Path: utzoo!utgpu!watserv1!watmath!att!cbnewsj!veenu
From: veenu@cbnewsj.ATT.COM (veenu.r.rashid)
Newsgroups: comp.lang.c
Subject: Re^2: Help with function
Keywords: abs(), strtod(), don't work
Message-ID: <3477@cbnewsj.ATT.COM>
Date: 18 Jan 90 20:27:08 GMT
References: <2385@ektools.UUCP>
Reply-To: veenu@cbnewsj.ATT.COM (veenu.r.rashid,mt,)
Distribution: na
Organization: AT&T Bell Laboratories
Lines: 38

In article <2385@ektools.UUCP> randolph@ektools.UUCP (Gary L. Randolph) writes:
>In article <3198@cbnewsj.ATT.COM> veenu@cbnewsj.ATT.COM (veenu.r.rashid) writes:
>>	On the compiler I'm using, abs() and strtol() seem to generate incorrect
>>or at least inaccurate results.  I'm using the following code:
>>main(int argc, char *argv[])
>>{
>>	double temp;
>>
>>	temp = strtod(argv[1]);		/* get the argument as a double	*/
>>	printf("Absolute value of %g is %g\n", temp, abs(temp));
>>}
>>Any code, suggestions, comments greatly appreciated.
>

Well, I got quite a flurry of messages about the problem above which I
posted to the net..  The vast majority of the messages pointed out one
obvious flaw:  the usage of strtod() takes two args.  This is quite right.
I used atof(), which takes one argument, in the actual program, but
posted strtod(), since I typed in the message on the fly.  I apologize
for the confusion, but the other part of the responses did help in a
major way -- using fabs().  As it turns out, the abs() macro definition
tends to return int, (but not always!), while fabs() returns the correct
floating point value.  Now, is this just a macro characteristic or is it
the compiler I'm using.  (*Disclaimer*  The question is academic in my
case!)

Thanks very much to all who replied to the original posting :-)



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