1  class A
       2  {
       3   protected:
       4    A();
       5    virtual ~A();
       6  };
       7  
       8  class B : virtual public A
       9  {
      10   public:
      11    B();
      12    virtual ~B();
      13  };
      14  
      15  class C
      16  {
      17   private:
      18    class C2 : public B
      19     {
      20     public:
      21       C2();
      22       virtual ~C2();
      23     };
      24  };