php实现纯汉字字符串倒置

<?php/** * 字符串倒置 * @param unknown $str */header("Content-Type:text/html;charset=utf8");function mystring($str){$arr=array();$len = mb_strlen($str,"UTF-8");for($i=0;$i<$len;$i++){$arr[]=mb_substr($str,$i,1,"UTF-8");}$arr=array_reverse($arr);return implode("", $arr);}echo mystring("字符串倒置");