How can I swap two Perl variables without using the third?

Question

I want to swap two variables values without using the third variable in Perl, e. g.:

my $first = 10;
my $second = 20;

Please suggest me how

Answer 1

#!/usr/bin/perl

$a=5;
$b=6;

print "\n The value of a and b before swap is --> $a,$b \n";

$a=$a+$b;
$b=$a-$b;
$a=$a-$b;

print "\n The value of a and b after swap is as follows:";
print "\n The value of a is ---->$a \n";
print "\n The value of b is----->$b \n";