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Groups > comp.lang.java.programmer > #35833
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|---|---|
| From | Arne Vajhøj <arne@vajhoej.dk> |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: double == double |
| Date | Wed, 19 Oct 2016 21:16:57 -0400 |
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| Lines | 46 |
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| References | <double-20161012130409@ram.dialup.fu-berlin.de> <nu7quv$aur$1@dont-email.me> <nu7sl4$h0a$1@dont-email.me> <nu7vq8$qnj$3@jstuckle.eternal-september.org> <nu80cv$un8$1@dont-email.me> <nu8m9u$i6g$1@jstuckle.eternal-september.org> <nu8uce$chj$1@dont-email.me> |
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On 10/19/2016 7:08 PM, Jake Jarvis wrote:
> Am 19.10.2016 um 22:50 schrieb Jerry Stuckle:
>> On 10/19/2016 10:36 AM, Jake Jarvis wrote:
>>> Am 19.10.2016 um 16:26 schrieb Jerry Stuckle:
>>>> On 10/19/2016 9:32 AM, Eric Sosman wrote:
>>>>> On 10/19/2016 9:03 AM, Mike Amling wrote:
>>>>>> If a==0.0 and b==0.0, there's no need to test whether either is -0.0.
>>>>>> The function could be simplified to
>>>>>>
>>>>>> public static double max(final double a, final double b) {
>>>>>> return a==0.0 && b==0.0 ? 0.0 : (a>=b ? a : b);
>>>>>> }
>>>>>
>>>>> This would return +0.0 for max(-0.0, -0.0).
>>>>>
>>>>
>>>> PMJI, but how do you figure? a==0.0 && b==0.0 would be false
>>>
>>> No.
>>>
>>
>> And why not? -0.0 != 0.0.
>>
>
> But exactly that is not the case
>
> https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1
>
> | 15.21.1. Numerical Equality Operators == and !=
> | [...]
> | Floating-point equality testing is performed in accordance with the
> rules of the IEEE 754 standard:
> | [...]
> | Positive zero and negative zero are considered equal.
And just for completeness.
IEEE 754 2008 section 5.11 says:
<quote>
Comparisons shall ignore the sign of zero (so +0 = −0).
</quote>
Arne
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Re: double == double Mike Amling <mamling@chaff.us> - 2016-10-19 08:03 -0500
Re: double == double Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-10-19 09:32 -0400
Re: double == double Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-19 10:26 -0400
Re: double == double Jake Jarvis <pig_in_shoes@yahoo.com> - 2016-10-19 16:36 +0200
Re: double == double Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-19 16:50 -0400
Re: double == double Jake Jarvis <pig_in_shoes@yahoo.com> - 2016-10-20 01:08 +0200
Re: double == double Arne Vajhøj <arne@vajhoej.dk> - 2016-10-19 21:16 -0400
Re: double == double Arne Vajhøj <arne@vajhoej.dk> - 2016-10-19 21:19 -0400
Re: double == double Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-19 21:47 -0400
Re: double == double Arne Vajhøj <arne@vajhoej.dk> - 2016-10-19 21:52 -0400
Re: double == double Michael Jung <miju@golem.phantasia.org> - 2016-10-19 19:39 +0200
Re: double == double Mike Amling <mamling@chaff.us> - 2016-10-22 07:15 -0500
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