My list objects are being destroyed - c++

Question

list<Book> *books = new list<Book>;
list<Book>::iterator pos;
void Administrator::addBook()
{
Book *newBook = new Book();
cout << "Would you like to enter a book?" << endl;
cin >> userInput;
cout << endl;
if (userInput == "yes")
{
cout << "What is the title of the book you want to enter?" << endl;
cin >> title;
cout << "What is the author of the book you want to enter?" << endl;
cin >> author;
cout << "What is the ISBN of the book you want to enter?" << endl;
cin >> ISBN;
cout << endl;
newBook->setTitle(title);
newBook->setAuthor(author);
newBook->setISBN(ISBN);
newBook->setAvailability(true);
books->push_back(*newBook);
}
}
*****************
I really need help with this, i have received a few answers today but none have helped me with this problem. This is my admin class. It creates books on the heap and stores them in an stl::list
void Guest::searchBook(Book* search)
{
string searchBook;
cout << "What book would you like to search for?" << endl;
cin >> searchBook;
printBookDetails();
}
This is my Guest class, what i would like to do here is to search through the list of books i created in my Administrator class but when it goes into the function printBookDetails, my list contains no elements, im assuming they've been destroyed.
Administrator* admin1 = new Administrator("jayfitz91", 24681357);
Guest* guest1 = new Guest("guest", 0000);
void main()
{
//Everything here works fine
admin1->addBook();
admin1->addBook();
admin1->makeAvailable();
admin1->printBookDetails();
//My list is destroyed at this point and it returns nothing
guest1->printBookDetails();
My Guest class inherits the printBookDetails from my Administrator class
All of the admin functions work but as soon as it gets to guest, the elements disappear.
Is there anyway i can get around this? The help would greatly be appreciated

Answer 1

Thanks to #OldProgrammer, i realised i had to return the list of books from my Admin class and pass it through as a parameter to my printBookDetails method in my guest class:
//Admin class
//Now returning a list
list<Book> Administrator::addBook()
{
Book *newBook = new Book();
cout << "Would you like to enter a book?" << endl;
cin >> userInput;
cout << endl;
if (userInput == "yes")
{
cout << "What is the title of the book you want to enter?" << endl;
cin >> title;
cout << "What is the author of the book you want to enter?" << endl;
cin >> author;
cout << "What is the ISBN of the book you want to enter?" << endl;
cin >> ISBN;
cout << endl;
newBook->setTitle(title);
newBook->setAuthor(author);
newBook->setISBN(ISBN);
newBook->setAvailability(true);
books->push_back(*newBook);
}
return *books;
}
//Guest class function
void Guest::printBookList(list<Book> *tempList)
{
pos = tempList->begin();
for (pos = tempList->begin(); pos != tempList->end(); ++pos)
{
cout << pos->getTitle() << "\n"
<< pos->getAuthor() << "\n"
<< pos->getISBN() << "\n"
<< pos->getAvailability() << "\n"
<< "******************************" << endl;
}
}
//Main class function
//Create a temporary variable for the list
list<Book> tempList;
//pass it through to the method
guest1->printBookList(&tempList);

Answer 2

First off, you don't have to dynamically create your list object.
list<Book> books = new list<Book>();
You do this because
you have less responsibility: you don't have to release the resources contained by books. It will automatically be released.
list is a stl container, which means it automatically handles dynamic allocations.
This is different if you use an dynamically allocated array...
I think your list is "gone" is because Guest and Administrator has two entirely different list.
To solve this issue, you should grant access to the book list that Administrator has to your Guest.
Or extract out the book list and store it in another class that allow access to the list to both Administrator and Guest.