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From: asrap@warwick.ac.uk (Sean Legassick)
Newsgroups: comp.lang.c
Subject: Re: Nasty bug
Message-ID: <1990Aug31.115751.8649@warwick.ac.uk>
Date: 31 Aug 90 11:57:51 GMT
References: <0093BF08.7F3834E0@rigel.efd.lth.se> <11473@crdgw1.crd.ge.com>
Sender: news@warwick.ac.uk (Network news)
Organization: University of Warwick, UK
Lines: 38

In article <11473@crdgw1.crd.ge.com> volpe@underdog.crd.ge.com (Christopher R Volpe) writes:
=In article <0093BF08.7F3834E0@rigel.efd.lth.se>, e89hse@rigel.efd.lth.se
=writes:
=|>Later I rewrote
=|>prnval() as:
=|>
=|>prnval(s,f)
=|>char *s;
=|>double f;
=|>{
=|>   if(f == 0.0)
=|>       sscanf(s,"%lf",&f);
=|>   printf("%10.2f\n",f);
=|>}
=
=This is the correct solution anyway.

	There is still a possible problem though. Comparing floating-point
values to 0 like that can cause problems, especially if the values been
put through the mangle of promotion etc. Its far less likely to cause problems
if you use something like :
	if (f < 0.005)

	As the orginal poster did not describe the nature of the problem when
the program was run (or compiled) this could have been the cause.
=|>
=|> Henrik Sandell
=                                          
===================
=Chris Volpe
=G.E. Corporate R&D
=volpecr@crd.ge.com

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Sean Legassick,       cuuee@uk.ac.warwick.cu  "Improbability factor of one
Computing Services    asrap@uk.ac.warwick.cu    to one. We have normality.
University of Warwick      	 	         Anything you still can't
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