Thread: 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.

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.
The bit about leading underscores is.

#ifndef HOLDING_H
would have been perfectly acceptable.

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.

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.