C++ COM编程之什么是接口？

/*
** FileName     : SimpleInterfaceDemo
** Author       : Jelly Young
** Date         : 2013/12/11
** Description  : More information, please go to https://www.jb51.net
*/
#include <iostream>
#include <combaseapi.h>
using namespace std;
interface IExample1
{
     virtual void __stdcall Fx1() = 0;
     virtual void __stdcall Fx2() = 0;
};
interface IExample2
{
     virtual void __stdcall Fy1() = 0;
     virtual void __stdcall Fy2() = 0;
};
// Implementation
class CImplementation : public IExample1, public IExample2
{
public:
     // Implementation IExample1
     void __stdcall Fx1() { cout<<"CImplementation::Fx1"<<endl; }
     void __stdcall Fx2() { cout<<"CImplementation::Fx2"<<endl; }
     // Implementation IExample2
     void __stdcall Fy1() { cout<<"CImplementation::Fy1"<<endl; }
     void __stdcall Fy2() { cout<<"CImplementation::Fy2"<<endl; }
};
// Client
int main()
{
     cout<<"Create an instance of the component."<<endl;
     CImplementation *pCImplementation = new CImplementation;
     // Get the IExample1 pointer
     IExample1 *pIExample1 = pCImplementation;
     // Use the IExample1 interface
     pIExample1->Fx1();
     pIExample1->Fx2();
     // Get the IExample2 pointer
     IExample2 *pIExample2 = pCImplementation;
     // Use the IExample2 pointer
     // Use the IExample2 interface
     pIExample2->Fy1();
     pIExample2->Fy2();
     // Destroy the component
     if (pCImplementation != NULL)
     {
          delete pCImplementation;
          pCImplementation = NULL;
          pIExample1 = NULL;
          pIExample2 = NULL;
     }
}

#define __STRUCT__ struct
#define interface __STRUCT__