#include <cstdio>
#include <iostream>
using namespace std;

//stabilire daca year este an bisect
#define isleapyear(year) ((!(year % 4) && (year % 100)) || (!(year % 400) && (year % 1000)))

struct date {
    int year;
    int month;
    int day;
    int wday;
};

char *wdays[11]={"Luni","Marti","Miercuri","Joi","Vineri","Sambata","Duminica"};

int isdatevalid ( struct date);

void weekday( struct date &);

int main()
{
    int  month, day, year;
    struct date d;

    cout << "Introdu data in format: zz ll aaaa : ";
    cin >> d.day >> d.month >> d.year;
    if (isdatevalid(d)) {
        weekday(d);
        cout << "Ziua spatamanii de la aceasta data este: " << wdays[d.wday] << "\n";
    }
    else
        cout << d.day << "/" << d.month << "/" << d.year << " is not a valid date!";
    getchar();
    getchar();
    return 0;
}

//functie de verificare a validatatii datei introduse
int isdatevalid(struct date d)
{
  if (d.day <= 0) return 0 ;
  switch( d.month )
    {
      case 1  :
      case 3  :
      case 5  :
      case 7  :
      case 8  :
      case 10 :
      case 12 : if (d.day > 31) return 0 ; else return 1 ;
      case 4  :
      case 6  :
      case 9  :
      case 11 : if (d.day > 30) return 0 ; else return 1 ;
      case 2  :
        if ( d.day > 29 ) return 0 ;
      if ( d.day < 29 ) return 1 ;
      if (isleapyear(d.year)) return 1 ;   // an bisect
    else return 0 ;
    }
  return 0 ;
}

void weekday(struct date &d)
{
  int ix, tx, vx;

  switch (d.month) {
    case 2  :
    case 6  : vx = 0; break;
    case 8  : vx = 4; break;
    case 10 : vx = 8; break;
    case 9  :
    case 12 : vx = 12; break;
    case 3  :
    case 11 : vx = 16; break;
    case 1  :
    case 5  : vx = 20; break;
    case 4  :
    case 7  : vx = 24; break;
  }
  if (d.year > 1900)  // 1900 nu a fost an bisect
    d.year -= 1900;
  ix = ((d.year - 21) % 28) + vx + (d.month > 2);
  tx = (ix + (ix / 4)) % 7 + d.day;
  d.wday =  tx % 7;
}