Finite State Machines

Finite State Machine- Any device that stores its current status and whose status can be changed as a result of an input

• Used in many areas of computer science
• Allow programmers to think about all of the different states or conditions a device/code could be in and to plan what should happen to that device when it recieves an allowable input of some kind
• They are particularly useful at the design stage as they force the designer to think about every possible input and how the changes the state of the machine

(input/output) e.g. (0/1) shows 0 is input and 1 is output

Symbol                                   Meaning

[Circle]                                    State

[Circle with arrow pointing     Starting State

at it]

[Circle within Circle]               Accept (or end) State

['i' with an arrow going           Connector (with i being the input)

over it]

['j/k' with an arrow going        Connector (with j being input and k being output]

over it]

The same information can be represented as a decision table. This makes it easier to observe all possible conditions are accounted for.