PHP acquisition week

<?php
 function getWeek($time = 0) {
        $week_array=array('日', '一', '二', '三', '四', '五', '六'); //先定义一个数组
        if ($time) {
            return '星期' .$week_array[date('w',$time)];
        } else {
            return '星期' .$week_array[date('w')];
        }
}

echo getWeek();
?>