Computer Dictionary of Information Technology

while loop

The loop construct, found in nearly all procedural languages, that executes one or more instructions (the "loop body") repeatedly so long as some condition evaluates to true. In contrast to a repeat loop, the loop body will not be executed at all if the condition is false on entry to the while.

For example, in C, a while loop is written

	while () ;

where <expr> is any expression and <statement> is any statement, including a compound statement within braces "..".

A for loop, e.g. in the C language, extends the while loop syntax to collect pre-loop initialisation and loop-end logic into the beginning of the statement.

Perl provides the "until" loop that loops until the loop condition is true.