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Hi, I'm working on a quick sort for double linked list. All work except the first item. I don't know what is wrong. Can u plz help me find the error? Here is my code.

```
dlist_t* quick_sort(dlist_t* list)
{
dlnode_t *tnode = NULL, *first = NULL, *last = NULL;
first = list->head;
last = list->foot;
tnode = list->head;
printf("Before Sort=");
while (tnode != NULL)
{
printf(" %d ", *((int *) tnode->data));
tnode = tnode->next;
}
printf("\n\n");
quick_sorting(list, first, NULL);
return list;
}
void quick_sorting(dlist_t *list, dlnode_t *less, dlnode_t *greater)
{
dlnode_t *tnode= NULL, *pivot = NULL, *i, *next, *temp = NULL, *last = NULL;
pivot = less -> next;
temp = pivot;
last = greater ? greater->next : NULL;
if (less == greater || less->next == greater)
return;
for(i = pivot->next; i != last; i = next)
{
next = i->next; /*n = pivot -> next -> next*/
list_detach(list, i);
if ((cmp_int(i -> data, pivot-> data) == SMALLER))
list_insert_after(less, i);
else
list_insert_after(pivot, temp == pivot ? (temp = i) : i);
tnode = list->head;
printf("Sorting=");
while (tnode != NULL)
{ if(tnode == pivot) printf("->");
printf(" %d ", *((int *) tnode->data));
tnode = tnode->next;
}
printf("\n\n");
}
quick_sorting(list, pivot, temp);
quick_sorting(list, less, pivot -> prev);
}
void list_insert_after(dlnode_t *p,dlnode_t *n)
{
dlnode_t *next = NULL;
n->prev = p;
n->next = p->next;
if (p->next)
next = p -> next;
next->prev = n;
p->next = n;
}
void list_detach(dlist_t *list,dlnode_t *n)
{
dlnode_t *prev = NULL;
if (n != list->head)
{
prev = n->prev;
prev->next = n->next;
if (n->next)
n->next->prev = n->prev;
}
else
printf("Tried to detach head!");
}
```