class sample
{
private : 
  int x;
public :
  sample(int x =0)
  {
    this->x = x;
  }
};

sample::sample operator+(sample s)
{
  this->x = this->x + s.x;
  return *this;
}



  int  main()
    {
      sample s1(10);
      sample s2;
      s2 = s2 + s1;
      return 0;    
    }