// timeclass4.cc
#include <iostream>
#include <string>
using namespace std;

class Time
{
  private:
    int Hours;   // 0 to 23
    int Minutes; // 0 to 59

  public:
    Time() {
      Hours = Minutes = 0;
    }
    Time(int hrs, int mins)
      :Hours(hrs),Minutes(mins) {
      TimeCheck();
    } 
    void printTime() {
      cout << Hours << " hours and " << Minutes << " minutes" << endl;
    }
    // do any rollovers necessary on hours or minutes
    void TimeCheck() {
      if (Minutes > 59) {
        Hours += Minutes / 60;
        Minutes = Minutes % 60;
      }
      if (Minutes < 0) {
        Hours -= (-Minutes / 60) + 1;
        Minutes = 60 - (-Minutes % 60);
      }
      if (Hours > 23) Hours = Hours % 23;
      if (Hours < 0) Hours = 24 - (-Hours % 24);
    }
    // += operator
    void operator += (const Time &otherTime) {
      Minutes += otherTime.Minutes;
      Hours += otherTime.Hours;
      TimeCheck();
    }
    // - operator
    void operator -= (const Time &otherTime) {
      Minutes -= otherTime.Minutes;
      Hours -= otherTime.Hours;
      TimeCheck();
    }
};

int main()
{
  Time T1(0, 0);
  cout << "T1(0, 0): ";
  T1.printTime();
  Time T2(2, 5);
  cout << "T2(2, 5): ";
  T2.printTime();
  T1 -= T2;
  cout << "T1 -= T2 = ";
  T1.printTime(); 
}