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From: "Frank J. Lhota" <NOSPAM.FrankLho@rcn.com>
Newsgroups: comp.lang.ada
Subject: Re: float problem
Date: Sun, 7 Jul 2002 10:08:01 -0400
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Date: 2002-07-07T14:07:52+00:00
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The problem is that 0.1 cannot be represented exactly as a floating point
number. When you add 5 copies of 0.1 to 1.0, the error in the representation
of 0.1 is multiplied by 5. The error is small enough to not affect the
printed output, where things are rounded to six significant digits, but it
does result in a value of f that is slightly more than -0.5. You can confirm
this by adding the following statement right before the statement where f
gets incremented by 0.1:

    if f > -0.5 then
        Put_Line ( "f > -0.5, that's the problem!" );
    end if;