设计模式-----Singleton模式

Singleton模式比较简单可以用以下UML图表示: 

                                             

                                             Singleton模式

//Singleton模式

#include <iostream>

using namespace  std;

 

class SingleTon

{

public:

         static SingleTon* Instance();

private:

         SingleTon();

         static SingleTon *  _instance;

};

 

SingleTon* SingleTon::_instance=NULL;

 

SingleTon::SingleTon()

{

         cout<<"Create SingleTon Object"<<endl;

}

 

SingleTon* SingleTon::Instance()

{

         if (_instance==NULL)

         {

                   return new SingleTon();

         }

         else

         {

        return _instance;

         }

}

 

int main(void)

{

         SingleTon *obj1 =SingleTon::Instance();

        

         return 0;

}