C++利用静态成员构建链表

#include <IOSTREAM.H>

class Node
{
public:
	Node(int val, Node* next):val(val),next(next){}
	//~Node(){cout<<"del "<<val<<endl;}
	static void showAll();//打印全部节点的值
	static void insertHead(int);//头插
	static void insertTail(int);//尾插
	static void delHead();//删头
	static void delTail();//删尾
	static void clear();//清空
protected:
	int val;
	Node *next;
	static Node *head;
private:
};

Node* Node::head = 0;

void Node::showAll(){//打印全部节点的值
	Node *p = head;
	while (p)
	{
		cout<<p->val<<" ";
		p = p->next;
	}
	cout<<endl;
}

void Node::insertHead(int val){//头插
	Node *p = new Node(val, head);
	head = p;
}

void Node::insertTail(int val){//尾插
	Node *p = new Node(val, 0);
	if (!head)
	{
		head = p;
		return;
	}
	Node *q = head;
	while (q->next)
	{
		q = q->next;
	}
	q->next = p;
}

void Node::delHead(){//删头
	Node *p = head;
	if (head)
	{
		head = head->next;
		delete p;
	}
}

void Node::delTail(){//删尾
	if (!head)
	{
		return;
	}
	if (!(head->next))
	{
		delete(head);
		head = NULL;
		return;
	}
	Node *p = head;
	while (p->next->next)
	{
		p = p->next;
	}
	delete(p->next);
	p->next = NULL;
}

void Node::clear(){//清空
	Node *p = head;
	Node *q = 0;
	head = 0;
	while (p)
	{
		q = p;
		p = p->next;
		delete q;
	}
}

void main(){
	Node::delHead();
	Node::delTail();
	Node::insertTail(2);
	Node::delTail();
	for (int i = 0; i < 10; i++)
	{
		Node::insertTail(i + 1);
	}
	Node::delTail();
	Node::showAll();
}