First, I prepared the class blow :
class UserDefinedWindow
{
public:
WNDCLASSEX WindowClass;

DWORD dwExStyle;
LPCTSTR lpClassName;
LPCTSTR lpWindowName;
DWORD dwStyle;

C and C++ are certainly diffrent languages; nobody can deny it.
Whenever, I take some C code, without paying attention if it was C or C++, from this site it doesn't work properly on C++ compiler....