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The following question has been taken from an Edexcel past paper. It reflects the type of question that may appear in an exam paper.

Discuss the benefits of using subprograms when writing software solutions.

[6 marks]

How to tackle the question

Break the question down into steps:

1. Make a brief list of the benefits of using subprograms
2. Discuss the benefits of subprograms in detail
3. Construct your answer

1. Benefits

In the context of this question, some of the benefits could be:

• no repeated code
• can be reused
• makes programs more readable
• libraries
• can be written in a different language

2. Discuss the benefits

You are asked to discuss the benefits, not describe, state, explain etc.

Discuss means:

• identify the issue that is being assessed within the question
• explore all aspects of the issue
• investigate the issue using reasoning or argument

In the context of this question, some of the benefits might be those identified below:

• Subprograms only have to be written once then debugged once. This saves repeated code and the subprogram can then be reused throughout the program whenever needed.
• Only having to debug the code once in a subprogram is much more efficient than having to debug the same code whenever it appears in the program.
• Using subprograms can help make code easier to read as complex tasks can be moved to a subprogram and given a descriptive name.
• Subprograms can be put into libraries so they can be reused in completely different programs. This is efficient as the programmer doesn’t need to write the code and it won't debugging again.
• Subprograms can be written in a different programming language. This is sometimes beneficial if the different programming language is more suitable for a particular special purpose.

3. Construct your answer

Understanding how essay questions are marked will help you construct your answer in a way that will gain the most marks.

Click here to read the section on how to construct your answer on the previous page.