list.cpp

#include <cstddef>

template <class T> class List {
public:
  typedef std::size_t size_type;
  typedef T value_type;
  List() : next(nullptr), val(0) {}
  explicit List(size_type n, const value_type& newVal = value_type());
  List(const List& l) { create(l); }
  List& operator=(const List&);
  ~List() { uncreate(); }
  bool empty() const { return next; }
  List* next;
  value_type val;
private:
  void create(const List& l);
  void uncreate();
};

template <class T>
List<T>::List(size_type n, const T& newVal)
{
  val = newVal;
  if (n < 1) {
    next = nullptr;
  } else {
    next = new List(n - 1, newVal);
  }
}

template <class T>
List<T>& List<T>::operator=(const List& rhs)
{
  if (&rhs != this) {
    uncreate();
    create(rhs);
  }
  return *this;
}

template <class T>
void List<T>::create(const List& l)
{
  val = l.val;
  if (l.next) {
    next = new List(*l.next);
  } else {
    next = nullptr;
  }
}

template <class T>
void List<T>::uncreate()
{
  if (next) {
    delete next;
    next = nullptr;
  }
}