양 방향 링크 와 순환 링크

typedef class Node
{
public:
	int data;
	Node *next;
	Node *pre;
}node;
class doublelist
{
public:
	doublelist()
	{
		
		head = NULL;
		count = 0;
	}
	~doublelist()
	{

	}

	Node *buyNode(int val,Node *next,Node * pre)
	{
		Node *p = new Node();
		p->data = val;
		p->next = next;
		p->pre = pre;

		return p;

	}
	void Insert(int pos, int val)
	{
		if (pos < 0 || pos > count)
		{
			cout << "the pos is error!" << endl;
			return;
		}
		if (head == NULL)
		{
			head = buyNode(val, NULL, NULL);
			count++;
			return;
		}
		if (pos == 0)
		{
			
			Node *s = buyNode(val, head, NULL);
			head = s;

		}
		else
		{
			Node *p = head;
			Node *q = p->next;
			while (pos - 1 > 0)
			{
				p = p->next;
				q = q->next;
				pos--;
			}
			Node *s = buyNode(val, q, p);
			p->next = s;

		}

		count++;
	}

	void Inserthead(int val)
	{
		Insert(0, val);
	}

	void Inserttail(int val)
	{
		Insert(count, val);
	}

	void Delete(int pos)
	{
		if (pos > count || pos < 0)
		{
			cout << "the pos is error!" << endl;
			return;
		}

		Node *p = head;
		Node *q = p->next;
		if (pos == 0)
		{
			free(p);
			head = q;
		}
		else if (pos == 1)
		{
			p->next = q->next;
			
		}
		else
		{
			while (pos - 1 > 0)
			{
				p = p->next;
				pos--;
			}

			p->pre->next = p->next;
		}

		count--;

	}
	void Deletehead()
	{
		Delete(0);
	}

	void Deletetail()
	{
		Delete(count);
	}

	int getcount()
	{
		return count;
	}
	void show()
	{
		Node *p = head;
		while (p != NULL)
		{
			cout << p->data << " ";
			p = p->next;
		}
		cout << endl;
	}
private:
	Node *head;
	int count;

};
int main()
{
	doublelist d;
	for (int i = 0; i < 10; i++)
	{
		d.Inserttail(i);
	}
	d.show();
	d.Delete(10);
	
	d.show();
	
	

	return 0;
}

class Node
{
public:
	Node *next;
	int data;
};
class CycleList
{
public:
	CycleList()
	{
		head = NULL;
		count = 0;
	}

	~CycleList()
	{

	}

	Node *buyNode(int val,Node *next)
	{
		Node* p = new Node();
		p->data = val;

		if (next == NULL)
		{
			p->next = p;
		}
		else
		{
			p->next = next;
		}


		return p;
	}

	void Insert(int pos, int val)
	{
		if (pos < 0 || pos > count)
		{
			cout << "the pos is error!" << endl;
			return;
		}
		if (head == NULL)
		{
			head = buyNode(val, NULL);
			count++;
			return;
		}
		Node *p = head;

		if (pos == 0)
		{
			pos = count;
			while (pos - 1> 0)
			{
				p = p->next;
				pos--;
			}
			Node *s = buyNode(val, p->next);
			p->next = s;
			head = s;
		}
		else
		{

			while (pos - 2 > 0)
			{
				p = p->next;
				pos--;
			}

			Node *s = buyNode(val, p->next);
			p->next = s;
		}
		
		count++;
	}

	void Inserthead(int val)
	{
		Insert(0, val);
	}

	void Inserttail(int val)
	{
		Insert(count, val);
	}

	void Delete(int pos)
	{
		if (pos < 0 || pos > count)
		{
			cout << "the pos is error" << endl;
			return;
		}

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

		if (pos == 1)
		{
			free(head);
			head = q;
		}
		else
		{

			while (pos - 2 > 0)
			{
				p = p->next;
				q = q->next;
				pos--;
			}
			p->next = q->next;
			free(q);
		}	
	}

	void Deletehead()
	{
		Delete(0);
	}

	void Deletetail()
	{
		Delete(count);
	}

	
	void show()
	{
		Node *p = head;
		Node *q = p;
		while (p->next != q)
		{
			cout << p->data << " ";
			p = p->next;
		}
		cout << p->data << endl;
	}
private:
	Node *head;
	int count;

};
int main()
{
	CycleList c;
	for (int i = 0; i < 3; i++)
	{

		c.Inserthead(i);
	}
	c.Insert(2, 10);
	c.show();

	c.Deletehead();
	c.show();
	return 0;
}