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

#define COUNT 10

struct linkedStruct
{
 int elem;
 struct linkedStruct*  next;
};
 
typedef struct linkedStruct linked;
typedef linked* linkedPtr; 

void insertAtFront (linkedPtr* hd, int val)
{
 linkedPtr ptr = (linkedPtr) malloc (sizeof(linked));
 ptr->elem = val;
 ptr->next = *hd;
 *hd = ptr;
}

void removeFromFront (linkedPtr* hd)
{
 linkedPtr ptr = *hd;

 if (ptr != NULL)
   {
    *hd = ptr->next;
    free (ptr);
   }
}

int getFirstValue (linkedPtr hd)
{
 if (hd != NULL)
   return hd->elem;
 else
   return -999;
}

void show (linkedPtr hd)
{
 while (hd != NULL)
   {
    printf ("%d, ", hd->elem);
    hd = hd->next;
   }
 printf ("\n");
}

int listLength (linkedPtr hd)
{
 int length = 0;
 while (hd != NULL)
   {
    length++;
    hd = hd->next;
   }
 return length;
}


int main (int argc, char**argv)
{
  linkedPtr head = NULL;
  int i;
  int temp;

  for (i = 0 ; i < COUNT; ++i)
    {
     temp = rand() % 100;
     printf ("In main(): temp: %6d\n", temp);

     insertAtFront (&head, temp);

     show (head);
     printf ("The list has %d nodes\n", listLength(head));
    }

  printf ("\n\nRemoving items from the list\n");
  for (i = 0 ; i < COUNT/2 ; i++)
    {
     int val = getFirstValue (head);
     printf ("The first item in the list is: %d\n", val);
     removeFromFront (&head);

     /* to help show what is going on */
     show (head);
     printf ("The list has %d nodes\n", listLength(head));
    }

  printf ("\n");


}