新人跪求一道题目答案，速度速度。。。要跪了！π_π

#include<stdio.h>
int main()
{
int day,p;
printf("enter the day:");
scanf("%d",&day);
if(day<1 || day >31)
{
printf("enter error!\n");
return 0;
}
p = day%7;
switch(p-1)
{
case 0:printf("Saturday\n");break;
case 1:printf("Sunday\n");break;
case 2:printf("Monday\n");break;
case 3:printf("Tuesday\n");break;
case 4:printf("Wednesday\n");break;
case 5:printf("Thursday\n");break;
case 6:printf("Friday\n");break;
}
return 0;
}
------这俩人肯定一起在考试------

今天在考什么，都跑到这来求助。