Representing Algorithms
Represent algorithms using flow charts
Input-Process-Output
All programs can be broken down into combinations of:
- Inputs
- Processes
- Outputs
Flowcharts
- An algorithm can be represented by a flowchart.
- This is a graphical representation that:
- uses symbols to show each step,
- with arrows showing how to move between each step.
Flowcharts
| Line | An arrow represents control passing between the connected shapes | |
| Process | This shape represents something being performed or done | |
| Sub-routine | This shape represents a subroutine call that will relate to a separate, non-linked flowchart | |
| Input/output | This shape represents the input or output of something into or out of the flowchart | |
| Decision | This shape represents a decision (Yes/No or True/False) that results in two lines representing the different possible outcomes | |
| Terminal | This shape represents the 'Start' and 'End' of the process |
Flowcharts
- All flow charts begin and end with the terminal shape, indicating the start and end of the flow chart.
Flowcharts
- Inputs and outputs are represented by a parallelogram
Flowcharts
- Decision boxes must have two possible outputs:
- True/False
- Yes/No
Flowcharts
- All other processes are represented by a rectangle
Flowcharts
- Where algorithms are decomposed into separate sub-routines, a rectangle with two extra vertical lines is used.
Flowcharts
Representing Algorithms Represent algorithms using flow charts