Find Palindrom from string

printPalindromes.php

<?php
function printPalindromes($str)
{
    #$str = strtolower(preg_replace("'\s+'", '', $str));
    $str = strtolower(preg_replace("([^A-Za-z0-9])", "", $str));
    $length = strlen($str);
    $reverse = strrev($str);
    $matches = array();
    $palindrom = $str;

    // Check for character matching from reverse position
    for ($i = 0; $i < ($length / 2); $i++) {
        if ($str[$i] == $str[($length - $i - 1)]) {
            $matches[] = $str[$i];
        }
    }

    // Check for word matching
    for ($i = 0; $i < ($length / 2); $i++) {
        if( $str == $reverse){
            $matches[] = $str;
            $str = substr($str, 1, -1);
            $reverse = substr($reverse, 1, -1);
        }
    }

    $matches = array_unique($matches);
    $found = count($matches);

    if ($found == 0) {
        echo 'No Palindrom found';
    } else {
        echo 'The Word "'.$palindrom.'" contains '.$found.' palindromes:' . '<br>';
        foreach ($matches as $key => $match) {
            echo $match . '<br>';
        }
    }
}
printPalindromes('madam');