What day is it

Description

Today is Saturday, 17th Nov,2007. Now, if i tell you a date, can you tell me what day it is ?       

              

Input

There are multiply cases.        One line is one case.        There are three integers, year(0<year<10000), month(0<=month<13), day(0<=day<32).       

              

Output

Output one line.        if the date is illegal, you should output "illegal". Or, you should output what day it is.       

        

Sample Input

2007 11 17

              

Sample Output

Saturday

 

 

注意这题细节很多，我是从0001年01月01日为周一考虑的。

#include <iostream>
#include <stdio.h>
#include <cstring>
using namespace std;
int a[]={0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int b[]={0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
char c[8][11]={"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
int panduan(int y)
{
    if((y%4==0 && y%100!=0) || y%400==0)
        return 1;
    return 0;
}
int main()
{
   int y, m, d, sum, i;
   while(cin>>y>>m>>d)
   {
      if(panduan(y))
      {
          if(d>b[m]||m==0||d==0)
            {
                cout << "illegal" << endl;
                continue;
            }
      }
      else
        {
            if(d>a[m]||m==0||d==0)
            {
                cout << "illegal" << endl;
                continue;
            }
        }
        sum=0;
        for (i=1; i<y; ++i)
            {
               if(panduan(i))
                sum += 366;
               else
                sum += 365;

            }
        for(int i = 0; i < m; ++i)
        {
            if(panduan(y))
                sum += b[i];
            else
                sum += a[i];

        }
        sum+=d;
        sum%=7;
        cout<< c[sum] << endl;
   }
   return 0;
}