#include <iostream>

//--------------------------------------------------------------------------
// Data Definition
// ---------------
//  A date is a structure consisting of
//      - day as number
//      - month as number
//      - year as number
//--------------------------------------------------------------------------
struct Date
{
    int day;
    int month;
    int year;
};

//--------------
// Data Example
//--------------
Date date_1 = {  3, 4, 1900 };
Date date_2 = {  2, 7, 1945 };
Date date_3 = { 12, 4, 1996 };
Date date_4 = {  9, 5, 2000 };

//--------------
// Code Pattern
//--------------
// ... F(Date d)
// {
//     ... d.day ...
//     ... d.month ...
//     ... d.year ...
// }

//--------------------------------------------------------------------------
// Prototypes
//--------------------------------------------------------------------------
bool isLeapYear(Date d);
int nDay(Date d);
int leapDay(Date d);

//--------------------------------------------------------------------------
// main
//--------------------------------------------------------------------------
int main()
{
    std::cout << "isLeapYear(date_1) == " << std::boolalpha << isLeapYear(date_1) << "\n";
    std::cout << "isLeapYear(date_2) == " << std::boolalpha << isLeapYear(date_2) << "\n";
    std::cout << "isLeapYear(date_3) == " << std::boolalpha << isLeapYear(date_3) << "\n";
    std::cout << "isLeapYear(date_4) == " << std::boolalpha << isLeapYear(date_4) << "\n";

    std::cout << "leapDay(date_1) == " << leapDay(date_1) << "\n";
    std::cout << "leapDay(date_2) == " << leapDay(date_2) << "\n";
    std::cout << "leapDay(date_3) == " << leapDay(date_3) << "\n";
    std::cout << "leapDay(date_4) == " << leapDay(date_4) << "\n";

    std::cout << "nDay(date_1) == " << nDay(date_1) << "\n";
    std::cout << "nDay(date_2) == " << nDay(date_2) << "\n";
    std::cout << "nDay(date_3) == " << nDay(date_3) << "\n";
    std::cout << "nDay(date_4) == " << nDay(date_4) << "\n";
    return 0;
}

//--------------------------------------------------------------------------
// @description check whether a year is a leap year
// @param d a date
// @return true if d is a leap year, false otherwise
// @contract isLeapYear : Date -> boolean
// @example isLeapYear(date_1) == false
// @example isLeapYear(date_2) == false
// @example isLeapYear(date_3) == true
// @example isLeapYear(date_4) == true
//--------------------------------------------------------------------------
bool isLeapYear(Date d)
{
    return (d.year % 400 == 0) ||
            ((d.year % 100 != 0) && (d.year % 4 == 0));
}

//--------------------------------------------------------------------------
// @description calculate the leap day
// @param d a date
// @return 1 if d is a leap year, 0 otherwise
// @contract leapDay : Date -> int
// @example leapDay(date_1) == 0
// @example leapDay(date_2) == 0
// @example leapDay(date_3) == 1
// @example leapDay(date_4) == 1
//--------------------------------------------------------------------------
int leapDay(Date d)
{
    if (isLeapYear(d))
        return 1;
    else
        return 0;
}

//--------------------------------------------------------------------------
// @description calculate the number of days since the new year
// @param d a date
// @return the number of days since the new year
// @contract nDay : Date -> number
// @example nDay(date_1) == 31 + 28 + 31 + 3 == 93
// @example nDay(date_2) == 31 + 28 + 31 + 30 + 31 + 31 + 2 = 184
// @example nDay(date_3) == 31 + 29 + 31 + 12 == 103
// @example nDay(date_4) == 31 + 29 + 31 + 30 + 9 == 130
//--------------------------------------------------------------------------
int nDay(Date d)
{
    if (d.month == 1)
        return d.day;
    else if (d.month == 2)
        return 31 + d.day;
    else if (d.month == 3)
        return 31 + 28 + d.day + leapDay(d);
    else if (d.month == 4)
        return 31 + 28 + 31 + d.day + leapDay(d);
    else if (d.month == 5)
        return 31 + 28 + 31 + 30 + d.day + leapDay(d);
    else if (d.month == 6)
        return 31 + 28 + 31 + 30 + 31 + d.day + leapDay(d);
    else if (d.month == 7)
        return 31 + 28 + 31 + 30 + 31 + 31 + d.day + leapDay(d);
    else if (d.month == 8)
        return 31 + 28 + 31 + 30 + 31 + 31 + 31 + d.day + leapDay(d);
    else if (d.month == 9)
        return 31 + 28 + 31 + 30 + 31 + 31 + 31 + 31 + d.day + leapDay(d);
    else if (d.month == 10)
        return 31 + 28 + 31 + 30 + 31 + 31 + 31 + 31 + 30 + d.day + leapDay(d);
    else if (d.month == 11)
        return 31 + 28 + 31 + 30 + 31 + 31 + 31 + 31 + 30 + 31 + d.day + leapDay(d);
    else
        return 31 + 28 + 31 + 30 + 31 + 31 + 31 + 31 + 30 + 31 + 30 + d.day + leapDay(d);
}