#ifndef BOOK_H #define BOOK_H #include #include using namespace std;

class Book { private: int id; string title; string author; bool borrowed;

public: Book(int i, string t, string a);

int getId();
string getTitle();
bool isBorrowed();

void borrow();
void giveBack();

};

#endif #include "Book.h"

Book::Book(int i, string t, string a) { id = i; title = t; author = a; borrowed = false; }

int Book::getId() { return id; }

string Book::getTitle() { return title; }

bool Book::isBorrowed() { return borrowed; }

void Book::borrow() { borrowed = true; }

void Book::giveBack() { borrowed = false; } #ifndef USER_H #define USER_H

#include #include using namespace std;

class User { private: int id; string name; vector books;

public: User(int i, string n);

int getId();

void borrowBook(int bookId);
void returnBook(int bookId);

};

#endif #include "User.h"

User::User(int i, string n) { id = i; name = n; }

int User::getId() { return id; }

void User::borrowBook(int bookId) { books.push_back(bookId); }

void User::returnBook(int bookId) { for (int i = 0; i < books.size(); i++) { if (books[i] == bookId) { books.erase(books.begin() + i); break; } } } #ifndef LIBRARY_H #define LIBRARY_H

#include using namespace std;

#include "Book.h" #include "User.h"

class Library { private: vector books; vector users;

public: void addBook(Book b); void addUser(User u);

bool borrowBook(int userId, int bookId);
bool returnBook(int userId, int bookId);

};

#endif #include "Library.h"

void Library::addBook(Book b) { books.push_back(b); }

void Library::addUser(User u) { users.push_back(u); }

bool Library::borrowBook(int userId, int bookId) { for (int i = 0; i < users.size(); i++) { if (users[i].getId() == userId) { for (int j = 0; j < books.size(); j++) { if (books[j].getId() == bookId && !books[j].isBorrowed()) { books[j].borrow(); users[i].borrowBook(bookId); return true; } } } } return false; }

bool Library::returnBook(int userId, int bookId) { for (int i = 0; i < users.size(); i++) { if (users[i].getId() == userId) { for (int j = 0; j < books.size(); j++) { if (books[j].getId() == bookId && books[j].isBorrowed()) { books[j].giveBack(); users[i].returnBook(bookId); return true; } } } } return false; } #include using namespace std;

#include "Library.h"

int main() { Library lib;

lib.addBook(Book(1, "C++ Basics", "Bjarne"));
lib.addUser(User(1, "Alice"));

if (lib.borrowBook(1, 1))
    cout << "Book borrowed" << endl;

if (lib.returnBook(1, 1))
    cout << "Book returned" << endl;

return 0;

}