c-resources/CPlusPlus20ForProgrammers-m.../examples/ch20/fig20_09-13/Book.cpp

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// Fig. 20.12: Book.cpp
// Book member-function definitions.
#include <fmt/format.h>
#include <iostream>
#include <memory>
#include <string>
#include <string_view>
#include "Author.h"
#include "Book.h"
Book::Book(std::string_view bookTitle) : title(bookTitle) {}
Book::~Book() {
std::cout << fmt::format("Destroying Book: {}\n", title);
}
// print the name of this Book's Author
void Book::printAuthorName() {
// if weakAuthorPtr.lock() returns a non-empty shared_ptr
if (std::shared_ptr<Author> authorPtr{weakAuthorPtr.lock()}) {
// show the reference count increase and print the Author's name
std::cout << fmt::format("Reference count for Author {} is {}\n",
authorPtr->name, authorPtr.use_count());
std::cout << fmt::format("The book {} was written by {}\n",
title, authorPtr->name);
}
else { // weakAuthorPtr points to NULL
std::cout << "This Book has no Author.\n";
}
}
/**************************************************************************
* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
* Pearson Education, Inc. All Rights Reserved. *
* *
* DISCLAIMER: The authors and publisher of this book have used their *
* best efforts in preparing the book. These efforts include the *
* development, research, and testing of the theories and programs *
* to determine their effectiveness. The authors and publisher make *
* no warranty of any kind, expressed or implied, with regard to these *
* programs or to the documentation contained in these books. The authors *
* and publisher shall not be liable in any event for incidental or *
* consequential damages in connection with, or arising out of, the *
* furnishing, performance, or use of these programs. *
**************************************************************************/