<Tr> <Td> Control flow </Td> </Tr> <P> In computer science, a for - loop (or simply for loop) is a control flow statement for specifying iteration, which allows code to be executed repeatedly . Various keywords are used to specify this statement: descendants of ALGOL use "for", while descendants of Fortran use "do ." There are other possibilities, for example COBOL which uses "PERFORM VARYING". </P> <P> A for - loop has two parts: a header specifying the iteration, and a body which is executed once per iteration . The header often declares an explicit loop counter or loop variable, which allows the body to know which iteration is being executed . For - loops are typically used when the number of iterations is known before entering the loop . For - loops can be thought of as shorthands for while - loops which increment and test a loop variable . </P> <P> The name for - loop comes from the English word for, which is used as the keyword in many programming languages to introduce a for - loop . The term in English dates to ALGOL 58 and was popularized in the influential later ALGOL 60; it is the direct translation of the earlier German für, used in Superplan (1949--1951) by Heinz Rutishauser, who also was involved in defining ALGOL 58 and ALGOL 60 . 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 . </P>

A variable that determines whether or not a loop will continue is a