Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!iuvax!bsu-cs!dhesi
From: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Newsgroups: comp.lang.c
Subject: Re: hardcoded constants
Message-ID: <5226@bsu-cs.UUCP>
Date: 17 Dec 88 15:24:59 GMT
References: <1988Dec8.173158.11839@utzoo.uucp> <846@starfish.Convergent.COM> <33604@think.UUCP> <2478@ficc.uu.net>
Reply-To: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Organization: CS Dept, Ball St U, Muncie, Indiana
Lines: 36

In article <2478@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>How about sizeof "/"? Or does that return sizeof(char *)?

I considered this and rejected it because it is misleading.  We need 2
because one is for a '/' in the middle and one is for a trailing null,
not because we need two for just '/'.  That "/" is a string and needs
two is not really the point, even though it gives the right answer.

The format I prefer most is actually:

     strlen(a) + 1 + strlen(b) + 1

because it arranges the components of the expression in the right
order.  (It also avoids the magic number 2.  However, 1 is a magic
number here even though it isn't usually considered to be one.)  It
would be nice to be able to say

     strlen(a) + sizeof('/') + strlen(b) + 1

but unfortunately sizeof('/') is the same as sizeof(int).

One could also do

     #define   ONE_CHAR   1
     #define   TWO_CHARS  2

and then say things like:

     strlen(a) + ONE_CHR + strlen(b) + ONE_CHR
     strlen(a) + strlen(b) + TWO_CHARS

This sounds like the type of error undergraduates make when they are
first asked to use symbolic constants, but upon thinking I realize that
it could actually clarify the code quite a bit.
-- 
Rahul Dhesi         UUCP:  <backbones>!{iuvax,pur-ee}!bsu-cs!dhesi