#include <stdio.h>

typedef struct linked_list
{
  struct linked_list *next;
  int                 data;

} linked_list;

linked_list  a_list[5];

void init_a_list ()
{
   int ii;
   for (ii=0; ii<4; ii++) {
      a_list[ii].next = &(a_list[ii+1]);
      a_list[ii].data = ii+1;
   }
   a_list[4].next = NULL;
   a_list[4].data = 5;
}

int example_4 (linked_list *head)
{
   int sum;

   sum = 0;
   while (head != NULL) {
      sum += head->data;
      head = head->next;
   }

   return sum;
}

int main ()
{
   init_a_list ();
   printf ("%d\n", example_4 (a_list));

   return 0;
}