how to use MFC to realize the function instead of C

[Igor Vartanov]

1. You need to build/format a string prior to outputting it with MessageBox:

CString msg;
msg.Format(_T("Camera USB driver version : %s\n"), instr.version_cam_driver); // pretty much the same :)
AfxMessageBox(msg);

2. Considering how WFS_RevisionQuery() is used in main() I suppose you can call it immediately. But don't forget to include the corresponding lib file into your project.