[C]计算某一天是该年中的第几天

输入年月份，计算今天是今年的第几天？

#include<stdio.h>
void main()
{
int year,month,day,days,i,d;
printf("请输入年，月，日：\n");
scanf("%d,%d,%d",&year,&month,&day);
days=0;
for(i=1;i<month;i++)
{
switch(i)
{
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:d=31;break;
case 4:
case 6:
case 9:
case 11:d=30;break;
case 2:if(year%4==0&&year%100!=0||year%400==0)
d=29;
else d=28;
}
days+=d;
}
printf("%d年%d月%d日是这一年的第%d天。\n",year,month,day,days+day);
}


运行结果：