Path: utzoo!attcan!uunet!husc6!psuvax1!rutgers!columbia!garfield!fox
From: fox@garfield (David Fox)
Newsgroups: comp.lang.c++
Subject: Re: Friend specifier considered harmful
Message-ID: <5870@columbia.edu>
Date: 7 Sep 88 04:10:42 GMT
References: <61@cybaswan.UUCP> <1988Sep2.174327.6439@ateng.uucp>
Sender: news@columbia.edu
Reply-To: fox@garfield.UUCP (David Fox)
Organization: Columbia University CS Department
Lines: 15

In article <1988Sep2.174327.6439@ateng.uucp> chip@ateng.UUCP (Chip Salzenberg) writes:
>I used "friend" once where it proved very useful: an implementation of a
>hash table.
>
>The HashTable class contains an array of pointers to HashNode.  Each
>HashNode contains a pointer to the next HashNode.  I made HashTable a friend
>of HashNode.  This allowed easy access to the HashNode "next" pointer but
>_only_ for HashTable member functions.

Yes, this is an example of `friend' creating *more* type security rather than
less.  The HashNode class need have *no* public members whatsoever, so that
the class itself effectively becomes a private `member' of the HashTable
class.

-David Fox