动态创建类的对象

#include <iostream>
#include<string>

using namespace std;
class CObject;

///类信息表结构
struct CRuntimeClass
{
	char* m_lpszClassname ; //类名
	CObject* (_stdcall *m_pfnCreateObject)(); ///对象构建函数指针
	CObject* _stdcall CreateObject();			///对象构建函数的声明
};

//CObject类声明及实现
class CObject
{
public :
	virtual void SayHello() {cout<<"Hello CObject \n";}
};

///派生类Myclass及实现

class Myclass : public CObject
{
public:
	virtual void SayHello() {cout<<"Hello Myclass\n";}

public:
	///对象动态创建的声明
	static CRuntimeClass classMyclass;		//定义CRuntimeClass变量作为信息表
	static CRuntimeClass *GetRuntimeClass();//获得信息表指针的函数
};

///动态创建的实现
///对象构建函数的实现
CObject* _stdcall CreateObject()
{
	return new Myclass;
}

///填写信息表
CRuntimeClass Myclass::classMyclass = {"Myclass" , CreateObject};

///获得类信息表指针函数的实现
CRuntimeClass * Myclass::GetRuntimeClass()
{
	return &Myclass::classMyclass ;
}

///主函数
void main()
{
	char _lpszCLS[10];
	cout<<"请输入类名：     ";
	cin>>_lpszCLS;

	CRuntimeClass * p = Myclass::GetRuntimeClass ();

	if(!strcmp(p->m_lpszClassname , _lpszCLS))
	{
		CObject* _stdcall pp = p->m_pfnCreateObject();
		pp->SayHello ();
	}
	else
	{
		cout<<"NO"<<endl;
	}
}