Terminology

A data type defines a set of values and a means of representing, manipulating, and interpreting them. Intrinsic numeric and nonnumeric types are defined in the language, and a user can define additional types, known as derived types, which are structures composed of the intrinsic types and of other derived types.

A data object is a constant, a variable, a subobject of a variable, or a subobject of a constant, and has a data type.

A constant has a value that cannot be changed during execution of the program. A constant is a literal constant, unless it has the PARAMETER attribute, in which case it is a named constant.

A variable may have a value and this value can be defined and redefined during execution of the program. It can be a scalar variable, an array variable, or a subobject of a variable.

A subobject of a variable can be an array element, an array section, a character substring, or a structure component. A subobject of a constant is a portion of the constant; the portion referenced may depend on the value of a variable.