#include <stdio.h>
#include <stdlib.h>


struct Node
{
   int          item;
   struct Node *next;
};

void printList(struct Node *p);
struct Node *addFirst(struct Node *h, int x);
struct Node *removeFirst(struct Node *h);


int main()
{
   struct Node *head = NULL;
   int k;

   // Insert 
   for (k = 1; k < 10; k++ )
   {
      head = addFirst(head, k);
//    printList(head);
   }      

   // Delete
   printList(head);

   for (k = 1; k < 10; k++ )
   {
      head = removeFirst(head);
      printList(head);
   }      

}


// Remove the first node from the list at h
struct Node *removeFirst(struct Node *h)
{
   struct Node *ret;

   if ( h == NULL )
      return h;		// Return NULL

   ret = h->next;	// Save return value
   free(h);		// De-allocate deleted node

   return ret;
}


// Inserts a new node containg x
// at the beginning of the list at h

struct Node *addFirst(struct Node *h, int x)
{
   struct Node *newNode = malloc( sizeof(struct Node) );

   newNode->item = x;  // Store x
   newNode->next = h;  // Make it point to h

   return newNode;
}



void printList(struct Node *p)
{
   while ( p != NULL )
   {
      printf("%d -> ", p->item);
      p = p->next;
   }
   printf("[NULL]\n");
}