凯撒日期（求某一天是这一年的第几天）

[PHP]代码

/***********************************************************
变 量 名：$year ,$month ,$day为前台提交的值

作    者：shyhero

E - mail：[e-mail]
************************************************************/

<?php
	$year =$_POST ['year'];
	$month =$_POST ['month'];
	$day =$_POST ['day'];
	
	$sum =0 ;
	if(month>12)
		return;
	switch($month-1)
	{
		case 12:$sum +=31;
		case 11:$sum +=30;
		case 10:$sum +=31;
		case 9:$sum +=30;
		case 8:$sum +=31;
		case 7:$sum +=31;
		case 6:$sum +=30;
		case 5:$sum +=31;
		case 4:$sum +=30;
		case 3:$sum +=31;
		case 2:
			if( ! ( $year % 4 ) && ( $year % 100 ) || ! ($year % 400))
				$sum +=29;
			else
				$sum +=28;
		case 1:$sum +=31;break;
		default: return;
	}
	
	echo $sum+$day;
?>