Sign on the professor’s door

Content

int DoorProtocol () KnockSharply(); cc AwaitAnswer (Reply); if (cc ! timeout) if (Reply Enter) return (EnterOffice); else if (Reply Wait) cc AwaitHail (Hail); if (cc timeout) return(ComeBackLater); if (cc DoorOpen I Hail ComeIn) return(EnterOffice); ? else if (Reply Busy) ? DealWithRejection (); ? return (ComeBackLater);