The library requires a class to store information about a book. Set up a class to hold data including title, author, year of publication, and a boolean variable to indicate if the book is in the library or if the book has been taken out. Create a method to load the data for one book. Create another method to display the data for a book. Create another method to check if a book is in the library or not. use c++ Write a main program to test your methods.

Sure, here's an example implementation in C++:

#include <iostream>
#include <string>

using namespace std;

class Book {
public:
    string title;
    string author;
    int year;
    bool in_library;

    void load_data() {
        cout << "Enter book title: ";
        getline(cin, title);
        cout << "Enter book author: ";
        getline(cin, author);
        cout << "Enter year of publication: ";
        cin >> year;
        cout << "Is the book in the library? (1 for yes, 0 for no): ";
        cin >> in_library;
    }

    void display_data() {
        cout << "Title: " << title << endl;
        cout << "Author: " << author << endl;
        cout << "Year of publication: " << year << endl;
        if (in_library) {
            cout << "Status: available" << endl;
        } else {
            cout << "Status: taken out" << endl;
        }
    }

    bool is_in_library() {
        return in_library;
    }
};

int main() {
    Book book;
    book.load_data();
    book.display_data();
    cout << "Is the book in the library? " << book.is_in_library() << endl;
    return 0;
}

In this implementation, the `Book` class has four member variables: `title`, `author`, `year`, and `in_library`. The `load_data` method prompts the user to enter information for each of these variables. The `display_data` method outputs the book's information to the console. The `is_in_library` method returns the `in_library` variable. Finally, the `main` function creates a `Book` object, calls its `load_data` method to populate its member variables, calls its `display_data` method to output its information, and calls its `is_in_library` method to check if it's in the library.