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

typedef struct list {
    char *str;
    struct list *next;
    struct list *prev;
} list;

int
main (void)
{
    unsigned int i;
    list *start, *current, *end;

    start = NULL;

    for (i = 0; i < 10; i++)
      {
        list *chunk;
        chunk = malloc (sizeof (list));
        chunk->str = malloc (8);
        sprintf (chunk->str, "hello-%d", i);

        if (!start)
          {
            start = current = chunk;
            start->prev = NULL;
          }
        else
          {
            list *tmp;
            tmp = current;
            current->next = chunk;
            current = current->next;
            current->prev = tmp;
          }
      }

    end = current;
    current = start;

    while (current)
      {
        puts (current->str);
        current = current->next;
      }

    current = end;

    while (current)
      {
        puts (current->str);
        current = current->prev;
      }

    current = start;

    while (current)
      {
        list *tmp;
        tmp = current->next;
        free (current->str);
        free (current);
        current = tmp;
      }

    exit (EXIT_SUCCESS);
}