The Child DL_CELL Class:

class VOID_DL_CELL : public VOID_CELL_CORE{
    friend class VOID_DLLIST;
    friend class VOID_CLLIST;   
    friend class VOIDCLLISTFIter;
    friend class VOIDCLLISTBIter;
    friend class VOIDDLLISTFIter;
    friend class VOIDDLLISTBIter;        
  public:
    VOID_DL_CELL(ACCESS_VOID *element_access_in);
    ~VOID_DL_CELL();
    Arbent load_all(VOID_DL_CELL *previous_in,Arbent x,VOID_DL_CELL *next_in)
                 {element = x; next = next_in,previous = previous_in;};
    Arbent load_previous_pointer(VOID_DL_CELL *previous_in)
         {previous = previous_in;};
    VOID_DL_CELL* get_previous(){return(previous);};
    VOID_DL_CELL* get_next(){ return(next);};
    VOID_DL_CELL* split(VOID_DL_CELL *A);
    VOID_DL_CELL* merge(VOID_DL_CELL *A1,VOID_DL_CELL *A2);
    VOID_DL_CELL* mergesort(VOID_DL_CELL *A);    
    istream& grab(istream& in);
    ostream& print(ostream& out) const; 
  protected:
    VOID_DL_CELL *next;
    VOID_DL_CELL *previous;  
  };