<P> In computer science and computer programming, a data type or simply type is a classification of data which tells the compiler or interpreter how the programmer intends to use the data . Most programming languages support various types of data, for example: real, integer or Boolean . A data type provides a set of values from which an expression (i.e. variable, function ...) may take its values . The type defines the operations that can be done on the data, the meaning of the data, and the way values of that type can be stored . </P> <P> Data types are used within type systems, which offer various ways of defining, implementing and using them . Different type systems ensure varying degrees of type safety . </P> <P> Almost all programming languages explicitly include the notion of data type, though different languages may use different terminology . Common data types include: </P>

Abstract datatypes for real numbers in type theory