Flow Charts
Components and Conventions of a Flow Chart
A flow chart is a diagram that breaks a process into steps and decisions. Every shape comes from a standard set of symbols, so a flow chart drawn by one person can be read the same way by anyone else, whatever they know about the process.
| Symbol | Shape | What it shows |
|---|---|---|
| Terminator | Rounded rectangle or oval | The start or the end of the flow chart |
| Process | Rectangle | A step where something is done |
| Decision | Diamond | A question or comparison with more than one possible route |
| Input/output | Parallelogram | Data entering the process or leaving it |
| Arrow | Line with an arrowhead | The direction the flow travels in |
Decisions and arrows
A decision box holds a question or comparison, and two arrows leave it, one labelled Yes and one labelled No. The labels matter because the shape alone does not say which route is taken when the answer is true and which when it is false. Each arrow then leads to a different part of the flow chart, so the reader can see both outcomes.
A flow in action
Imagine a school canteen till. The flow chart opens with a start terminator, then an input parallelogram reading “Enter money”. What the user types is stored in a variable so it can be used later. The next shape is a decision diamond asking money >= 2.50? — the comparison belongs in the diamond, not in the input box. The Yes arrow leads to a process rectangle, “Serve hot meal”, while the No arrow leads to an output parallelogram, “Display ‘not enough money’”. Both routes finish at an end terminator, so the process has one clear beginning and one clear finish.
Practise this
OCR Creative iMedia · Flowcharts