### Can you place block A next to block B?

#### Key Definition – Pseudocode

## Pseudo-code is …

**…non-standardised**

Pseudocode can look similar to code but it does not need to follow the rules of a particular language.

**…used to develop algorithms before coding**

This means you can develop algorithms quickly without worrying whether your script will work with a particular programming language.

**…easily converted in to a number of different languages.**

## Rules – What Rules?!?

There are no set rules for writing pseudocode, but you will often see the following:

**INPUT**– indicates a user will be inputting something**OUTPUT**– indicates that an output will appear on the screen**WHILE**– a loop (iteration that has a condition at the beginning)**FOR**– a counting loop (iteration)**REPEAT – UNTIL**– a loop (iteration) that has a condition at the end**IF – THEN – ELSE**– a decision (selection) in which a choice is made- any instructions that occur inside a selection or iteration are usually indented

### Challenge 1 – Double the number

Write a pseudo-code algorithm that asks the user for a number, doubles and then displays the number.

### Challenge 2 – Calculate the area of a circle

Write a pseudo-code algorithm that asks the user for the radius of a circle and then displays the area of the circle.

### Challenge 3 – Calculate the circumference of a rectangle.

Write a pseudo-code algorithm that asks the user for the length and width of a rectangle and then displays the circumference of the rectangle.