#include <algorithm>
#include <vector>
#include <string>
#include <iterator>
#include <iostream>

// version 1
int main()
{
    // 1.
    std::vector<std::string> wishlist { "Book", "Bicycle", "Laptop", "Socks", "Decorations", "Candy" };

    // 2.
    std::cout << "What did you get? ";
    std::vector<std::string> gifts { std::istream_iterator<std::string>{std::cin},
                                     std::istream_iterator<std::string>{} };

    // 3.

    // using std::set_difference
    std::sort(wishlist.begin(), wishlist.end());
    
    std::sort(gifts.begin(), gifts.end());

    wishlist.erase(std::set_difference(wishlist.begin(), wishlist.end(),
                                       gifts.begin(), gifts.end(),
                                       wishlist.begin()),
                   wishlist.end());

    // using std::remove_if + std::find
    // wishlist.erase(
    //     std::remove_if(wishlist.begin(), wishlist.end(),
    //                    [&gifts](std::string const& entry)
    //                    {
    //                        return std::find(gifts.begin(), gifts.end(), entry) != gifts.end();
    //                    }),
    //     wishlist.end());

    // 4.
    std::copy(wishlist.begin(), wishlist.end(), std::ostream_iterator<std::string>{std::cout, "\n"});
}