#include <stdlib.h>

typedef struct  s_chaine
{
  int                   data;
  struct s_chaine       *next;
  struct s_chaine       *prev;
}               t_chaine;

t_chaine        *add_to_end_list(t_chaine *foo, int data)
{
  t_chaine      *new;
  t_chaine      *tmp;

  new = malloc(sizeof(*new));
  new->data = data;
  new->next = NULL;
  new->prev = NULL;
  if (!foo)
    return (new);
  tmp = foo;
  while (tmp->next)
    tmp = tmp->next;
  tmp->next = new;
  new->prev = tmp;
  return (foo);
}

int     main(void)
{
  t_chaine      *my_chaine;

  my_chaine = NULL;
  my_chaine = add_to_end_list(my_chaine, 7);
  my_chaine = add_to_end_list(my_chaine, 8);
  my_chaine = add_to_end_list(my_chaine, 9);
  while (my_chaine->next)
  {
    printf("%d\n", my_chaine->data);
    my_chaine = my_chaine->next;
  }

  my_chaine = my_chaine->next;
  return (0);
}