已知2009年1月1号是星期四，给定2009年的任何一天（月日），求这天是星期几（输出最后结果要求用switch语句实现）。一周七天用以下标识：
Monday，Tuesday，Wednesday，Thursday，Friday，Saturday，Sunday
例如：输入 3.30 时应输出 Monday，输入 6.19 时应输出 Friday
#include<stdio.h>
#include<conio.h>
int main(){
int i,judge,sum=0;
int month;
float date,day;
printf("please input a date in 2009\n");
scanf("%f",&date);
month=(int)date;
day=(date-month)*100;
if(month==1)
sum=day;
else{
for(i=1;i<month;i++)
switch(i){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
sum+=31;
break;
case 2:
sum+=28;
break;
case 4:
case 6:
case 9:
case 11:
sum+=30;
break;
default:
break;
}
sum+=day;
}
judge=(sum-1)%7+4;
switch(judge){
case 8:
printf("Monday\n");
break;
case 9:
printf("Tuesday\n");
break;
case 10:
printf("Wednesday\n");
break;
case 4:
printf("Thursday\n");
break;
case 5:
printf("Friday\n");
break;
case 6:
printf("Saturday\n");
break;
case 7:
printf("Sunday\n");
break;
default:
break;
}
return 0;
}