Library Management System

#include <bits/stdc++.h>
using namespace std;
class book 
{
    string title, author;
    int id;
    bool is_borrowed;
public:
    book(string t, string a, int i) : title(t), author(a), id(i), is_borrowed(0) {}
    int getId() { return id; }
    bool getStatus() { return is_borrowed; }
    void borrowBook() { is_borrowed = true; }
    void returnBook() { is_borrowed = false; }
    void print() 
    {
        cout << "=============================\n";
        cout << "Book ID : " << id << "\n";
        cout << "Title   : " << title << "\n";
        cout << "Author  : " << author << "\n";
        cout << "Status  : " << (is_borrowed ? "Borrowed" : "Available") << "\n";
        cout << "=============================\n\n";
    }
};
// --------------------------------------------------------
class member 
{
    string name;
    int id;
    vector<int> borrowed_books;
public:
    member(string s, int i) : name(s), id(i) {}
    int getId() { return id; }
    void borrowByMember(int bid) 
    {
        borrowed_books.push_back(bid);
        cout << name << " borrowed book (ID: " << bid << ")\n";
    }
    void returnBook(int bid) 
    {
        for (int i = 0; i < borrowed_books.size(); i++)
        {
            if (borrowed_books[i] == bid)
            {
                borrowed_books.erase(borrowed_books.begin() + i);
                cout << name << " returned book (ID: " << bid << ")\n";
                return;
            }
        }
        cout << name << " did not borrow book (ID: " << bid << ")\n";
    }
    void print()
    {
        cout << "=============================\n";
        cout << "Member ID : " << id << "\n";
        cout << "Name      : " << name << "\n";
        cout << "Borrowed  : ";
        if (borrowed_books.empty())
            cout << "None";
        else
        {
            for (auto b : borrowed_books)
                cout << b << " ";
        }
        cout << "\n=============================\n\n";
    }
};
// --------------------------------------------------------
class library
{
    vector<book> books;
    vector<member> members;
public:
    void add_book(int i, string s, string a)
    {
        books.push_back(book(s, a, i));
        cout << "Book \"" << s << "\" was added successfully.\n";
    }
    void add_member(int i, string s)
    {
        members.push_back(member(s, i));
        cout << "Member \"" << s << "\" was added successfully.\n";
    }
    void borrow_book(int mem, int bo)
    {
        for (auto &boo : books) 
        {
            if (boo.getId() == bo) 
            {
                if (boo.getStatus())
                {
                    cout << "Book (ID: " << bo << ") is already borrowed.\n";
                    return;
                }
                for (auto &memo : members) 
                {
                    if (memo.getId() == mem) 
                    {
                        memo.borrowByMember(bo);
                        boo.borrowBook();
                        return;
                    }
                }
                cout << "Member not found.\n";
                return;
            }
        }
        cout << "Book not found.\n";
    }
    void ret_book(int mem, int bo)
    {
        for (auto &boo : books) 
        {
            if (boo.getId() == bo) 
            {
                for (auto &memo : members)
                {
                    if (memo.getId() == mem) 
                    {
                        memo.returnBook(bo);
                        boo.returnBook();
                        return;
                    }
                }
                cout << "Member not found.\n";
                return;
            }
        }
        cout << "Book not found.\n";
    }
    void printBooks()
    {
        cout << "\n===== All Books =====\n";
        for (auto &b : books) b.print();
    }
    void printMembers()
    {
        cout << "\n===== All Members =====\n";
        for (auto &m : members) m.print();
    }
};
// --------------------------------------------------------
signed main()
{
    library lib;
    int choice;
    while (true) 
    {
        cout << "\n========= Library Menu =========\n";
        cout << "1) Add Book\n";
        cout << "2) Add Member\n";
        cout << "3) Borrow Book\n";
        cout << "4) Return Book\n";
        cout << "5) Print All Books\n";
        cout << "6) Print All Members\n";
        cout << "7) Exit\n";
        cout << "Please choose an option: ";
        cin >> choice;
        if (choice == 1) 
        {
            int id;
            string title, author;
            cout << "Enter Book ID: ";
            cin >> id;
            cin.ignore();
            cout << "Enter Book Title: ";
            getline(cin, title);
            cout << "Enter Book Author: ";
            getline(cin, author);
            lib.add_book(id, title, author);
        }
        else if (choice == 2) 
        {
            int id;
            string name;
            cin.ignore();
            cout << "Enter Member Name: ";
            getline(cin, name);
            cout << "Enter Member ID: ";
            cin >> id;
            lib.add_member(id, name);
        }
        else if (choice == 3)
        {
            int memid, boid;
            cout << "Enter Member ID: ";
            cin >> memid;
            cout << "Enter Book ID: ";
            cin >> boid;
            lib.borrow_book(memid, boid);
        } 
        else if (choice == 4)
        {
            int memid, boid;
            cout << "Enter Member ID: ";
            cin >> memid;
            cout << "Enter Book ID: ";
            cin >> boid;
            lib.ret_book(memid, boid);
        }
        else if (choice == 5) 
        {
            lib.printBooks();
        }
        else if (choice == 6) 
        {
            lib.printMembers();
        } 
        else if (choice == 7) 
        {
            cout << "Exiting program...\n";
            break;
        } 
        else 
        {
            cout << "Invalid choice, please try again.\n";
        }
    }
}