5.19. Perl while cycle

while statement when a given condition is true the statement or group of statements is executed repeatedly. The condition is tested before the loop body executes.

5.19.1. Grammar #

The syntax format is as follows:

while(condition)
{
   statement(s);
}

Here, statement(s) can be a single statement or a block of code madeup of several statements.

condition can be any expression when the condition is true loopis executed when the. When the condition is false program flow exits the loop

5.19.2. Flow chart #

In the chart while key point of a loop is that the loop may not be executed at all. When the condition is false skips the loop body and directly executes the following while the next statement of the loop.

Example #

#!/usr/bin/perl$a=10;# execute while circulate
while($a<20){printf"a's value is
:$a\\n";$a=$a+1;}

Variables in the program $a execute the loop body less than 20:00, in the variable $a greater than or equal to 20:00, exit the loop.

Execute the above program, and the output is as follows:

The value of a is: 10
The value of a is: 11
The value of a is: 12
The value of a is: 13
The value of a is: 14
The value of a is: 15
The value of a is: 16
The value of a is: 17
The value of a is: 18
The value of a is: 19