In
computer programming
Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as anal ...
, a control variable is a
program variable
In computer programming, a variable is an abstract storage location paired with an associated symbolic name, which contains some known or unknown quantity of information referred to as a ''value''; or in simpler terms, a variable is a named cont ...
that is used to regulate the
flow of control of the program.
In definite iteration, control variables are variables which are successively assigned (or bound to) values from a predetermined sequence.
Special rules
In some programming languages, control variables are just ordinary variables used for manipulating the program flow. This is the case of
C,
Fortran, and
Pascal, which allow for control variables to have their values changed within the loop body.
However, some languages have special rules for control variables. In
Ada, for instance, the control variable of a
for-loop must remain constant within the loop body.
References
Mathematical terminology
Computing terminology
{{comp-sci-stub