没用求余过的

#include <iostream>
using namespace std;
int main(){
int n;
cin>>n;
int a= n+1;
while(a>7){
a-=7;
}
switch(a){
case 1:cout<<"monday"; break;
case 2:cout<<"tuesday"; break;
case 3:cout<<"wednesday"; break;
case 4:cout<<"thursday"; break;
case 5:cout<<"friday"; break;
case 6:cout<<"saturday"; break;
case 7:cout<<"sunday"; break;

}
return 0;

}