check if string ends with specific sub-string in php

<?php
// check if  string ends with specific sub-string
function endsWith($currentString, $target)
{
    $length = strlen($target);
    if ($length == 0) {
        return true;
    }

    return (substr($currentString, -$length) === $target);
}
  
    $mystr="Test String";
    if(endsWith($mystr,"ing"))
	   echo "String ends with 'ing'";
	else 
	   echo "String doesn't end with 'ing'";
	   
?>