Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!ucsd!ames!pacbell!att!cbnewsc!nevin1
From: nevin1@cbnewsc.ATT.COM (nevin.j.liber)
Newsgroups: comp.lang.c++
Subject: Re: information hiding
Message-ID: <1421@cbnewsc.ATT.COM>
Date: 26 Jun 89 04:23:43 GMT
References: <6031@watdcsu.waterloo.edu> <6590164@hplsla.HP.COM>
Reply-To: nevin1@ihlpb.ATT.COM (nevin.j.liber)
Organization: AT&T Bell Laboratories
Lines: 21

In article <6590164@hplsla.HP.COM> jima@hplsla.HP.COM (Jim Adcock) writes:
|Someone else wrote:
|> Ultimately, I would like to give them a library containing my classes and
|> NOTHING else.

|Why?  Seems like letting people see a little bit of your class might be a 
|good thing.  I find it very comforting to be able to look at complex.h for
|example.  Reading it, I get the impression that the person writing it might
|very well know what they're doing.  Yet not enough is given away that I 
|could /cause/get into/ any trouble.

Maybe, maybe not.  Programmers are clever people :-); they tend to use
ALL the information they are given.  From the header file one might
guess on how the class is implemented, find some undocumented side
effects, and write code that uses these side effects.  This breaks the
clean interface which classes provide, and leads to many of the
"existing practice" problems which can be found throughout pANS C.  I'd
much rather have all the implementation details for a class hidden from
me.
-- 
NEVIN ":-)" LIBER  AT&T Bell Laboratories  nevin1@ihlpb.ATT.COM  (312) 979-4751