///////////////////////////////////////////////////////////////
// MT1-Q2.cpp - container for last N inputs                  //
//                                                           //
// Jim Fawcett, CSE687 - Object Oriented Deisgn, Spring 2019 //
///////////////////////////////////////////////////////////////

#include <list>
#include <iterator>

//// solution starts here ///////////////////////////////////////////

template <typename T>
class LastN {
public:
  using iterator = typename std::list<T>::iterator;
  using const_iterator = typename std::list<T>::const_iterator;

  LastN(size_t N) : N_(N) {}
  void add(const T& t) 
  { 
    list_.push_front(t); 
    if (list_.size() > N_)
      list_.pop_back();
  }
  iterator begin() { return list_.begin(); }
  iterator end() { return list_.end(); }
private:
  std::list<T> list_;
  size_t N_;
};

//// required solution ends here ////////////////////////////////////

#include <iostream>

template <typename T>
void show(LastN<T>& ln)
{
  std::cout << "\n  ";
  for (T item : ln)
    std::cout << item << " ";
}

int main()
{
  std::cout << "\n  MT1-Q2 - container for last N inputs";
  std::cout << "\n --------------------------------------\n";

  LastN<int> ln(5);
  for (int i = 0; i < 10; ++i)
  {
    ln.add(i);
    show(ln);
  }
  std::cout << "\n\n";
}