class AFX_EXT_CLASS CEthernet

{

public:

virtual BOOL Open() = 0;

};


class AFX_EXT_CLASS CTcpServer : public CEthernet

{

public:

virtual BOOL Open() override;

};


class AFX_EXT_CLASS CTcpClient : public CEthernet

{

public:

virtual BOOL Open() override;

};


virtual을 붙이고 ovrride 키워드를 써봤으나 아니되오 ㅠㅠㅠ