Page "Algorithm" Paragraph 2

More precisely, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function.

Starting from an initial state and initial input ( perhaps empty ), the instructions describe a computation that, when executed, will proceed through a finite number of well-defined successive states, eventually producing " output " and terminating at a final ending state.

The transition from one state to the next is not necessarily deterministic ; some algorithms, known as randomized algorithms, incorporate random input.