Such definitions of "type" do not give any semantic meaning to types. Syntactic A type is a purely syntactic label associated with a variable when it is declared. Types including behavior align more closely with object-oriented models, whereas a structured programming model would tend to not include code, and are called plain old data structures. ( Parnas, Shore & Weiss 1976) identified five definitions of a "type" that were used-sometimes implicitly-in the literature. Most data types in statistics have comparable types in computer programming, and vice versa, as shown in the following table: The type system uses data type information to check correctness of computer programs that access or manipulate the data. For example, a programmer might create a new data type named " complex number" that would include real and imaginary parts.Ī data type also represents a constraint placed upon the interpretation of data in a type system, describing representation, interpretation and structure of values or objects stored in computer memory. Most programming languages also allow the programmer to define additional data types, usually by combining multiple elements of other types and defining the valid operations of the new data type. A color, on the other hand, might be represented by three bytes denoting the amounts each of red, green, and blue, and a string representing the color's name. Different type systems ensure varying degrees of type safety.Īlmost all programming languages explicitly include the notion of data type, though different languages may use different terminology.įor example, in the Java programming language, the type int represents the set of 32-bit integers ranging in value from −2,147,483,648 to 2,147,483,647, as well as the operations that can be performed on integers, such as addition, subtraction, and multiplication. Data types are used within type systems, which offer various ways of defining, implementing, and using them.