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There are two ways of representing algorithms:

• pseudocode
• a flowchart

Representing iteration in pseudocode

Writing in pseudocode is rather like writing in a programming language. Each step of the algorithm is written on a line of its own, in sequence.

Consider this simple six-step algorithm for cleaning your teeth:

1. set number_of_teeth_cleaned to 0
2. put toothpaste on toothbrush
3. use toothbrush to clean a tooth
4. increase number_of_teeth_cleaned by 1
5. if number_of_teeth_cleaned < 32 then go back to step 3
6. rinse toothbrush

With each iteration, a decision needs to be made as to whether to continue iterating or not. Decisions are represented as selection.

In pseudocode, the algorithm would look like this:

number_of_teeth_cleaned = 0
put toothpaste on toothbrush
REPEAT
	procedure clean_tooth
	number_of_teeth_cleaned = number_of_teeth_cleaned + 1
UNTIL number_of_teeth_cleaned = 32
rinse toothbrush

Representing iteration in a flowchart

A flowchart uses a diagram to explain the steps of an algorithm.

In a flowchart, the algorithm would look like this: