#include <iostream>
#include <iomanip>                      //for setw()
using namespace std;
////////////////////////////////////////////////////////////////
class Time
{
private:
	int hrs, mins, secs;
public:
	Time()                            //no-arg constructor
	{
		hrs = mins = secs = 0;
	}
	//--------------------------------------------------------------
	Time(int h, int m, int s)         //3-arg constructor
	{
		hrs = h; mins = m; secs = s;
	}
	//--------------------------------------------------------------
	void display()                    //format 11:59:59
	{
		cout.fill('0');                //with leading zeros
		cout << hrs
			<< ':' << setw(2) << mins
			<< ':' << setw(2) << secs;
	}

	Time operator +(const Time &s){
		int newh, newm, news;
		news = secs + s.secs;
		newm = mins + s.mins;
		newh = hrs + s.hrs;
		while (news >= 60){
			newm++;
			news -= 60;
		}
		while (newm >= 60){
			newh++;
			newm -= 60;
		}
		if (newh >= 24){
			newh = newh % 24;
		}
		return Time(newh, newm, news);
	}

	Time& operator --(){
		secs--;
		if (secs < 0){
			secs += 60;
			mins--;
		}
		if (mins < 0){
			mins += 60;
			hrs--;
		}
		if (hrs < 0){
			hrs += 24;
		}
		return *this;
	}

	Time& operator ++(){
		secs++;
		if (secs >= 60){
			secs -= 60;
			mins++;
		}
		if (mins >= 60){
			mins -= 60;
			hrs++;
		}
		if (hrs >= 24){
			hrs -= 24;
		}
		return *this;
	}

	Time operator --(int){
		Time Pom = *this;
		secs--;
		if (secs < 0){
			secs += 60;
			mins--;
		}
		if (mins < 0){
			mins += 60;
			hrs--;
		}
		if (hrs < 0){
			hrs += 24;
		}
		return Pom;
	}

	Time operator ++(int){
		Time Pom = *this;
		secs++;
		if (secs >= 60){
			secs -= 60;
			mins++;
		}
		if (mins >= 60){
			mins -= 60;
			hrs++;
		}
		if (hrs >= 24){
			hrs -= 24;
		}
		return Pom;
	}

};  //end class time
////////////////////////////////////////////////////////////////
int main()
{

	Time time1(5, 59, 59);               //creates and initialze
	Time time2(4, 0, 1);                 //   two times
	Time time3,time4;                          //create another time
	time3 = time1 + time2;               //add two times
	cout << "\nSum = "; time3.display(); //display result
	time4 = --time3;
	cout << "\nPrefix decr time4 = "; time4.display();
	cout << "\nPrefix decr time3 = "; time3.display();
	time4 = ++time3;
	cout << "\nPrefix incr time4 = "; time4.display();
	cout << "\nPrefix incr time3 = "; time3.display();
	cout << "\nNo change   = "; time3.display();
	time4 = time3--;
	cout << "\nPostfix decr time4 = "; time4.display();
	cout << "\nPostfix decr time3 = "; time3.display();
	time4 = time3++;
	cout << "\nPostfix incr time4 = "; time4.display();
	cout << "\nPostfix incr time3 = "; time3.display();
	cout << "\nNo change    = "; time3.display();
	cout << endl;
	return 0;
}