求数组中最大数所在的下标，用for来实现。

Question

求数组中最大数所在的下标，数组为 $arr = array(1,5,67,58,40,3,450,6,999,21);用for来实现。

Answer 1

        $index = 0;
        $arr = array(1,5,67,58,40,3,450,6,999,21);
        $max = max($arr);
        foreach( $arr as $k => $num) {
            if($num === $max) {
                $index = $k;
            }
        }
        echo $index;