ABC Problem

My ABC is:

Code:

//holding.h

#ifndef _HOLDING_H
#define _HOLDING_H

#include <stdlib.h>
#include <iostream>
#include <fstream>

using namespace std;

class Holding{
      
      protected:
                
                char *title;
                int titleLength;
                int callNumber;
              
      public:
             
             Holding(char *, int);
             Holding(const Holding &);
             virtual ~Holding();
             
             virtual void print(ostream &) = 0;
             
      };

#endif

// holding.cpp

#include "holding.h"

Holding::Holding(char *tempTitle, int tempCallNumber){
                      
                      titleLength = strlen(tempTitle);
                      title = new char[titleLength + 1];
                      strcpy(title, tempTitle);
                      title[titleLength] = '\0';
                      
                      callNumber = tempCallNumber;
                      
                      }
Holding::Holding(const Holding &temp){
                       
                       titleLength = temp.titleLength;
                       title = new char[titleLength + 1];
                       strcpy(title, temp.title);
                       title[titleLength] = '\0';
                       
                       callNumber = temp.callNumber;
                       
                       }
Holding::~Holding(){
        
        delete [] title;
        
        }

My derived class is:

Code:

// Book.h

#ifndef _BOOK_H
#define _BOOK_H

#include <stdlib.h>
#include <iostream>
#include <fstream>

#include "holding.h"

class Book : Holding {
      
      protected:
                
                char * author;
                int authorLength;
                
      public:
             
             Book(char *, char *, int);
             Book(const Book &);
             virtual ~Book();
             
             virtual void print(ostream &);
             
      };

#endif

// Book.cpp

#include "book.h"

Book::Book(char *tempAuthor, char * title, int callNumber) : Holding(title, callNumber) {
                
                authorLength = strlen(tempAuthor);
                author = new char[authorLength + 1];
                strcpy(author, tempAuthor);
                author[authorLength] = '\0';
                
                }
Book::Book(const Book &temp) : Holding(temp) {
                 
                 authorLength = temp.authorLength;
                 author = new char[authorLength + 1];
                 strcpy(author, temp.author);
                 author[authorLength] = '\0';
                 
                 }
Book::~Book(){
        
        delete [] author;
        
        }
void Book::print(ostream &out){
        
        cout << "Book: " << author << " " << '\"' << title << '\"' << " " << callNumber << endl;
        out << "Book: " << author << " " << '\"' << title << '\"' << " " << callNumber << endl;
        
        }

My main is:

Code:

// library.h

#ifndef _LIBRARY_H
#define _LIBRARY_H

#include <stdlib.h>
#include <iostream>
#include <fstream>

#include "holding.h"
#include "holding.cpp"

#include "book.h"
#include "book.cpp"

#endif

// library.cpp

#include <iostream>
#include <fstream>
#include <stdlib.h>

#include "library.h"

ofstream csis;

int main(){
    
    csis.open("csis.dat");
    
    char type;
    char format;
    char callNumber[100];
    char author[100];
    char title[100];
    
    Book *book;
    Holding *Holdings[5];
    book = new Book("Jeremiah", "Loo", 125);
    Holdings[0] = book;
    }

In the end I'm getting this error:

Code:

'Holding' is an inaccessible base of 'Book'

I don't know why it's having trouble access it. I believe I clearly derived Book from Holding. Thanks for any suggestions or help.

You are using private inheritance. It should be:

Code:

class Book : public Holding

Incidentally, do not use names that begin with an underscore followed by an uppercase character. Those are reserved to the implementation for any use.

Thanks. I've been looking at that in my book and online but I'm so used to seeing class declarations that the extra "public" escaped my attention.

By the way:

#ifndef _HOLDING_H

Bad. Only the compiler is allowed to use identifiers starting with an underscore followed by an uppercase letter for its own private purposes.

Originally Posted by CornedBee

By the way:

#ifndef _HOLDING_H

Bad. Only the compiler is allowed to use identifiers starting with an underscore followed by an uppercase letter for its own private purposes.

No, not true. They are needed and are very important for a programmer to use.

http://www.fredosaurus.com/notes-cpp...sor/ifdef.html

> No, not true.
The bit about leading underscores is.

#ifndef HOLDING_H
would have been perfectly acceptable.

Ah, good info to know.

To be precise, identifiers beginning with an underscore, followed by another underscore or an uppercase letter, are reserved by the implementation. So _variable is okay, but __variable and _Variable are not.

If you want to be even more precise, identifiers that contain a double underscore anywhere in the name are reserved. So vari_able is ok, but vari__able is not.

I didn't know that. You learn something new every day.

And if you want to be yet more precise, identifiers starting with a single underscore followed by a lowercase letter or digit are reserved in the global namespace, i.e. you must not define a macro or global identifier (variable, function, type) with such a name.