Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!iuvax!bsu-cs!dhesi
From: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Newsgroups: comp.lang.c
Subject: Re: hardcoded constants
Message-ID: <5146@bsu-cs.UUCP>
Date: 14 Dec 88 16:51:28 GMT
References: <1988Dec8.173158.11839@utzoo.uucp> <846@starfish.Convergent.COM> <9134@smoke.BRL.MIL> <1988Dec13.172306.16195@utzoo.uucp>
Reply-To: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Organization: CS Dept, Ball St U, Muncie, Indiana
Lines: 27

In article <1988Dec13.172306.16195@utzoo.uucp> henry@utzoo.uucp (Henry
Spencer) writes:
>The policy we try to follow is that if you must hard-code a constant,
>then it must be accompanied by a comment explaining why that particular
>number is there.

A suggestion:  If you want to hard-code a constant, use a #define
anyway:

     check_break() {
     #define   CTRL_C    3        /* ASCII control C */
        if (keyscan() == CTRL_C)
           ...
     }

A well-chosen name will make the code understandable.  Any additional
information about the hard-coded value can be in a comment to the
#define itself.  Scanning the source for all #defines will let you
locate all hard-coded constants with some confidence.

So I find the above code fragment preferable to the following:

     check_break() {
        if (keyscan() == 3)       /* check for ASCII control C */
           ...
     }
-- 
Rahul Dhesi         UUCP:  <backbones>!{iuvax,pur-ee}!bsu-cs!dhesi