Как определить день недели по введенной дате

int day=5,month=11,year=2000

#include <ctime>
#include <iostream>
 
int main() {
    int day = 5, month = 11, year = 2000;
    std::tm time_in = { 0, 0, 0, month, day, year - 1900 };
 
    std::time_t time_temp = std::mktime(&time_in);
    const std::tm * time_out = std::localtime(&time_temp);
 
    switch (time_out->tm_wday) {
    case 0:
        std::cout << "Sunday" << std::endl;
        break;
    case 1:
        std::cout << "Monday" << std::endl;
        break;
    case 2:
        std::cout << "Tuesday" << std::endl;
        break;
    case 3:
        std::cout << "Wednesday" << std::endl;
        break;
    case 4:
        std::cout << "Thursday" << std::endl;
        break;
    case 5:
        std::cout << "Friday" << std::endl;
        break;
    case 6:
        std::cout << "Saturday" << std::endl;
        break;
    }
 
    std::cin.get();
    return 0;
}

int WeekDay(int iYear,int iMonth,int iDay)
{
   // Month:  March   -  3 ... December - 12 of Current  Year
   //         January - 13,    February - 14 of Previous Year
   if (iMonth < 3) 
   { 
      // If January or February, adjust Month and Year
      iMonth += 12;
      --iYear;
   }
 
   int   N1 = (26 * (iMonth + 1)) / 10;    // Month Shift
   int   N2 = (125 * iYear) / 100;         // Leap Correction
 
   int   N3 = iDay + N1 + N2 - (iYear / 100) + (iYear / 400) - 1;
 
   return N3 % 7;
}

int day = 7, month = 9, year = 2017;

int tm_wday;  // days since Sunday - [0, 6]

    int day = 5, month = 11, year = 2000;    //    11,  it is December 
    std::tm time_in = { 0, 0, 0,   day,   month,   year - 1900 };
    //std::tm time_in = { 0, 0, 0, month, day, year - 1900 };   // error

struct tm {
        int tm_sec;     /* seconds after the minute - [0,59] */
        int tm_min;     /* minutes after the hour - [0,59] */
        int tm_hour;    /* hours since midnight - [0,23] */
        int tm_mday;    /* day of the month - [1,31] */
        int tm_mon;     /* months since January - [0,11] */
        int tm_year;    /* years since 1900 */
        int tm_wday;    /* days since Sunday - [0,6] */
        int tm_yday;    /* days since January 1 - [0,365] */
        int tm_isdst;   /* daylight savings time flag */
        };