int main(int argc, char** argv) {
    int userChoice;
    while(userChoice != 4)
    {
        cout << "1.Add a book to yout cart" << endl;
        cout << "2.Delete a book from your cart" << endl;
        cout << "3.Display the books in your cart" <<endl;
        cout << "4.Exit" << endl;
        cout << endl << "Your choice: ";
        cin >> userChoice;

        if(userChoice == 1)
        {
            string title;
            cout <<"Title to add: ";
            cin >> title;
            Book mybook(title);
            mybook  = title;


        }
        if(userChoice == 3){
            Cart mycart;
            mycart.display();
        }
    }
}
using namespace std;
Cart& Cart::operator =(Book& obj){
    v.push_back(obj);
    return *this;
}
Book::Book(std::string bookTitle){
    setBookTitle(bookTitle);

This is my first time with overloaded operators and I feel like this is as far as I can get. I was supposed to prompt for a book title and add it to a vector using the compound operator =. I am getting a no-match operator error. Any help is appreciated. Thanks!