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Re: IE and IEE 754

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From "Christoph M. Becker" <cmbecker69@arcor.de>
Newsgroups comp.lang.javascript
Subject Re: IE and IEE 754
Date Wed, 27 Aug 2014 22:35:04 +0200
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Evertjan. wrote:

> RobG <rgqld@iinet.net.au> wrote on 27 aug 2014 in comp.lang.javascript:
> 
>> In most browsers:
>>    0.57 + 8.36 + 3.36 + 0.19 = 12.479999999999999
>> in IE it returns:
>>    12.479999999999998
>> Is IE wrong, or is the above difference allowable within IEEE 754?
> 
> Both are and must be wrong in the sense that the binary converions
> of floting point fractional decimal values NEVER can be right.

Wrong.  Consider e.g. 0 or 2.

> So why use a standard that defines how wrong they must be?

To be able to quantify the inaccuracy.

> Just remember every time,
> that you should not compare such values without prior rounding.

AFAIK it is common to compare for equality with

    Math.abs(a - b) < epsilon

See also Number.EPSILON[1].

> If you are a sticker for correctness and these are monitary values,
> like $ or €, use integer cent values in variables, and write decimals with 
> string manupulation.

Are you suggesting that storing $123.45 as 12345 is better than storing
it as 123.45?  As ECMAScript implementations typically have no integer
type, there is no difference regarding the precision of further
calculations.

[1]
<http://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.epsilon>

-- 
Christoph M. Becker

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Thread

IE and IEE 754 RobG <rgqld@iinet.net.au> - 2014-08-27 22:44 +1000
  Re: IE and IEEE 754 John Harris <niam@jghnorth.org.uk.invalid> - 2014-08-27 15:23 +0100
  IE and IEEE 754 (was: IE and IEE 754) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-08-27 20:59 +0200
  Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-27 22:04 +0200
    Re: IE and IEE 754 "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-27 22:35 +0200
      Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 00:07 +0200
        Re: IE and IEE 754 "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-28 00:47 +0200
          Re: IE and IEE 754 Gene Wirchenko <genew@telus.net> - 2014-08-28 10:13 -0700
            Re: IE and IEE 754 "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-28 22:15 +0200
              Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 23:24 +0200
                Re: IE and IEE 754 "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-29 01:16 +0200
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-29 09:32 +0200
      Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-27 23:59 +0100
        Re: IE and IEE 754 "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-28 02:55 +0200
          Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 09:50 +0200
            Re: IE and IEE 754 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-08-28 12:21 +0200
              Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 13:42 +0200
          Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-28 11:27 +0100
            Re: IE and IEE 754 Gene Wirchenko <genew@telus.net> - 2014-08-28 10:16 -0700
              Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-29 00:04 +0100
                Re: IE and IEE 754 Gene Wirchenko <genew@telus.net> - 2014-08-29 11:15 -0700
                IEEE 754 (was: IE and IEE 754) "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-29 21:30 +0200
                Re: IEEE 754 (was: IE and IEE 754) Gene Wirchenko <genew@telus.net> - 2014-09-02 11:22 -0700
                Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-29 20:42 +0100
                IEEE 754 (was: IE and IEE 754) "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-29 23:29 +0200
                Re: IEEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-29 23:27 +0100
                Re: IE and IEE 754 Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-08-30 20:32 +0100
                Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-31 01:04 +0100
                IE and IEEE 754 Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-09-01 23:05 +0100
    Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-28 00:05 +0100
      Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 08:56 +0200
        Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 09:51 +0200
          Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-28 11:16 +0100
            Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-28 13:34 +0200
              Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-28 23:41 +0100
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-29 09:09 +0200
                Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-29 12:39 +0100
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-29 16:55 +0200
                Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-29 18:28 +0100
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-30 00:37 +0200
                Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-29 23:53 +0100
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-30 01:08 +0200
                Re: IE and IEE 754 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-08-30 00:40 +0100
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-30 09:32 +0200
                Re: IE and IEE 754 Gene Wirchenko <genew@telus.net> - 2014-08-29 11:22 -0700
                Re: IE and IEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-30 00:14 +0200
  IE and IEEE 754 (was: IE and IEE 754) "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-08-27 22:08 +0200
    Re: IE and IEEE 754 RobG <rgqld@iinet.net.au> - 2014-08-28 22:50 +1000
    Re: IE and IEEE 754 RobG <rgqld@iinet.net.au> - 2014-08-28 22:55 +1000
    Re: IE and IEEE 754 (was: IE and IEE 754) Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-08-28 21:50 +0100
      Re: IE and IEEE 754 (was: IE and IEE 754) "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-29 09:43 +0200
        Re: IE and IEEE 754 (was: IE and IEE 754) Denis McMahon <denismfmcmahon@gmail.com> - 2014-08-29 08:42 +0000
        Re: IE and IEEE 754 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-08-30 16:24 +0200
          Re: IE and IEEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-30 17:08 +0200
            Re: IE and IEEE 754 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-08-30 18:12 +0200
              Re: IE and IEEE 754 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-08-30 18:32 +0200

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