I don't know what to do with passed pointers in my non-default constructor

Question

I don't know how I should handle passed objects pointer in my non-default constructor. I am doing this program wrong because I feel like I don't know what I'm doing.

I've been stuck on this for a day and a half and I just don't understand it. I will post majority of my homework where I must use default constructor and non default constructor. I will also include the class diagram that I'm using so you can see how variables/classes/methods function.

What should I be doing with passed pointers inside of non-default constructor? I can't assign any values through here because it will tell me that its inaccessible. In this piece of code:

Book::Book(string title, Author *pAuthor, Publisher *pPublisher, double price)
    {
        setTitle(title);
        setPrice(price);
    }

Any idea how to use those pointers? Right now I can correctly pass everything by using default constructor, but I'm probably doing this wrong since I am using additional objects. Basically I shouldn't have 2 lines with Author author; and Publisher publisher; but I don't care at this point.

Please help!

Book.cpp file

#include <iostream>
#include <sstream>
using namespace std;

#include "Book.h"
#include "Publisher.h"
#include "Author.h"

class Book
{
    public:
        Book();
        Book(string title, Author *pAuthor, Publisher *pPublisher, double price);
        ~Book();
        void setTitle(string title);
        void setAuthorName(string first, string last);
        void setPublisher(string name, string address, string city);
        void setPrice(double price);
        string convertDoubleToString(double number);
        string getBookInfo();

    private:
        string title;
        double price;
        Author *pAuthor;
        Publisher *pPublisher;

    Author author;
    Publisher publisher;
};

Book::Book()
{
}

Book::Book(string title, Author *pAuthor, Publisher *pPublisher, double price)
{
    setTitle(title);
    setPrice(price);
}

Book::~Book()
{
}

void Book::setTitle(string  title)
{
    this->title = title;
}

void Book::setAuthorName(string first, string last)
{
    author.setFirstName(first);
    author.setLastName(last);
}

void Book::setPublisher(string name, string address, string city)
{
    publisher.setName(name);
    publisher.setAddress(address);
    publisher.setCity(city);
}

void Book::setPrice(double price)
{
    this->price = price;
}

string Book::convertDoubleToString(double number)
{
    return static_cast<ostringstream*>( &(ostringstream() << number) ) -> str();
}

string Book::getBookInfo()
{
    return title + "\n" + author.getFullName() + "\n" + publisher.getPublisherInfo() + "\n" + "$" + convertDoubleToString(price);
}

Main.cpp file:

#include <iostream>
#include <string>
using namespace std;

#include "Book.h"

int main()
{
    system("cls");

    cout << "Book 1" << endl;

    Author *pAuthor = new Author("John", "Doe");
    Publisher *pPublisher = new Publisher("Wrox", "10475 Crosspoint Blvd.", "Indianapolis");
    Book *pBook = new Book("Memory Management", pAuthor, pPublisher, 39.99);

    cout << pBook->getBookInfo() << endl;

    cout << endl << "Book 2" << endl;

    Book book;

    book.setTitle("Advanced C++ Programming");
    book.setAuthorName("Linda", "Smith");
    book.setPublisher("Microsoft Press", "One Microsoft Way", "Redmond");
    book.setPrice(49.99);

    cout << book.getBookInfo() << endl << endl;

    system("pause");

    return 0;
};

Author.cpp file:

#include <iostream>
#include <string>
using namespace std;

class Author
{
    public:
        Author();
        Author(string first, string last);
        string getFullName();
        void setFirstName(string first);
        void setLastName(string last);

    private:
        string firstName;
        string lastName;
};

Author::Author()
{
}

Author::Author(string first, string last)
{
    setFirstName(first);
    setLastName(last);
}

string Author::getFullName()
{
    return firstName + " " + lastName;
}

void Author::setFirstName(string first)
{
    this->firstName = first;
}

void Author::setLastName(string last)
{
    this->lastName = last;
}

Class Diagram:

Answer 1

You need to allocate enough memory to your pointer members to hold the data being passed through the pointers and then copy the data pointed by the passed pointer to your member pointer variables.

In short you need to perform a Deep Copy of the passed pointer members. So that your pointer members own the data to which they point.

EDIT:
Though the soultion you posted might seem to work, it still has problems:

Book::Book() 
{     
    pAuthor = new Author();     
    pPublisher = new Publisher(); 
} 

Dynamically allocates memory to the class pointer members, they indeed need their own memory allocation because your class should own and control the lifetime of these members.
You might want to have a look at Member Initializer Lists. However, the patameterized constructor of Book class which takes 4 parameters still does not allocate any memory. It still performs a shallow copy of pointers passed to it.

What is a shallow copy?

