Library Management System

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

class Book {
public:
    string title;
    string author;
    bool isIssued;

    Book(string t, string a) : title(t), author(a), isIssued(false) {}
};

class Library {
private:
    vector<Book> books;

public:
    void addBook(const string& title, const string& author) {
        books.push_back(Book(title, author));
        cout << "Book added: " << title << endl;
    }

    void issueBook(const string& title) {
        for (auto& book : books) {
            if (book.title == title && !book.isIssued) {
                book.isIssued = true;
                cout << "Book issued: " << title << endl;
                return;
            }
        }
        cout << "Book not available or already issued!" << endl;
    }

    void returnBook(const string& title) {
        for (auto& book : books) {
            if (book.title == title && book.isIssued) {
                book.isIssued = false;
                cout << "Book returned: " << title << endl;
                return;
            }
        }
        cout << "This book was not issued or doesn't exist!" << endl;
    }

    void displayBooks() {
        cout << "Available Books in Library:\n";
        for (const auto& book : books) {
            cout << book.title << " by " << book.author;
            if (book.isIssued) cout << " (Issued)";
            cout << endl;
        }
    }
};

int main() {
    Library lib;

    lib.addBook("C++ Programming", "Bjarne Stroustrup");
    lib.addBook("The Catcher in the Rye", "J.D. Salinger");
    lib.addBook("To Kill a Mockingbird", "Harper Lee");

    lib.displayBooks();

    lib.issueBook("C++ Programming");
    lib.returnBook("C++ Programming");
    
    lib.displayBooks();

    return 0;
}