Iteration In Algorithms - KS3 Computer Science Revision - BBC

In this guide

1. Revise
2. Test

Pages

1. Iteration in algorithms
2. Iteration in practice: Cleaning teeth
3. Conditions and counters
4. Representing iteration

Iteration in algorithms

An algorithm is a plan, a set of step-by-step instructions to solve a problem. There are three basic building blocks (constructs) to use when designing algorithms:

• sequencing
• selection
• iteration

These building blocks help to describe solutions in a form ready for programming.

What is iteration?

Open Transcript

Iteration in programming means repeating steps, or instructions, over and over again. This is often called a ‘loop’.

Algorithms consist of instructions that are carried out (performed) one after another. Sometimes an algorithm needs to repeat certain steps until told to stop or until a particular condition has been met.

Key factIteration is the process of repeating steps.

For example, a very simple algorithm for eating breakfast cereal might consist of these steps:

• put cereal in bowl
• add milk to cereal
• spoon cereal and milk into mouth
• repeat step 3 until all cereal and milk is eaten
• rinse bowl and spoon

Why is iteration important?

Iteration allows algorithms to be simplified by stating that certain steps will repeat until told otherwise. This makes designing algorithms quicker and simpler because they don’t need to include lots of unnecessary steps.

Next pageIteration in practice: Cleaning teeth

More guides on this topic

• Designing an algorithm
• Searching
• Sorting
• Sequencing
• Selection
• Logical reasoning

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