Node實(shí)現(xiàn)：

	class NonCopyable//對(duì)象語義是拿來限制的	{	protected:		NonCopyable(){}	private: 		NonCopyable(const NonCopyable&);		const NonCopyable& Operator=(const NonCopyable&) = delete;	};注意：使用public繼承也是可以的，但是這個(gè)類并沒有實(shí)現(xiàn)他，相當(dāng)于是一個(gè)接口，對(duì)這種接口類的集成，我們一般使用private繼承。原理來自于    以前學(xué)的可以知道一個(gè)類在自己沒實(shí)現(xiàn)方法的時(shí)候默認(rèn)會(huì)生出八個(gè)默認(rèn)的函數(shù)（構(gòu)造、析構(gòu)、賦值、拷貝構(gòu)造、op*、op&、const op*、const op&），在對(duì)象生成的時(shí)候也會(huì)現(xiàn)調(diào)用基類的對(duì)應(yīng)方法，這里調(diào)用不到，所以防止了被拷貝構(gòu)造和賦值。6：對(duì)象語義還可以通過智能指針的方式來做，例如再使用STL的時(shí)候，STL必須支持拷貝，釋放時(shí)機(jī)變得不同，通過計(jì)數(shù)的方式來決定。
代碼：
Node.h------------------------------------------------------------------------------------------------
#ifndef _NODE_H_#define _NODE_H_#include <cfloat>#include <iostream>namespace PoEdu{	class NonCopyable//對(duì)象語義是拿來限制的不產(chǎn)生拷貝。對(duì)象語義還可以用智能指針的方式來實(shí)現(xiàn)。STL的時(shí)候	{	protected:		NonCopyable(){}	private: 		NonCopyable(const NonCopyable&){ std::cout << "NonCopyable(NonCopyable&)" << std::endl; }		const NonCopyable& operator=(const NonCopyable&) = delete;//等于刪除，不寫=delete也可以，方便程序閱讀。	};	class Node:public NonCopyable//對(duì)象語義的實(shí)現(xiàn)。	{	public:		Node(){}		virtual ~Node(){}		virtual double Calc() const = 0;	};	class NumberNode :public Node	{	public:		NumberNode(const double number) :num_(number){}		double Calc() const override//override告訴程序員這個(gè)方法是重寫的		{			return num_;		}	private:		double num_;	};	class BinaryNode :public Node	{	public:		BinaryNode(Node* left, Node* right) :left_(left), right_(right)		{		}		~BinaryNode()		{			delete left_;			delete right_;			std::cout << "delete_lr" << std::endl;		}	protected:		Node* left_;//父類指針可以指向子類對(duì)象。		Node* right_;	};	class AddNode :public BinaryNode	{	public:		AddNode(Node* left, Node* right) :BinaryNode(left, right)		{		}		double Calc() const override		{			return left_->Calc() + right_->Calc();		}	};	class SubNode :public BinaryNode	{	public:		SubNode(Node* left, Node*right) :BinaryNode(left, right)		{		}		double Calc() const override		{			return left_->Calc() - right_->Calc();		}	};	class MulitplyNode :public BinaryNode	{	public:		MulitplyNode(Node* left, Node*right) :BinaryNode(left, right)		{		}		double Calc() const override		{			return left_->Calc() * right_->Calc();		}	};	class DivideNode :public BinaryNode	{	public:		DivideNode(Node* left, Node*right) :BinaryNode(left, right)		{		}		double Calc() const override		{			double divisor = right_->Calc();			if (divisor > DBL_EPSILON || divisor < -DBL_EPSILON)			{				divisor = left_->Calc() / right_->Calc();			}			return divisor;		}	};	class UnaryNode :public Node	{	public:		UnaryNode(Node* child) :child_(child){}		~UnaryNode()		{			delete child_;			std::cout << "delete_c" << std::endl;		}	protected:		Node* child_;	};	class MinusNode :UnaryNode	{		MinusNode(Node *child) :UnaryNode(child)		{		}		double Calc() const override		{			return -child_->Calc();		}	};}#endifmain.c-------------------------------------------------------------------------------------------------
#include <iostream>#include "Node.h"int main(){	using namespace PoEdu;	Node *p = new NumberNode(10);	Node *p1 = new NumberNode(20);	Node *p2 = new NumberNode(30);	Node *calc = new AddNode(p, new MulitplyNode(p1, p2));	std::cout << calc->Calc() << std::endl;	return 0;}