Compute intersection of two lists - Method 2

list_intersection_2.cpp

#include <iostream>
#include <string>
#include <set>
#include <unordered_set>
#include <list>
#include <algorithm>
using namespace std;

template <typename T> using intersection_set = set<reference_wrapper<T const>, less<T>>;

list<string> compare_list_warning(list<string> const& list_one, list<string> const& list_two)
{
  intersection_set<string> set_one, set_two;
  set_one.insert(begin(list_one), end(list_one));
  set_two.insert(begin(list_two), end(list_two));
  list<string> output;
  set_intersection(begin(set_one), end(set_one), begin(set_two), end(set_two), back_inserter(output), less<string>());
  return output;
}

int main() {
  list<string> common_names = compare_list_warning({"Roger", "Marcel", "Camille", "Hubert"}, {"Huguette", "Cunegond", "Marcelle", "Camille"});
  for(string const& common : common_names) {
    std::cout << "Common element: " << common << "\n";
  }
  std::cout << std::flush;
  return 0;
}