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 for variable
From The Free On-line Dictionary of Computing (30 December 2018) :

      (Sometimes "var" /veir/ or /var/) A named memory
     location in which a program can store intermediate results and
     from which it can read it them.  Each programming language
     has different rules about how variables can be named, typed,
     and used.  Typically, a value is "assigned" to a variable in
     an assignment statement.  The value is obtained by
     evaluating an expression and then stored in the variable.  For
     example, the assignment
     	x = y + 1
     means "add one to y and store the result in x".  This may look
     like a mathematical equation but the mathematical equality is
     only true in the program until the value of x or y changes.
     Furthermore, statements like
     	x = x + 1
     are common.  This means "add one to x", which only makes sense
     as a state changing operation, not as a mathematical equality.
     The simplest form of variable corresponds to a single-{word
     of memory or a CPU register and an assignment to a
     load or store machine code operation.
     A variable is usually defined to have a type, which never
     changes, and which defines the set of values the variable can
     hold.  A type may specify a single ("atomic") value or a
     collection ("aggregate") of values of the same or different
     types.  A common aggregate type is the array - a set of
     values, one of which can be selected by supplying a numerical
     Languages may be untyped, weakly typed, strongly typed,
     or some combination.  Object-oriented programming languages
     extend this to object types or classes.
     A variable's scope is the region of the program source
     within which it represents a certain thing.  Scoping rules are
     also highly language dependent but most serious languages
     support both local variables and global variables.
     Subroutine and function formal arguments are special
     variables which are set automatically by the language runtime
     on entry to the subroutine.
     In a functional programming language, a variable's value
     never changes and change of state is handled as recursion over
     lists of values.

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