Writing & Amending Algorithms (Cambridge (CIE) IGCSE Computer Science)

Revision Note

Robert Hampton

Written by: Robert Hampton

Reviewed by: James Woodhouse

Algorithmic Thinking

What is algorithmic thinking?

  • Algorithmic thinking is the process of creating step-by-step instructions in order to produce a solution to a problem

  • Algorithmic thinking requires the use of abstraction and decomposition to identify each individual step

  • Once each step has been identified, a precise set of rules (algorithm) can be created and the problem will be solved

  • An example of algorithmic thinking is following a recipe, if the recipe is followed precisely it should lead to the desired outcome

  • A set of traffic lights is an example of how algorithmic thinking can lead to solutions being automated

Examiner Tips and Tricks

Writing algorithms in an exam can be challenging and time consuming. It's important to allocate your time carefully to not spend too little or too long writing an algorithm

You will likely make mistakes and rewrite your algorithm a few times. Use scrap paper or the back of your exam paper if possible to sketch out your ideas before committing to your answer. This will make your answer clearer, neater and easier to read, follow and understand

You may wish to chunk your algorithm into parts initially, for example, “This part will enter the grades”, “this part will calculate the total”, and “This part will allocate grades”. You can then put the whole algorithm together in order later

Make a plan before you start answering the question and writing your algorithm. A plan can be simple but allows you to order your thoughts, for example:

Part 1: Declare and initialise variables

Part 2: Allocate marks for each subject

Part 3: Allocate grades for each student's subject

Part 4: Include a loop

Part 5: Output all necessary data

Pseudocode does not have a syntax, therefore you can write an algorithm in any way which is easily understandable. Caution is advised to stick to IGCSE specification standards to ensure your answer is consistent and easy for examiners to follow

Be sure to use variable names and data provided in the question as given. Failure to do so will lose you marks

Remember to comment on your code. It helps both you and the examiner understand your answer and also awards marks in the mark scheme!

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Robert Hampton

Author: Robert Hampton

Expertise: Computer Science Content Creator

Rob has over 16 years' experience teaching Computer Science and ICT at KS3 & GCSE levels. Rob has demonstrated strong leadership as Head of Department since 2012 and previously supported teacher development as a Specialist Leader of Education, empowering departments to excel in Computer Science. Beyond his tech expertise, Robert embraces the virtual world as an avid gamer, conquering digital battlefields when he's not coding.

James Woodhouse

Author: James Woodhouse

Expertise: Computer Science

James graduated from the University of Sunderland with a degree in ICT and Computing education. He has over 14 years of experience both teaching and leading in Computer Science, specialising in teaching GCSE and A-level. James has held various leadership roles, including Head of Computer Science and coordinator positions for Key Stage 3 and Key Stage 4. James has a keen interest in networking security and technologies aimed at preventing security breaches.