class A
  {
  friend class B;
  private:
    int x;
    int y;
    void fnA(int v) { cout << "Called function A with v=" << v << endl; }
  public:
    A(int x, int y) { this -> x = x; this->y = y; }
    void publica(int v) { cout << "called public A with v=" << v << endl; }
  };

class B
  {
  friend class A;
  private:
    int a;
    int b;
    void fnb(int v){ cout << "Called function b with v=" << v << endl; }
  public:
    B(int a, int b) {
      this->a = a; this->b = b;
      }
    void publicb(int v) { cout << "called public b with v=" << v << endl; }
    // This function can access private members of A
	void showA(A *a) {
      cout << "Var x from class A=" << a->x << endl;
      }
  };
  
  // Code to show how this works.
      A testa(2, 3);
      B testb(6, 7);
      testb.publicb(11);
      testb.showA(&testa);