// ListNode Class Definition

#include <iostream>
using namespace std;

template <class Object>
class List;

template <class Object>
class ListNode
{
public:
   ListNode( const Object & theElement = Object(), ListNode * n = NULL )
      : element( theElement ), next(n) { }

   const Object & read() const
      { return (element); }

   const ListNode  getNext() const
      { return (next); } 

private:
   Object   element;
   ListNode *next;

   friend class List<Object>;
};

template <class Object>
class List
{
public:
   List() 
   {
      header = new ListNode<Object>;
      header->element = Object();
      header->next = NULL;
   }

   bool isempty() const
   {
      return (header->next == NULL);
   }

   void printList()
   {
      ListNode<Object> *lptr;
      lptr = header->next;
      if (lptr == NULL) 
         cout << "List is empty!\n";
      else
         while (lptr != NULL)
         {
            cout << lptr->element << "\n";
            lptr = lptr->next;
         }
   }

   void addAtFront(const Object & theElement = Object()) const
   {
      ListNode<Object>  *nptr;
      nptr = new ListNode<Object>;
      nptr->element = theElement;
      nptr->next = header->next;
      header->next = nptr;
   }
  
private:
   ListNode<Object> *header;
};

// Test Program


int main()
{
   // Test the ListNode class

   ListNode<int> node1;
   cout << node1.read() << " is the value in node1.\n";
   ListNode<int> node2(250, &node1);
   cout << node2.read() << " is the value in node2.\n";

   // Test the List class

   List<int> mylist;

   if ( mylist.isempty() )
      cout << "My list starts out empty.\n";

   mylist.printList();

   mylist.addAtFront(30);
   mylist.addAtFront(20);
   mylist.addAtFront(10);
   mylist.printList();

   cout << "The End\n";

   return (0);
}