// ConsoleApplication1.cpp : Этот файл содержит функцию "main". Здесь начинается и заканчивается выполнение программы.
//

#include <iostream>

using namespace std;

class Time {
public:
    int h, m, s;
    Time() {
        h = 0;
        m = 0;
        s = 0;
    }
    Time(int h, int m, int s) {
        if (h < 0 || m < 0 || s < 0) throw 1;
        this->h = (h + (m + s / 60) / 60) % 24;
        this->m = (m + s / 60) % 60;
        this->s = s % 60;
    }
    Time(const Time& T) {
        this->h = T.h;
        this->m = T.m;
        this->s = T.s;
    }
    ~Time() {}

    Time& operator--() {
        s -= 5;
        if (s < 0) {
            s = 60 + s;
            m--;
            if (m < 0) {
                m = 60 + m;
                h--;
                if (h < 0)
                    h = 24 + h;
            }
        }
        return *this;
    }
    Time operator--(int) {
        Time t(*this);
        s -= 5;
        if (s < 0) {
            s = 60 + s;
            m--;
            if (m < 0) {
                m = 60 + m;
                h--;
                if (h < 0)
                    h = 24 + h;
            }
        }
        return t;
    }
    void operator+(Time T) {
        s = (s + T.s);
        m = (m + T.m + s / 60);
        h = (h + T.h + m / 60) % 24;
        m %= 60;
        s %= 60;
    }
    friend Time& operator++(Time&);
    friend Time operator++(Time&, int);
    friend bool operator!=(Time, Time);
    friend ostream& operator<<(ostream&, Time);
    friend istream& operator>>(istream&, Time&);
};

Time& operator++(Time &T) {
    T.s += 5;
    T.m += T.s / 60;
    T.h += T.m / 60;
    T.h %= 24;
    T.m %= 60;
    T.s %= 60;
    return T;
}
Time operator++(Time &T, int) {
    Time t(T);
    T.s += 5;
    T.m += T.s / 60;
    T.h += T.m / 60;
    T.h %= 24;
    T.m %= 60;
    T.s %= 60;
    return t;
}

bool operator!=(Time T1, Time T2) {
    return (T1.h != T2.h || T1.m != T2.m || T1.s != T2.s);
}

ostream& operator<<(ostream& out, Time T) {
    out << T.h << ":" << T.m << ":" << T.s;
    return out;
}
istream& operator>>(istream& in, Time& T) {
    int h, m, s;
    in >> h >> m >> s;
    T = Time(h, m, s);
    return in;
}

int main() {
    Time t(0, 0, 3), v(23, 59, 59);
    try {
        Time e(-1, 20, 20);
    }
    catch (int) {
        cout << "Errror!\n";
    }
    cout << t++ << endl;
    cout << t << endl;
    t + v;
    cout << t << endl;
    cout << (t != v) << endl;
    cout << t << endl;
    cout << --t << endl;
    cout << t << endl;
    return 0;
}