[C++] template을 사용하여 연결리스트 구현

/*
	SingleLinkedList, DoubleLinkedList 둘 다 사용할 수 없을까?
	DoubleLinkedList를 만들기 위한 사전작업.
*/

#include <iostream>
template<typename T>
class Node
{
public:
	Node(T element) {
		_data = element;
		next = NULL;
	}
	
	void addToNext(Node<T>* right) {
		right->next = this->next;
		this->next = right;
	}

	T _data;
	Node* next;
};

// DoubleLinekd List
template<typename T>
class DNode
{
public:
	DNode(T element) {
		_data = element;
		next = NULL;
		prev = NULL;
	}
	
	void addToNext(DNode<T>* right) {
		right->next = this->next;
		this->next = right;
		right->prev = this;
	}

	T _data;
	DNode<T>* next;
	DNode<T>* prev;
};


template<typename T=int, template<typename L> class NODE=Node >
class List
{
public:
	typedef T value_type;

	List() { 
		_head = new NODE<T>(0);
		_tail = NULL;
		_lastNode = _head;
	}
	
	void addNext(T element) {
		NODE<T>* elemNode = new NODE<T>(element);
		_lastNode->addToNext( elemNode );
		_lastNode = elemNode;
	}

	void addNext(NODE<T>* next) {
		_lastNode->addToNext( next );
		_lastNode = next;
	}

private:
	NODE<T>* _head;
	NODE<T>* _tail;

	NODE<T>* _lastNode;			// Last Node 
};


int main()
{
	List<int, Node> s;		// Single Linked List
	List<int, DNode> d;		// Double LInked LIst

	s.addNext(new Node<int>(10) );
	s.addNext(new Node<int>(11) );
	s.addNext(12);
	s.addNext(13);

	d.addNext(10);
	d.addNext(11);
	d.addNext(12);
	d.addNext(13);
	
	std::cout << std::endl;
}