#include <stdio.h>
#define NODES 4
typedef struct list_head {
	struct node* head;
	struct node* tail;
} list_head;

typedef struct node {
	struct node* next;
	int value;
} node;

node n[NODES];

list_head init_empty_list()
{
	list_head h;
	h.head = 0;
	h.tail = 0;
	return h;
}

list_head init_list()
{
	int i;
	list_head h;
	for (i=0; i<NODES-1; ++i) {
		n[i].next = &n[i+1];
		n[i].value = i+1;
	}
	n[NODES-1].next = 0;
	n[NODES-1].value = NODES;
	h.head = &n[0];
	h.tail = &n[NODES-1];
	return h;
}

void print_list(list_head h)
{
	node* p = h.head;
	while (p)  {
		printf("%d ", p->value);
		p = p->next;
	} 
	printf("\n");
}

list_head reverse_list(list_head h)
{
	list_head nh;
	if ((h.head == 0) || (h.head->next ==0)) {
		return h;
	}
	nh.head = h.head->next;
	nh.tail = h.tail;
	nh = reverse_list(nh);
	h.head->next = 0;
	nh.tail->next = h.head;
	nh.tail = h.head;
	return nh;
}
 
int main()
{
	list_head head;
	head = init_list();
	print_list(head);
	head = reverse_list(head);
	print_list(head);
	return 0;
}