coin changer

<?php
/**
 * coin changer
 *
 * usage:
 * $coin = 179;
 * $ary = array(10,50,5,100);
 * $result = coin_changer($coin, $ary);
 * @param int $raw_coin
 * @param array $coin_amount_ary
 * @return array
 */
function coin_changer($raw_coin = 0, $coin_amount_ary = array()) {
  $coin_ary = array_keys($coin_amount_ary);
  $result_ary = array();
  rsort($coin_ary);
  $i = 0;
  foreach ($coin_ary as $coin) {
    if ($raw_coin <= 0) {
      break;
    }
    $cnt = intval($raw_coin / intval($coin)); //張數
    $raw_coin %= intval($coin); //餘額
    $result_ary[$coin] = $cnt;
  }
  return $result_ary;
}

$coin = 179;
$ary = array(10,50,5,100);
$result = coin_changer($coin, $ary);
print_r($result);