木头

#include <iostream>
using namespace std;
 
template<typename T>
class Singleton
{
protected:
	static T* m_psSingleton;
 
public:
	Singleton()
	{
		m_psSingleton = static_cast<t  *>(this);
	}
 
	virtual ~Singleton()
	{
		m_psSingleton = NULL;
	}
 
	static T& GetSingleton(){ return *m_psSingleton; }
	static T* GetSingletonPtr(){ return m_psSingleton; }
};
 
class System : public Singleton<system>
{
public:
	void Print()
	{
		cout << " System " << endl;
	}
};
template<> System* Singleton<system>::m_psSingleton  = NULL;
 
 
void main()
{
	System* pSystem = System::GetSingletonPtr();
	pSystem->Print();
}

#include <iostream>
using namespace std;
 
template<typename T> class Display
{
public:
	void Print()
	{
		cout << ((T*)this)->m_nData << endl;
	}
};
 
struct Object : public Display
{ 
	friend class Display; 
public: 
	Object( int nData ) : m_nData ( nData ){} 
private: 
	int m_nData; 
}; 
void main() 
{ 
	Object cObj(100); 
	cObj.Print(); 
}