// Listing 22.2 the PostMasterMessage class

 class PostMasterMessage : public MailMessage
 {
 public:
     PostMasterMessage();
     PostMasterMessage(
         pAddress Sender,
         pAddress Recipient,
         pString Subject,
         pDate creationDate);

     // other constructors here
     // remember to include copy constructor
     // as well as constructor from storage
     // and constructor from wire format
     // Also include constructors from other formats
     ~PostMasterMessage();
     pAddress& GetSender() const;
     void SetSender(pAddress&);
     // other member accessors

     // operator methods here, including operator equals
     // and conversion routines to turn PostMaster messages
     // into messages of other formats.

 private:
     pAddress itsSender;
     pAddress itsRecipient;
     pString  itsSubject;
     pDate itsCreationDate;
     pDate itsLastModDate;
     pDate itsReceiptDate;
     pDate itsFirstReadDate;
     pDate itsLastReadDate;
 };