#ifndef _BOX_HPP_
#define _BOX_HPP_

template <typename T>
class Box {
  T e;
public:
  Box(T e);
  T get() const;
  void set(T e);
  template <typename U>
  friend std::ostream& operator<<(std::ostream& out, const Box<U>& t);
};

template <typename T>
Box<T>::Box(T e) {
  this->e = e;
}

template <typename T>
T Box<T>::get() const { return e; }

template <typename T>
void Box<T>::set(T e) { this->e = e; }

template <typename T>
std::ostream& operator<<(std::ostream& out, const Box<T>& t) {
  out << t.get();
  return out;
}
#endif