AQA · GCSE · Computer Science
Course version: 8525 · Version from Sept 2020
Be aware that a computer program is an implementation of an algorithm and…
Full specification wording
Representing algorithms: Be aware that a computer program is an implementation of an algorithm and that an algorithm is not a computer program.
An algorithm is the sequence of steps that completes a task; a computer program is one implementation of that algorithm written in a programming language that a computer can run.
Checked against the AQA 8525 specification (opens in a new tab) on .
- Point 2 of 8
Study notes
From the checked teaching notes for this specification point.
The idea
An algorithm is the sequence of steps that completes a task; a computer program is one implementation of that algorithm written in a programming language that a computer can run. The algorithm is the plan; the program is the coded version of the plan. For example, an algorithm for adding two numbers describes the steps: take the first number, take the second number, add them, store the result. A program such as one written in Python carries out those steps using variables and an addition statement. The same algorithm could be implemented in several different programming languages, giving several different programs. Crucially, an algorithm is not a computer program: an algorithm can exist without any code, for example as pseudocode or a flowchart, whereas a program is a concrete implementation that a computer executes.
What earns the marks
- States that a computer program is an implementation of an algorithm.
- States that an algorithm is not a computer program.
- Explains that the algorithm is the sequence of steps or plan, while the program is the coded version that a computer runs.
- Recognises that one algorithm can be implemented as programs in different programming languages.
- Recognises that an algorithm can be represented without code, for example as pseudocode or a flowchart.
Common mistakes and how to put them right
Treating 'algorithm' and 'program' as interchangeable.
Put it right: The algorithm is the sequence of steps and the program is its implementation in code.
Thinking an algorithm must be executable by a computer.
Put it right: An algorithm can be written as pseudocode or a flowchart and still be an algorithm.
Assuming one algorithm gives only one program.
Put it right: The same algorithm can be implemented in several programming languages.
Exam tips
- Use the phrase 'a program is an implementation of an algorithm' when explaining the relationship.
- When comparing options, check which one keeps the algorithm as the plan and the program as the coded version.
- Give a short example, such as an algorithm for adding two numbers implemented in a programming language, to justify your choice.
Try the lesson
The start of the Representing algorithms: Be aware that a computer program is an implementation of an algorithm and that an algorithm is not a computer program. lesson, made from checked teaching notes for this specification point.
Have a go first
A student writes a set of instructions for finding the largest number in a list. They then write the same instructions in Python so that a computer can carry them out. Which statement is correct?
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