// Two-dimensional array example
#include <iostream>

// day_of_year: returns day of year:
int day_of_year( int month, int day, int year )
{
    // Table of the number of days in each month:
    static const int daytab[2][13] = {
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
        {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
    };

    int leap = year%4 == 0 && year%100 != 0 || year%400 == 0;
    for ( int i = 1; i < month; i++) {
        day += daytab[leap][i];
    }
    return day;
}

int main()
{
    for (;;) {
        int month;
        int day;
        int year;

        std::cout << "Enter M D Y: ";
        std::cin >> month;
        std::cin >> day;
        std::cin >> year;

        std::cout
            << "day of year: "
            << day_of_year( month, day, year )
            << std::endl
            ;
    }

    return 0;
}