directly inside a larger expression. A procedure has no RETURN because it sends nothing back.

Key points

  • Parameters pass data into a subroutine.
  • A parameter is named in the definition.
  • An argument is the value passed when calling.
  • Parameters make subroutines reusable.
  • RETURN sends a value back.
  • A returned value can be stored or used directly.

Worked examples

Example 1

State the difference between a parameter and an argument. [2 marks]

Working

A parameter is the variable named in the subroutine definitiondefine a parameter
An argument is the actual value supplied when the subroutine is calleddefine an argument

Example 2

Explain why parameters make a subroutine more useful. [2 marks]

Working

Different values can be passed in each time the subroutine is calledstate what they allow
so one subroutine works for every case rather than only for fixed valuesexplain the benefit

Example 3

A function called area takes width and height and returns their product. Write the call that stores the area of a 6 by 4 rectangle. [2 marks]

Working

result ← area(6, 4)write the call passing both arguments
The returned value is assigned to result using the assignment arrowexplain what happens to the return value

Common mistakes

  • Using parameter and argument interchangeably.

    Parameter is in the definition; argument is in the call.

  • Passing arguments in the wrong order.

    They match the parameters positionally.

  • Expecting a procedure to return a value.

    Only functions have RETURN.

  • Forgetting to store the returned value.

    Calling a function without using its result discards it.

Exam tips

  • Keep parameter and argument clearly distinct.
  • Match arguments to parameters in order.
  • Use RETURN only in functions.
  • Assign or use the returned value.

Key terms

Parameter
A variable named in a subroutine definition.
Argument
The actual value passed when calling.
Return value
The value a function sends back.
RETURN
The keyword sending a value back from a function.

Related topics

Written and reviewed against the current AQA specification. Spotted an error? Let us know.