大神們啊，我這是怎么回事??？
#include?<stdio.h>
int?main()
{
	int?year?=?2008;
	int?month?=?8;
	int?day?=?8;
	printf("the?day?is?number?:\t");
	int?flag,?sum;
	switch?(month)
	{
	case?'1':sum?=?0;?break;
	case?'2':sum?=?31;?break;
	case?'3':sum?=?59;?break;
	case?'4':sum?=?90;?break;
	case?'5':sum?=?120;?break;
	case?'6':sum?=?151;?break;
	case?'7':sum?=?181;?break;
	case?'8':sum?=?212;?break;
	case?'9':sum?=?243;?break;
	case?'10':sum?=?273;?break;
	case?'11':sum?=?304;?break;
	case?'12':sum?=?334;?break;
	default:printf("error!\n");?break;
	}
	if?(year?%?400?==?0?||?year?%?4?==?0?&&?year?%?100?!=?0)
		flag?=?1;
	else
		flag?=?0;
	if?(month>2)?
		sum?=?sum?+?flag?+?day;
	else?sum?=?sum?+?day;
	printf("%d年%d月%d日是該年第%d天\n",?year,month,day,sum);
	return?0;
}