虚函数 ，接口，到底有什么用呢？

以前我都是在C++ 里面写C，只用到 简单的C++面对对象知识

 

 

#include
     
      class IServerLogic{
      virtual ~IServerLogic(){}public:  virtual bool OnStart()=0;  virtual bool OnStop()=0;};class ServerLogic:public IServerLogic{public:  virtual bool OnStart(){printf("OnStart\n");return true;};  virtual bool OnStop(){printf("OnStop\n");return true;};};class ServerFactory{public:  static ServerLogic* Create(){
   return new ServerLogic();}};int main(){  IServerLogic *iserverlogic=ServerFactory::Create();  iserverlogic->OnStart();  iserverlogic->OnStop();    delete iserverlogic;        return 0;}