class pre 
 { 
  public: 
   pre();
  ~pre(); 
  virtual void print()
  {
   cout << author << endl;
   cout << title << endl;
   cout << year << endl ;
  }    
   char	*author;
   char	*title;
   int	year;
 }
 
class book:public pre
 {
  public:
   book();
   ~book();
  void print()
   {
    cout << editor << endl;
    cout << publisher << endl;
    pre::print();
   }    
   char *editor;
   char *publisher;
 }
  
class inbook : public book
{
 public:
  inbook();
  ~inbook();
  void	print()
  {
   cout <<chapter <<endl;
   cout << pages <<endl;
   cout <<number<<ednl;
   book::print();
  }
  char *chapter;
  char *pages;
  char *number;
}

class article:public pre
{
 article();
 ~article();
 void	print()
  {
   pre::print();
   cout <<pages <<endl;
   cout <<number<<endl;
   cout <<jurnal<<end;
   -   || - 
  }
  
 char	*pages;
 char	*number;
 int    volumne;
 char 	*jurnal;
 char	*month;
}