For Loop

In computer science a for loop is a programming language statement which allows code to be repeatedly executed. A for loop is classified as an iteration statement.

Unlike many other kinds of loops, such as the while loop, the for loop is often distinguished by an explicit loop counter or loop variable. This allows the body of the for loop (the code that is being repeatedly executed) to know about the sequencing of each iteration. For loops are also typically used when the number of iterations is known before entering the loop. For loops are the shorthand way to make loops when the number of iterations is known, as a for loop can be written as a while loop.

The name for loop comes from the English word for, which is used as the keyword in most programming languages to introduce a for loop. The loop body is executed "for" the given values of the loop variable, though this is more explicit in the ALGOL version of the statement, in which a list of possible values and/or increments can be specified.

In FORTRAN and PL/I though, the keyword DO is used and it is called a do loop, but it is otherwise identical to the for loop described here and is not to be confused with the do while loop.