Inputs and outputs

From Computer Science Wiki
Inputs and Outputs[1]
  • input : what is put in, taken in, or operated on by any process or system
  • output: what is produced, delivered, or supplied (data) by a process or system

In any solution you must clearly understand the specific inputs and outputs.


This is the most basic idea in designing a program: There is input and the input is processed and then there is some sort of output.

This diagram is used from Johnstone, D., Bonner, M., & Tate, M. (2004) "Bringing human information behaviour into information systems research: an application of systems modelling" Information Research, 9(4) paper 191, Available at


Example one[edit]

As an autonomous car is traveling, a radar system scans in front of the vehicle. If an object is detected, the car MIGHT slow down, turn, sound an alarm, honk the horn, or a combination of all four.

The input in this case is the data produced by the radar. The output in this case is the control instructions to the car. Those output instructions might instruct the car to "slow down slowly" or "slow down very quickly".

Example two[edit]

Headlights are the lights in front of a car. Headlights can be either on or off. If a headlight is on, it can be either low or high. A high headlight is bright, and may be distracting for an oncoming car.

A car has a headlight sensor. If the sensor detects headlights AND the headlights are on, AND the headlights are high (or bright), the car will lower the brightness of the headlights.

In this case, the input is the sensor data from the light sensor. The output is the control instructions to lower the lights.

Example three[edit]

You are writing a computer program. Your output is some music. In this case, the input is your instructions (your program) and the output is the signals sent to the speakers to create sound.


These standards are used from the IB Computer Science Subject Guide[2]

  • Identify the inputs and outputs required in a solution.


  2. IB Diploma Programme Computer science guide (first examinations 2014). Cardiff, Wales, United Kingdom: International Baccalaureate Organization. January 2012.