Shallow copy is nothing but simply pointing a pointer to some address.It means your pointer is not solely in control of the pointed object.If some other pointer which points to the same object deallocates the object(by calling `delete etc), then what you ar eleft with is a pointer pointing to something that does not exist anymore, a.k.a a dangling pointer.

This is what happens when you do:

Book::Book(string title, Author* pAuthor, Publisher* pPublisher, double price) 
{
    ....
    this->pPublisher = pPublisher;           
    this->pAuthor = pAuthor;     
    ....
}

What you need to avoid this situation is Deep Copy.

What is a Deep copy?

Deep Copy means, allocating your pointer a separate memory and then copying the contents of another pointer to memory of your own object(unlike in shallow copy).This separates the lifetime of the object pointed by your pointer separate from the lifetime of the pointer from which it was created.

For this to happen you should allocate separate memory to your pointer members and then the overloaded = operators of your classes Author and Publisher should copy each member of the respective classes. Have a look at copy and swap idiom for how to implement this correctly in C++.

Answer 2

Unless the assignment requires that you use pointer data members, the best solution is to simply remove them altogether, and modify the relevant constructor, which you can also improve by using an initialization list:

class Book {

  ....
 public:
  Book(std::string title, const Author& author, const Publisher& publisher, double price);
 private:
  // use some convention for private data member names, here trailing _
  std::string title_;
  double price_;
  Author author_;
  Publisher publisher_;

};

Book::Book(string title, const Author& author, const Publisher& publisher, double price)
 : title_(title), price_(price), author_(author), publisher_(publisher) 
{

}

Edit: since it seems to be a requirement to use pointers, and since the Book class has methods that attempt to modify the Author and Publisher, you need to make a deep copy of the object pointed to by the input pointers. This means dynamically allocating an object with new and assigning a pointer to it to one of your pointer data members. For example,

class A { .... }; // class with copy constructor

A* a1; // pointer to an A, points to nothing.
a = new A(); // a1 now points to dynamically allocated A. You are in charge of deleting!
A* a2(new A); // pointer to an A, initialized to point to dynamically allocated A.

But then you are in charge of deleting the dynamically allocated objects, and must modify your class to make copy constructing and assigning sensible, i.e. follow the rule of three. Hopefully you will see that using pointers in this particular case causes more problems than its worth.

Answer 3

After few minutes talking to my classmate I figured out that I was missing few vital lines of code.

I guess the problem with my question was that I don't understand pointers how I should have. After few tips from professor and classmates I knew that I was missing few lines of code within default and non-default constructor.

Here I will show what I was exactly looking for:

Main.cpp file:

#include <iostream>
#include <string>
using namespace std;

#include "Book.h"

int main()
{
    system("cls");

    cout << "Book 1" << endl;

    Author *pAuthor = new Author("John", "Doe");
    Publisher *pPublisher = new Publisher("Wrox", "10475 Crosspoint Blvd.", "Indianapolis");
    Book *pBook = new Book("Memory Management", pAuthor, pPublisher, 39.99);

    cout << pBook->getBookInfo() << endl;

    cout << endl << "Book 2" << endl;

    Book *book = new Book();

    book->setTitle("Advanced C++ Programming");
    book->setAuthorName("Linda", "Smith");
    book->setPublisher("Microsoft Press", "One Microsoft Way", "Redmond");
    book->setPrice(49.99);

    cout << book->getBookInfo() << endl << endl;

    system("pause");

    return 0;
};

Book.cpp file:

#include <iostream>
#include <sstream>
using namespace std;

#include "Book.h"

Book::Book()
{
    pAuthor = new Author();
    pPublisher = new Publisher();
}

Book::Book(string title, Author* pAuthor, Publisher* pPublisher, double price)
{
    this->title = title;
    this->price = price;

    this->pPublisher = pPublisher;
    this->pAuthor = pAuthor;
}

Book::~Book()
{
    delete pAuthor;
    delete pPublisher;
}

void Book::setTitle(string  title)
{
    this->title = title;
}

void Book::setAuthorName(string first, string last)
{
    pAuthor->setFirstName(first);
    pAuthor->setLastName(last);
}

void Book::setPublisher(string name, string address, string city)
{
    pPublisher->setName(name);
    pPublisher->setAddress(address);
    pPublisher->setCity(city);
}

void Book::setPrice(double price)
{
    this->price = price;
}

string Book::convertDoubleToString(double number)
{
    return static_cast<ostringstream*>( &(ostringstream() << number) ) -> str();
}

string Book::getBookInfo()
{
    return title + "\n" + pAuthor->getFullName() + "\n" + pPublisher->getPublisherInfo() + "\n" + "$" + convertDoubleToString(price);
}