单链表的反转

struct Node
{
	int Data;
	struct Node* next;
};

/**
* @brief 改函数实现单链表的反转
* @param[in] head 待反转的链表
*/
int reverse(Node* head)
{
	assert(head);
	if (NULL == head->next)
	{
		cout<<"listlink is Null!"<<endl;
		return -1;
	}

	Node* p = head->next;
	Node* q = p->next;

	// 考虑链表只有一个元素的情况
	if (NULL == q)
	{
		cout<<"The ListLink has only one element!"<<endl;
		return 0;
	}
	Node* r = q->next;

	p->next = NULL;

	while (r != NULL)
	{
		q->next = p;
		p = q;
		q = r;
		r = r->next;
	}

	q->next = p;
	head->next = q;
	return 0;
}