#include <iostream.h>

class ListElem
{
public:
   int      value;      // Integer
   ListElem *next;      // Pointer used to make link    
};


void Print(ListElem *head)
{
   ListElem *p;

   p = head;             // Very important: start at first element

   cout << "List ==> ";
   while ( p != NULL )
   {
      cout << p->value << "  ";  // Access value stored in list element  
      p = p->next;               // Visit next element in list
   }
   cout << "\n\n";
}

/* -----------------------------------------------------------
   DeleteAtHead: Delete elem at start of linked list
   ----------------------------------------------------------- */
ListElem * DeleteAtHead(ListElem * head)
{
   ListElem *p2;

   if (head == NULL ) // Must make sure list is not empty
      return(NULL);

   p2 = head;    	// Delete p2
   head = p2->next;

   delete p2;    	// Return memory !!

   return(head);
}


/* -----------------------------------------------------------
   InsertAtHead: insert elem at start of linked list
		 Function returns head of new linked list
   ----------------------------------------------------------- */
ListElem * InsertAtHead(ListElem * head, ListElem * elem)
{
   elem->next = head;    // Make new list element points   
                         // to the start of "old list"   

   return(elem);	 // Return the new head
}

int main(int argc, char *argv[])
{
   ListElem *head, *p;
   void Print(ListElem *);
   ListElem *InsertAtHead(ListElem *, ListElem *);

   head = NULL;
   Print(head);

   p = new ListElem;
   p->value = 1500;
   head = InsertAtHead(head, p);
   Print(head);
   
   p = new ListElem;
   p->value = 2500;
   head = InsertAtHead(head, p);
   Print(head);
   
   p = new ListElem;
   p->value = 3500;
   head = InsertAtHead(head, p);
   Print(head);

   cout << endl;
   cout << "Delete head..." << endl;
   head = DeleteAtHead(head);
   Print(head);

   cout << "Delete head..." << endl;
   head = DeleteAtHead(head);
   Print(head);

   cout << "Delete head..." << endl;
   head = DeleteAtHead(head);
   Print(head);

   cout << "Delete head..." << endl;
   head = DeleteAtHead(head);
   Print(head);

   cout << "Delete head..." << endl;
   head = DeleteAtHead(head);
   Print(head);
}