/*求某年/月/日是星期几*/
#include<stdio.h>
//星期函数声明
int weekday(int year,int month,int day);
void main()
{
int year,month,day,flag;
int days[12]={31,28,31,30,31,30,31,31,30,31,30,31};
printf("请输入年份：\n");
scanf("%d",&year);
printf("请输入月份：\n");
scanf("%d",&month);
printf("请输入日号：\n");
scanf("%d",&day);
days[1] = (year%4==0 && year0!=0 || year@0==0) ? 29:28;//闰年调整
if(year>0 && month>0 && month<13 && day>0 && day<=days[month-1])//判断输入是否正确
{
flag=weekday(year,month,day);
switch(flag)
{
case 0:
printf("%d年%d月%d日是星期日\n",year,month,day);
break;
case 1:
printf("%d年%d月%d日是星期一\n",year,month,day);
break;
case 2:
printf("%d年%d月%d日是星期二\n",year,month,day);
break;
case 3:
printf("%d年%d月%d日是星期三\n",year,month,day);
break;
case 4:
printf("%d年%d月%d日是星期四\n",year,month,day);
break;
case 5:
printf("%d年%d月%d日是星期五\n",year,month,day);
break;
case 6:
printf("%d年%d月%d日是星期六\n",year,month,day);
break;
default:
printf("输入错误，请重新输入！\n",year,month,day);
}
}else
{
printf("输入错误，请重新输入！\n");
}
}
int weekday(int year,int month,int day)
{
int Weekday=(day+2*month+3*(month+1)/5+year+year/4-year/100+year/400)%7;
return Weekday;
}
运行结果：
