#include<stdio.h>
int main()
{
int year,month,day,sum,leap;
printf(“请输入年月日\n”);
scanf("%d%d%d",&year,&month,&day);
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(“数据错误\n");break;
}
sum=sum+day;
if((year%4==0&&year%100!=0)||year%400==0)
{
leap=1;
}
else
{
leap=0;
}
if(leap=1&&month>2)
{
sum++;
}
printf("这是这一年的第%d天\n",sum);
if(month>12&&month<1)
{
printf("数据错误\n");
}
return 0;
}