Designing, creating and refining algorithms - OCRAlgorithm production

An algorithm is a logical, step-by-step process for solving a problem. Algorithm production is part of algorithmic thinking, an important concept in computational thinking. This focuses on how a desired solution can be reached by identifying the steps needed to get there. You can read more about this in the computational thinking guide.

Algorithms are normally written as one of the following:

• pseudocode
• a flow diagram

An algorithm should be seen as a starting point before writing a program. The finished program should follow the steps the algorithm describes.

Before an algorithm can be designed, it is important to check that the problem is completely decomposed. The decomposed problem should consider:

• What are the inputs into the problem?
• What will be the outputs of the problem?
• In what order do instructions need to be carried out?
• What decisions need to be made in the problem?
• Are any areas of the problem repeated?

Only when a problem is properly decomposed and understood can an algorithm design begin.

Structure diagrams

Structure diagrams are a visual way of breaking down a problem into smaller parts. They show how a problem is organised by dividing it into components and are frequently used when designing systems. Each box on the diagram represents a separate part with lines showing how each one connects or depends upon the other. For example, a school website structure diagram may include:

• Home page
• Student zone
• Teacher zone
• Parental zone
• Contact page
• About us

Each section will then have sub-sections, such as timetable, newsletters, term dates, etc.