冒泡排序

<?php
function maoPao(array $arr)
{
    $len = count($arr);
    for ($k = 0; $k <= $len; $k++) {
        for ($j = $len - 1; $j > $k; $j--) {
            if ($arr[$j] < $arr[$j - 1]) {
                $temp = $arr[$j];
                $arr[$j] = $arr[$j - 1];
                $arr[$j - 1] = $temp;
            }
        }
    }
    return $arr;
}

$arr = [8, 2, 34, 5];
$str = '1,6,4,5';
//print_r(explode(',',$str));
print_r(maoPao(explode(',', $str)));

//var_dump(str_split($str));