要求將一帶連結串列頭List head的單向連結串列逆序。

#include<stdio.h>


typedef struct _list_node{
	struct _list_node *next;
	int data;
}list_node;

void print_list(list_node *head)
{
	head = head->next;
	while(head)
	{
		printf("%d ", head->data);
		head = head->next;
	}

	printf("\n");
}

list_node *reverse_list(list_node *head)
{
	list_node *h = head->next;
	list_node *new_head = head;
	list_node *tail = NULL;

	while(h)
	{
		head = h->next;
		h->next = tail;
		tail = h;
		h = head;
	}

	new_head->next = tail;

	return new_head;
}

list_node *_reverse_list_recu(list_node *new_head, list_node *head)
{
	if (head->next == NULL) {
		new_head->next = head;
		return head;
	}
	list_node *t = _reverse_list_recu(new_head, head->next);
	t->next = head;
	return head;
}

list_node *reverse_list_recu(list_node *head)
{
	list_node *t = _reverse_list_recu(head, head->next);
	t->next = NULL;
	return head;
}

int main(int argc, char *argv[])
{
	int i;
	list_node *head, *t, *tail;
	head = (list_node *)malloc(sizeof(list_node));
	tail = head;

	for (i = 0; i < 10; i++)
	{
		t = (list_node *)malloc(sizeof(list_node));
		t->data = i;
		t->next = NULL;
		tail->next = t;
		tail = t;
	}

	print_list(head);

	reverse_list(head);

	print_list(head);

	reverse_list_recu(head);

	print_list(head);
	return 0;
}