The Free On-line Dictionary of Computing (30 December 2018):
A loop construct found in many procedural
languages which repeatedly executes some instructions while a
condition is true.
In C, the for loop is written in the form;
for (INITIALISATION; CONDITION; AFTER)
where INITIALISATION is an expression that is evaluated once
before the loop, CONDITION is evaluated before each iteration
and the loop exits if it is false, AFTER is evaluated after
each iteration, and STATEMENT is any statement, including a
compound statement within braces "..", that is executed if
CONDITION is true.
for (i = 0; i < 10; i++)
prints "Hello" 10 times.
Other languages provide a more succinct form of "for"
statement specifically for iterating over arrays or lists.
E.g., the Perl code,
for my $task (@tasks)
calls function "postpone()" repeatedly, setting $task to each
element of the "@tasks" array in turn. This avoids
introducing temporary index variables like "i" in the previous
The for loop is an alternative way of writing a while loop
that is convenient because the loop control logic is collected
in a single place. It is also closely related to the repeat