Algorithm Design and Problem Solving · 4 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 6% of your exam marks.
Decomposition, abstraction and structure charts appear as design-focused questions.
Every program can be described as a pipeline of inputs, processes and outputs. Identifying these clearly is a key step in the analysis stage of the development life cycle.
| Stage | What it is | Examples |
|---|---|---|
| Input | Data that enters the program from outside | Keyboard typing, mouse clicks, sensor readings, file contents, network messages |
| Process | What the program does with the data | Calculate, compare, sort, search, filter, transform |
| Output | Data that leaves the program for the user or the environment | Text on screen, printed page, sound, control signal to an actuator |
Example — Identify the inputs, processes and outputs of a program that calculates the area of a rectangle.
| Stage | What it contains |
|---|---|
| Inputs | Width of the rectangle, height of the rectangle (typed by the user) |
| Processes | Multiply width × height to find the area |
| Outputs | Display the calculated area on the screen |
You may also see a storage category added (data the program keeps for later use, e.g. in memory or in a file). The exam most commonly tests inputs / processes / outputs.
This is sometimes called the IPO (input, process, output) model.