An informal definition (a formal definition is not considered here , although it exists): finite set of rules that give a sequence of operations to solve all the problems of a given type. Of simpler form, we can say that an algorithm is a set of steps that allows us to collect a data. In addition it must fulfill these conditions:· Finitud: the algorithm must finish after a finite number of steps. It is more, is almost fundamental that it is in a reasonable number of steps. · Definibilidad: the algorithm must be defined of precise form for each step, that is to say, each step is necessary to avoid all ambiguity when defining. Since the human language is vague, the algorithms are expressed by means of a formal, or mathematical language or of programming for a computer. · Entrance: the algorithm will have zero or more entered, that is to say, amounts given before beginning the algorithm. These amounts belong in addition to specified sets to objects. By example, they can be chains of characters, whole numbers, natural, fractional, etc. One is always expressed representative amounts of the real world of such form that are apt for their interpretation by the computer. · Exit: the algorithm has one or more exits, in relation to the entrances. · Effectiveness: it is understood by that a person is able to make the algorithm of exact way and without aid of a machine in a finite time interval .