class elem
{
public:
  elem ();
  virtual ~ elem ();

public:
  inline elem * get_next ()
  {
    return pnext;
  }
  elem *set_next (elem * ael);
  elem *insert_after (elem * ael);
  virtual void print ()
  {
    if (pnext)
      pnext->print ();
  }
  inline elem *invert (elem * new_pnext = 0)
  {
    elem *old_pnext = pnext;
    pnext = new_pnext;
    if (old_pnext)
      return old_pnext->invert (this);
    else
      return this;
  }


private:
  elem * pnext;
};


class elem_int:public elem
{
public:
  elem_int (int val = 0)
  {
    my_val = val;
    cout << "kontruktor elem_int, ustawiona wartosc: " << my_val << endl;
  }
   ~elem_int ()
  {
    cout << "destruktor elem_int, przechowywana wartosc: " << my_val << endl;
  }

public:
  int set_val (int val)
  {
    return my_val = val;
  }
  int get_val ()
  {
    return my_val;
  }
  void print ()
  {
    cout << my_val << endl;
    elem::print ();
  }
private:
  int my_val;
};

class elem_str:public elem
{
public:
  elem_str (char *val = 0);
   ~elem_str ();
  void print ()
  {
    cout << my_val << endl;
    elem::print ();
  }
private:
  char *my_val;
};


class elem_float:public elem
{
public:
  elem_float (float val = 0)
  {
    my_val = val;
    cout << "kontruktor elem_float, ustawiona wartosc: " << my_val << endl;
  }
   ~elem_float ()
  {
    cout << "destruktor elem_float, przechowywana wartosc: " << my_val <<
      endl;
  }

public:
  float set_val (float val)
  {
    return my_val = val;
  }
  float get_val ()
  {
    return my_val;
  }
  void print ()
  {
    cout << my_val << endl;
    elem::print ();
  }
private:
  float my_val;
};