Algorithms and Flow Charts

Today's Lesson

Learning goal:
- Understand how algorithms are shown as a flowchart 
Success criteria:
- Display an algorithm using flowchart symbols

What is a flow chart?

A flow chart is a way to visually display an algorithm

Format of a flow chart

A flow chart uses specific shapes to organise an algorithm.

Let's find out about them now.

Key symbols

Terminator

Step or process

Decision

So what do these terms and shapes mean?

Terminator Blocks

• Represented by a straight-sided oval

• MUST be the first and last line in your algorithm

• Should only contain the words "Begin" or "End"

• Should not contain any actions

​Step or Process Blocks

• Represented by a rectangle

• Used for actions or steps

• Give clear, simple actions

• Can only give a single action to complete in each step

• Involves no decision-making
  

Decision Blocks

• Represented by a diamond

• Used for decisions

• Worded in such a way that "yes" and "no" are the only possible answers

• Need to clearly label which path to take for "yes" and which one for "no"

The flow in must enter via the top, but the flow out can use any 2 of the remaining 3 points

• Must flow downwards

• All paths must lead to the END terminator
  

Flow Charts

​Complete the flow chart activities in the word document in your OneNote

Practise Time