<?php
$a = 10;
$b = 20;
echo 'Before Swaping A = '.$a.' and B = '.$b;
$temp = $a + $b;
$a = $temp - $a;
$b = $temp - $b;
echo 'After Swaping A = '.$a.' and B = '.$b;
// swaping without using any third variable
$a = 10;
$b = 20;
echo 'Before Swaping A = '.$a.' and B = '.$b;
$a = ( $a + $b ) - ( $b = $a );
echo 'After Swaping A = '.$a.' and B = '.$b;
?>