Algorithms
Computer Science: KS3, topic 1.2.1
Algorithms
An algorithm is the steps and rules that are followed when completing a process. The main actions in an algorithm are sequence, selection and repetition.
Sequence
- The sequence of an algorithm is the order of the steps that make up the algorithm.
- E.g. the toppings cannot be put on the cakes until they are cooked.
Selection
- Selection is a yes or no choice.
- A yes or no choice can be thought of as an ‘if ... then ’ instruction.
- E.g. should the cakes be taken out of the oven?
- If an inserted knife comes out clean, then yes.
- If an inserted knife comes out dirty, then no.
Repetition
- Repetition means doing the same step over again.
- The step can be repeated with different variables (something that can change).
- The toppings must be placed on the cakes.
- The step is repeated for each cake (repetition) but the type of topping can change each time (variable).
Repeat until...
- Sometimes a step can be repeated until something happens.
- Then we can move to the next step.
- A step is repeated until something happens can be thought of as a ‘repeat until…’ instruction
- Put cake batter in each paper case.
- Repeat until all the cases are filled
- Then stop and go to the next step.
Test yourself on Algorithms
Which main action in an algorithm can be represented by an "if ... then' instruction?