C语言的一道题 知道1900年1月1日是星期一，设计一个程序，输入年月日，输出星期几

#include "stdio.h"

int main(void)

{

int a,b,year,month,day,count=0;

int mon[12]={0,31,28,31,30,31,30,31,31,30,31,30};

printf("Please input year month day like this xxxx,xx,xx\n");

scanf("%d,%d,%d",&year,&month,&day);

for(a=1900;a

if(a%100!=0&&a%4==0||a%400==0)

count+=2;

else

count+=1;

for(a=1;a

{count+=mon[a];

if(a==2&&year%100!=0&&year%4==0||year%400==0)

count++;

}

count+=day;

b=count%7;

switch(b)

{

case 1:

printf("The day is Monday\n");

break;

case 2:

printf("The day is Tuesday\n");

break;

case 3:

printf("The day is Wednesday\n");

break;

case 4:

printf("The day is Thursday\n");

break;

case 5:

printf("The day is Friday\n");

break;

case 6:

printf("The day is Satday\n");

break;

case 0:

printf("The day is Sunday\n");

break;

}

}