We have to use the bellow mentioned syntax to swap two number using PHP, with or without using the third variable.

BY Best Interview Question ON 01 Oct 2019

Example

Without using third variable

<?php echo "Before Swapping:";
$a = 1;
$b = 2;
echo "a = $a<br>";
echo "b = $b<br>";

echo "After swapping:<br>";

$a = $a + $b;
$b = $a - $b;
$a = $a - $b;
echo "a = $a<br>";
echo "b = $b";
?>

With using third variable

<?php echo "Before Swapping:<br>";
$a = 1;
$b = 2;
echo "a = $a<br>";
echo "b = $b<br>";

echo "After swapping:<br>";
$temp = $a;
$a = $b;
$b = $temp;

echo "a = $a<br>";
echo "b = $b<br>";
?>