What is operator+ (MyTime)?

While overloading binary operator as a member function, the first operand invokes the member function and the second one is passed to the member function.
For eg:- when t1+t2 is requested, t1 invokes operator+ and t2 will be passed to a member function.

MyTime t3;
t3=t1+t2;     //t3=t1.operator+(t2);

To support the above operation, we can add the following member function to our class

MyTime operator+(const MyTime& ref) 
{ 
    int th,tm;
    th=this->hh+ref.hh;
    tm=this->mm+ref.mm;
    return MyTime(th,tm);   //temporaray unnamed objects
}


Complete Code

class MyTime {
  int hh;
  int mm;

  public:
  MyTime():hh(0),mm(0) { }
  MyTime(int h, int m) : hh(h), mm(m) {}
  MyTime(const MyTime &ref) : hh(ref.hh), mm(ref.mm) {}
  MyTime operator+(const MyTime &ref) {
    int tmins = mm + ref.mm; //TODO:tmins > 60
    int thrs = hh + ref.hh;
    // MyTime tmp(thhrs, tmins);
    //return tmp;
    return MyTime(thrs, tmins);
  }
  void display() const { std::cout << hh << ":" << mm << "\n"; }

};
int main() {
  MyTime t1(10,20);
  MyTime t2(1,15);
  MyTime t3;
  t3 = t1 + t2; // t1.operator+(t2)
  t3.display();

  return 0;
}