C++ Problem (Advanced)

    
void * ptr = MakeClass("BClass");
    

          
//This should be used outside of any functions preferably in the

// same file (note there will need to be a slight difference 

//between the class name and the string for this to work (for

// example remove the C from the front of it

#define REGISTER_CLASS(classname,stringname) __declspec(dllexport) void* stringname(){void *c = new classname; return c;
}

typedef void *(*GET_CLASS)();

void *CreateClass(LPSTR Name)
{
//There should be a variable hInstance (containing the instance of the program you are running now)

GET_CLASS *Function = (GET_CLASS*)GetProcAddress(hInstance,Name);
if(Function == NULL)
{
return NULL;
//error

}
void *rv = Function();
return rv;
}

//example

class CClass
{
public:
void hello() {};
};

//then in a .cpp file

REGISTER_CLASS(CCLass,Class)

//to create this class you would call

something = CreateClass("Class");

          

  template<class T>
struct CreateObject{
   string name;
   CreateObject(string newname):name(newname){}
   T *Create(){return new T;}
};

template<class T>
void Factory::RegisterClass(string name){
   ObjectCreatorList.push_back(CreateObject<T>(name));
}  

    
#include "stdafx.h"
#include <map>

class BaseFactory
{
public:
	BaseFactory()
	{
		m_mapDb.insert(std::pair<char*, BaseFactory*>("BaseFactory", this));
	}

	static void *CreateInstance(char *pClassName)
	{
		std::map<char*, BaseFactory*>::iterator it = m_mapDb.find(pClassName);
		BaseFactory *pFact = it->second;
		if(pFact == NULL)
			return NULL;

		return pFact->CreateNew();
	}

protected:
	virtual void *CreateNew()
	{
		return NULL;
	}

	static std::map<char *, BaseFactory *> m_mapDb;
};
std::map<char*, BaseFactory*> BaseFactory::m_mapDb = std::map<char*, BaseFactory*>();
BaseFactory _Factory;

#define DEFINE_FACTORY( c )
	class c##Factory : public BaseFactory	{	public:		c##Factory()		{			m_mapDb.insert(std::pair<char*, BaseFactory*>(#c, this));		}	protected:		void *CreateNew()		{			return new c();		}	};	c##Factory _Factory##c;

#define CREATE_INSTANCE( c )(c##*)BaseFactory::CreateInstance(#c);


class a
{
public:
	void PrintType()
	{
		printf("a\n");
	}
};
DEFINE_FACTORY(a);

class b
{
public:
	void PrintType()
	{
		printf("b\n");
	}
};
DEFINE_FACTORY(b);

int _tmain(int argc, _TCHAR* argv[])
{
	a *pA = (a *)BaseFactory::CreateInstance("a");
	void *pV = BaseFactory::CreateInstance("b");

	pA->PrintType();
	((b*)pV)->PrintType();
	return 0;
}