#include <iostream>
#include <ctime>    // For time() and localtime()
using namespace std;

class date {
public:
    // Data members to store month, day, and year.
    int month;
    int day;
    int year;

    // Static array to hold the number of days in each month (non-leap year).
    // Note: Index 0 is not used; months are 1-indexed.
    static const int length[13];

    // Constructor with three explicit arguments.
    date(int m, int d, int y) : month(m), day(d), year(y) { }

    // No-argument constructor that sets the date to today's date.
    date() {
        // Get current time.
        time_t now = time(nullptr);
        // Convert to local time structure.
        tm *lt = localtime(&now);
        // tm_mon is 0-indexed so add 1; tm_mday and tm_year (offset by 1900) give the day and year.
        month = lt->tm_mon + 1;
        day = lt->tm_mday;
        year = lt->tm_year + 1900;
    }

    // Function to print the date in MM/DD/YYYY format.
    void print() const {
        cout << month << "/" << day << "/" << year;
    }

    // Member function that calculates the day of the year (1 to 365).
    int dayOfYear() const {
        int sum = 0;
        // Sum the days in all months preceding the current month.
        for (int m = 1; m < month; ++m) {
            sum += length[m];
        }
        // Add the current day.
        sum += day;
        return sum;
    }

    // Friend function declaration to compute the distance in days between two dates.
    friend int distance(const date& d1, const date& d2);
};

// Define the static array for month lengths.
// For non-leap years: index 1 = January, 2 = February, ..., 12 = December.
const int date::length[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

// Friend function definition.
// Returns the difference in days: positive if d1 is later than d2, zero if the same, negative otherwise.
// For simplicity, if the dates are in different years, we adjust by assuming 365 days per year.
int distance(const date& d1, const date& d2) {
    if (d1.year == d2.year) {
        return d1.dayOfYear() - d2.dayOfYear();
    } else {
        // Calculate a rough difference by converting the year to days (this doesn't account for leap years)
        int days1 = d1.dayOfYear() + d1.year * 365;
        int days2 = d2.dayOfYear() + d2.year * 365;
        return days1 - days2;
    }
}

int main() {
    // Test the no-argument constructor: it should initialize to today's date.
    const date t; // Calls the new no-arg constructor.
    cout << "Today is ";
    t.print();    // Prints today's date.
    cout << ".\n";

    // Test the dayOfYear member function.
    const date xmas {12, 25, 2025}; // Christmas 2025.
    cout << "Christmas is day number " << xmas.dayOfYear() << " of the year.\n";

    // Test the friend function distance.
    const date summer {6, 20, 2025};  // First day of summer.
    const int dist {distance(summer, t)};
    cout << "Only " << dist << " days till summer.\n";

    return 0;
}