大话设计模式C++版——表驱动法改造简单工厂

1、面向接口编程，先改造抽象接口类IOperation

class IOperation
{
public:
	IOperation() : m_nNuml(0), m_nNumr(0) {}
	virtual	~IOperation() {}
	
	virtual	void	SetNum(int nNuml = 0, int nNumr = 0)
	{
		m_nNuml = nNuml;
		m_nNumr = nNumr;
	}

	virtual	int		CalculateResult() = 0;

public:
	typedef	IOperation* (CALLBACK* fn_CreateObject)();

protected:
	int	m_nNuml, m_nNumr;
};

接口基本无改动，由于表驱动法中需要在表中填入驱动函数接口，故先定义一个该接口函数的定义，用于产生具体接口对象。

2、改造接口对象类

class COperation_Add : public IOperation
{
public:
	int		CalculateResult()
	{
		return	m_nNuml + m_nNumr;
	}

	static	IOperation*	CALLBACK CreateObject()
	{
		return	new	COperation_Add();
	}
};


class COperation_Dec : public IOperation
{
public:
	int		CalculateResult()
	{
		return	m_nNuml - m_nNumr;
	}

	static	IOperation*	C