POJ.2080 Calendar

1.Problem
http://poj.org/problem?id=2080

2.Idea
Simulate exact date month year

3.Source

 const char wstr[][20] = { "Saturday","Sunday","Monday","Tuesday","Wednesday","Thursday","Friday" };  
 int days_of_year(int year)  
 {  
      if (year % 100 == 0) {  
           return year % 400 == 0 ? 366 : 365;  
      }  
      return year % 4 == 0 ? 366 : 365;  
 }  
 int days_of_month(int month, int year)  
 {  
      if (month == 2)  
           return days_of_year(year) == 366 ? 29 : 28;  
      int d;  
      switch (month)  
      {  
           case 1: case 3: case 5: case 7: case 8: case 10: case 12:   
                d = 31; break;  
           default:  
                d = 30;  
                break;  
      }  
      return d;  
 }  
 int main()  
 {  
      int n;  
      cin >> n;  
      while (n >= 0) {  
           int year, month, day, week;  
           week = n % 7;  
           year = 2000;  
           month = 1;  
           day = 1;  
           while (n) {  
                if (n >= days_of_year(year)) {  
                     n -= days_of_year(year);  
                     year++;  
                }  
                else if(n >= days_of_month(month, year)) {  
                     n -= days_of_month(month, year);  
                     month++;  
                }  
                else {  
                     day += n;  
                     n = 0;  
                }  
           }  
           cout << year << '-' << (month < 10 ? "0" : "") << month << "-" << (day < 10 ? "0" : "") << day << " " << wstr[week] << endl;  
           cin >> n;  
      }  
      return 0;  
 }