                                     (* Chapter 16 - Program 4 *)
unit Person;

interface

type
   Person_ID = object
      Name : string[30];
      Salary : integer;
      constructor Init;
      procedure Display; virtual;
   end;

implementation

   constructor Person_ID.Init;
   begin
   end;

   procedure Person_ID.Display;
   begin
      WriteLn('Error - this procedure should never be called.');
   end;

end.