Looping Statements

Perl has a while statement that’s very similar to C’s. The basic syntax is

while (condition) {
    # Body of the loop which is executed when "condition" is true 
}

The last statement exits a loop, much like a C break statement. For example, Listing 2.8 computes the square of the first 10 integers.

Listing 2.8. square.pl

use strict; 
use warnings; 

my $number = 1;    # The number we are looking at 
my $square;        # The square of the number 

while (1) {
    $square = $number ** 2; 
    print "$number squared is $square
"; 
    ++$number; 
    if ($number > 10) {
        last; 
    } 
}

To start a loop over, use the next statement. This is the equivalent of the C statement continue.

The for Statement

The for statement in Perl works much like the C version. It has three parts: an initialization statement, a limit expression, and an increment statement. Listing 2.9 shows an example.

Listing 2.9. square.pl

use strict; 
use warnings; 

my $number; 
my $square; 

for ($number = 0; $number <= 10; $number++) {
    $square = $number ** 2; 
    print "$number squared is $square
"; 
}