分别用递归和非递归方式实现

/*
*非递归实现
*@retval:NULL on fail,else on success
*/
link_t *link_reverse(link_t *head)
{
	link_t *cur = head;
	link_t *cur_r;
	link_t *cur_l = NULL;
	
	while( cur != NULL )
	{
		cur_r = cur->next;
		cur->next = cur_l;
		cur_l = cur;
		cur = cur_r;	
	}
	
	return cur_l;
}

link_t *link_reverse_r0(link_t *head,link_t **new_head)
{	
	assert( head != NULL );
	
	if( head->next == NULL )
	{
		*new_head = head;
		return head;
	}
	else
	{
		link_t *p = link_reverse_r0( head->next,new_head);
		p->next = head;
		return head;
	}
}

/*
*递归实现
*/
link_t *link_reverse_r(link_t *head)
{
	link_t *new_tail = head;
	link_t *new_head = NULL;
	link_reverse_r0(head,&new_head);
	new_tail->next = NULL;
	
	return new_head;	
}