#include <iostream.h> 

class Xyz
{  public:
     Xyz(int& a, int b)   // constructor
     : abc(a), ijk(b) {}  // must initialize
     void display()
     { cout << abc << " " << ijk << endl; }
     void increment() { abc += ijk; }
   private:
     int& abc;            // reference member
     int ijk;             // const member
};

void test_fn(Xyz obj)
{     obj.display();
      obj.increment();
      obj.display();
}

int main()
{   int u = 1, v = 20, w = 99, z = 500;
    Xyz r(u,v), s(w, z);
    r.display(); s.display();
    s = r;
    // test_fn(r); test_fn(s);
    // s.increase();
    r.display(); s.display();
    cout << "Now u = " << u
         << ", w = " << w << endl;
    // r.Xyz(v,z);    // re-initialize r
    // r.display(); r.increment();  
    // cout << "Now v = " << v << endl;
    return(0);
}