From: http://www.phpchina.com/bbs/viewthread.php?tid=33757
算法一
- function xxxx($str) {
- $return = '';
- for ($i = 0; ; $i++) {
- @$s = $str{$i};
- if ($s) {
- $return = $s . $return;
- } else {
- break;
- }
- }
- return $return;
- }
算法二
- $str = 'ABCDEF';
- $i = 0;
- while ($str[$i++]);
- $out = '';
- $i-=2;
- while ($str[$i]) {
- $out .= $str[$i--];
- }
- echo $out;
