void reverse_recurse(LIST_ITEM ** head) {
LIST_ITEM * first;
LIST_ITEM * other;
if (*head == NULL) {
fprintf(stderr, "%s:%d head null\n", __FUNCTION__, __LINE__);
return;
}
first = *head;
other = first->next;
if (other == NULL) {
fprintf(stderr, "%s:%d list is single element\n", __FUNCTION__,
__LINE__);
return;
}
reverse_recurse(&other);
/*
* NULL -- [0] -- [1] -- [2]
* f o
* f <- o
* <- f <- o
*/
first->next->next = first;
first->next = NULL;
// reset head
*head = other;
}
int reverse_recurse(struct Node *head)
{
if (head == NULL) {
return 0;
}
if (head->next == NULL) {
return head->data;
}
int data = reverse_recurse(head->next);
printf("%d ", data);
return head->data;
}
int main(int argc, char *argv[])
{
int choice;
int n;
int p;
struct Node *head = NULL;
while(1)
{
choice = menu();
switch(choice)
{
case 0: return 0;
case 1: printf("Enter number: ");
scanf("%d", &n);
Append(&head, n);
break;
case 2: Display(head);
break;
case 3: printf("Enter number: ");
scanf("%d", &n);
printf("Enter position: ");
scanf("%d", &p);
Insert(&head, n, p);
break;
case 4: printf("Enter number: ");
scanf("%d", &n);
Delete(&head, n);
break;
case 5: reverse(&head);
Display(head);
break;
case 6: reverse_recurse(head);
break;
default:return 0;
}
}
return 0;
}
/*
* uncomment lines in body for recursive or iterative
*/
void reverse(LIST_ITEM ** head) {
reverse_recurse (head);
//reverse_iterate (head);
}
