编辑一个C语言程序：输入任意年月日，判断该天是这一年的第几天。

已经修改过了：
#include "stdio.h"
main()
{
int day,month,year,sum,leap;
printf("please input year,month,day(like 2000 10 01):");
scanf("%d%d%d",&year,&month,&day);
if(
(month>12||day>31)||/*the day (month>12 or day>31) is not exist!*/
((month==4||month==6||month==9||month==11)&&day==31)||/*the day [day=31 in (4,6,9,11)st month] is not exist!*/
(month==2&&(year%4==0&&year%100!=0)||(year%100==0&&year%400==0)&&day>29)||/*the day (day>29) in February is not exist!*/
(month==2&&day>28))/*the day(yera%4!=0) is not exist!*/
printf("the day is not exist!");
else
{
switch(month) /*先计算某月以前月份的总天数*/
{
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;