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From: andy@research.canon.oz.au (Andy Newman)
Newsgroups: comp.lang.c
Subject: Re: towards a faster isdigit()
Message-ID: <1991May9.025552.2292@research.canon.oz.au>
Date: 9 May 91 02:55:52 GMT
References: <1991May8.030515.7004@twinsun.com> <716@taumet.com>
Sender: andy@research.canon.oz.au (Andy Newman)
Reply-To: andy@research.canon.oz.au (Andy Newman)
Organization: Canon Information Systems Research Australia
Lines: 12

eggert@twinsun.com (Paul Eggert) writes:
> Why not use the following implementation instead?
>
>	#define isdigit(c) ((unsigned)((c)-'0') < 10)

Only works for character sets that have the decimal digits
arranged contiguously and with digit '0' having a lower
numeric value than any other digit character. This works
for ASCII and EBCDIC but what about other character sets?
-- 
Andy Newman (andy@research.canon.oz.au) Canon Info. Systems Research Australia
	"If education were illegal would more people would try it?"