Print string in reverse order in php

Some time ago during a job interview I got the task to print a string in reverse order in PHP. Here i am writing program for print string in revers order using strrev() function.

<?php
$str = 'This is string Print In Revers Order';
echo strrev(str);
?>

Print string in revers order without using strrev() function.

<?php 
$s = 'This is string Print In Revers Order';
for ($i = 0, $length = strlen($s); $i < $length; $i++) {
 echo $s{$length - $i - 1};
}
?>

Example 2: Print string in revers order without using strrev() function.

<?php 
$str = 'This is string Print In Revers Order';
for($i=strlen($str)-1, $j=0; $j<$i; $i--, $j++)
{
 list($str[$j], $str[$i]) = array($str[$i], $str[$j]);
}
echo $str;
?>