write template for linkedlist

#ifndef __DLL_H__
#define __DLL_H__
template < class T >
class DLinkedList;
template < class Type >
class DNode{
  Type data;
  DNode < Type >* next;
  DNode < Type >* prev;
  DNode(Type data, DNode < Type > * prev = (DNode < Type > *)0, DNode < Type > * next = (DNode < Type > *)0);
  friend class DLinkedList < Type >;
};
template < class T >
class DLinkedList{
  DNode < T >* head;
  DNode < T >* cur;
  DNode < T >* tail;
public:
  DLinkedList(void);  
  ~DLinkedList(void);
  void Add(T data);
  bool IsEmpty(void);
  T Remove(void);
  bool GoNext(void);
  bool GoPrev(void);
  bool GoHead(void);
  bool GoTail(void);
  T Visit(void);
  T& operator[](T index);
};
#endif

#include "LL.h"
template < class T >
DNode < T > ::DNode(T data, DNode < T > * prev, DNode < T > * next){
  this->data = data;
  this->prev = prev;
  this->next = next;
}

template < class T >
DLinkedList < T > ::DLinkedList(void){
  head = tail = cur = (DNode <  T > *)0;
}
template < class T >
DLinkedList < T > ::~DLinkedList(void){
  while(!IsEmpty()) Remove();
}
template < class T >
void DLinkedList < T > ::Add(T data){
  DNode < T > * temp = new DNode < T > (data, tail);
  if(tail){
    tail->next = temp;
    tail = temp;
  }
  else{
    head = tail = cur = temp;
  }
}
template < class T >
bool DLinkedList < T > ::IsEmpty(void){
  return !cur;
}
template < class T >
int DLinkedList < T > ::Remove(void){
  T data = 0;
  return data;
}
template < class T >
bool DLinkedList < T > ::GoNext(void){
  bool res = false;
  if(cur != tail){
    cur = cur->next;
    res = true;
  }
  return res;
}
template < class T >
bool DLinkedList < T > ::GoPrev(void){
  bool res = false;
  if(cur != head){
    cur = cur->prev;
    res = true;
  }
  return res;
}
template < class T >
bool DLinkedList < T > ::GoHead(void){
  bool res = false;
  if(cur){
    cur = head;
    res = true;
  }
  return res;
}
template < class T >
bool DLinkedList < T > ::GoTail(void){
  bool res = false;
  if(cur){
    cur = tail;
    res = true;
  }
  return res;
}
template < class T >
T DLinkedList < T > ::Visit(void){
  return cur->data;
}
template < class T >
T& DLinkedList < T > ::operator[](T index){
  Node < T > * temp = head;
  if (cur == head){
    GoNext();
  } 
  head = head -> next;
  head -> prev = (Node < T > *) 0;
  T d = temp -> data;
  delete temp;
  return d;
}