Algorithms and Flowcharts : Flowcharts

A flowchart consists of a sequence of instructions linked together by arrows to show the order in which the instructions must be carried out. Each instruction is put into a box. The boxes are different shapes depending upon what the instruction is. The main four types of box are :

Flowcharts are often used to describe in detail algorithms that will be carried out by a computer. When a computer carries out an algorithm the computer is said to execute the algorithm. Execution is also sometimes referred to as running.

Here are some example situations in which flowcharts are often used :

Control Systems	The operation of a control system can be described using a flowhcart.
Macros	The actions that a macro should execute can be planned using a flowchart.
Computer Programs	Computer programs can be designed by drawing flowcharts to show what instructions the program should execute.

Sometimes a more general view of how an information system will operate is required. A flowchart for a complete information system would cover many pages of paper and would be very difficult to produce and understand. A more general description of how an information system operates can be given by using a system flowchart.

GCSE ICT Companion 04 - (C) P Meakin 2004