#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
class date {
    int year;
    int month;
    int day;
    static const int length[13];
public:
    date(int m, int d, int y);
    date(); // New no-argument constructor
    void print() const;
    void next(int n);
    void next();
    int dayOfYear() const; // New function to return day of the year
    friend int distance(const date& d1, const date& d2); // Friend function
};
int main() {
    try {
        const date independenceDay {7, 4, 1776};
        independenceDay.print();
        cout << " is Independence Day.\n";

        const date today; // Using the new constructor
        today.print();
        cout << " is today.\n";

        const date xmas {12, 25, 2025};
        cout << xmas.dayOfYear() << "\n"; // Should print 359

        const date d1 {1, 1, 2025};
        const date d2 {12, 31, 2025};
        cout << "Distance between Jan 1 and Dec 31: " << distance(d1, d2) << " days\n";
        
        const date summer {6, 20, 2025};  // First day of summer
        const int dist {distance(summer, today)};
        cout << "Only " << dist << " days till summer.\n";
    }
    catch (invalid_argument e) {
        cerr << e.what() << "\n";
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}
const int date::length[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
date::date(int m, int d, int y) {
    year = y;
    if (m < 1 || m > 12) throw invalid_argument("bad month");
    month = m;
    if (d < 1 || d > length[month]) throw invalid_argument("bad day of the month");
    day = d;
}
date::date() {
    time_t t = time(nullptr);
    tm* p = localtime(&t);
    year = p->tm_year + 1900;
    month = p->tm_mon + 1;
    day = p->tm_mday;
}
void date::print() const {
    cout << month << "/" << day << "/" << year;
}
void date::next(int n) {
    for (int i = 0; i < n; ++i) {
        next();
    }
}
void date::next() {
    if (day < length[month]) {
        ++day;
    } else {
        day = 1;
        if (month < 12) {
            ++month;
        } else {
            month = 1;
            ++year;
        }
    }
}
int date::dayOfYear() const {
    int dayCount = day;
    for (int i = 1; i < month; ++i) {
        dayCount += length[i];
    }
    return dayCount;
}
int distance(const date& d1, const date& d2) {
    int days1 = d1.dayOfYear() + (d1.year * 365);
    int days2 = d2.dayOfYear() + (d2.year * 365);
    return days1 - days2;
}