#include<stdio.h>
void main()
{
int year,month,day,sum,i,xingqi;
printf("请输入年 月 日:");
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;
}
sum=sum+day+(year-1)*365;
for(i=1;i<=year;i++)
if(i%400==0||(year%4==0&&year%100!=0))
sum=sum+1;
if(sum%7==0)
printf("这一天是星期天\n",xingqi);
else printf("这一天是星期%d\n",sum%7);
}
不知道哪里错了