include <algorithm>
  include <iostream>
  include <vector>
  using namespace std;
  
  // Function template to populate a container of ints.
  // The container must support push_back().
  template<typename Container>
  void populateContainer(Container& cont)
  {
    int num;
  
    while (true) {
      cout << "Enter a number (0 to quit): ";
      cin >> num;
      if (num == 0) {
        break;
      }
      cont.push_back(num);
    }
  }
  
  void print(int elem)
  {
    cout << elem << " ";
  }
  
  int main(int argc, char** argv)
  {
    vector<int> setOne, setTwo, setThree;
    cout << "Enter set one:\n";
    populateContainer(setOne);
    cout << "Enter set two:\n";
    populateContainer(setTwo);
  
    // set algorithms work on sorted ranges
    sort(setOne.begin(), setOne.end());
    sort(setTwo.begin(), setTwo.end());
  
    if (includes(setOne.begin(), setOne.end(), setTwo.begin(), setTwo.end())) {
      cout << "The second set is a subset of the first\n";
    }
    if (includes(setTwo.begin(), setTwo.end(), setOne.begin(), setOne.end())) {
      cout << "The first set is a subset of the second\n";
    }
  
    setThree.resize(setOne.size() + setTwo.size());
    vector<int>::iterator newEnd;
    newEnd = set_union(setOne.begin(), setOne.end(), setTwo.begin(),
                       setTwo.end(), setThree.begin());
    cout << "The union is: ";
    for_each(setThree.begin(), newEnd, &print);
    cout << endl;
  
    newEnd = set_intersection(setOne.begin(), setOne.end(), setTwo.begin(),
                              setTwo.end(), setThree.begin());
    cout << "The intersection is: ";
    for_each(setThree.begin(), newEnd, &print);
    cout << endl;
  
    newEnd = set_difference(setOne.begin(), setOne.end(), setTwo.begin(),
                            setTwo.end(), setThree.begin());
    cout << "The difference between set one and set two is: ";
    for_each(setThree.begin(), newEnd, &print);
    cout << endl;
  
    newEnd = set_symmetric_difference(setOne.begin(), setOne.end(), setTwo.begin(),
                                      setTwo.end(), setThree.begin());
    cout << "The symmetric difference is: ";
    for_each(setThree.begin(), newEnd, &print);
    cout << endl;
  
    return (0);
  }