Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!uflorida!usfvax2!pollock
From: pollock@usfvax2.EDU (Wayne Pollock)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Float to integer conversion problem in LSC 3.0?
Keywords: Lightspeed, LSC, conversion
Message-ID: <1120@usfvax2.EDU>
Date: 22 Aug 88 17:38:15 GMT
References: <5813@batcomputer.tn.cornell.edu> <4933@teddy.UUCP>
Reply-To: pollock@usfvax2.usf.edu.UUCP (Wayne Pollock)
Organization: University of South Florida at Tampa
Lines: 27

In article <5813@batcomputer.tn.cornell.edu> (Julian Vrieslander) writes:
>
>        double d;
>        long m,n;
>	
>        m = 126.0;          /* m becomes 126 */	
>        d = 12.6 * 10.0;    /* d becomes 126 */
>        n = d;              /* n becomes 125 !! */
>		
>I cannot understand why n gets "rounded down" to 125.

This is just a result of floating point roundoff error.  To
make things work right when assigning a float or double to an int or
long, always add a small amount like this:

		n = d + 0.00001;

if you want to truncate accurately, or use:

		n = d + 0.5;

or some library routine if you want to round the number.  Assuming the
default conversions will always work perfectly is just asking for
trouble.

Wayne Pollock (The MAD Scientist)	pollock@usfvax2.usf.edu
Usenet:		...!{uflorida, codas}!usfvax2!pollock
GEnie:		W.POLLOCK