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Comparisson operators

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  Comparisson operators jonas.thornvall@gmail.com - 2015-09-28 23:24 -0700
    Re: Comparisson operators "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-09-29 12:16 +0200
    Re: Comparisson operators Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-29 12:24 +0100
      Re: Comparisson operators Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 19:39 +0200
    Re: Comparisson operators Silvio <silvio@internet.com> - 2015-09-30 13:28 +0200

#28754 — Comparisson operators

Does the comparisson operators also suffer from the 32/64 bit integer limit?
What happens if you assign a bigger value will it get truncated?

And what happen if you try to compare elements that is bigger than the scope of javascript integers?

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#28758

jonas.thornvall@gmail.com wrote on 29 Sep 2015 in comp.lang.javascript:

> Does the comparisson operators also suffer from the 32/64 bit integer
> limit? What happens if you assign a bigger value will it get truncated?

Seems simple to test for with your level of experience.

Did you? Results?

Operators feel no pain, maybe you do.
 
> And what happen if you try to compare elements that is bigger than the
> scope of javascript integers? 

What is 'the scope of javascript integers'?

Integers have no scope, they are blind, meseems.

-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#28760

jonas.thornvall@gmail.com writes:

> Does the comparisson operators also suffer from the 32/64 bit integer limit?
> What happens if you assign a bigger value will it get truncated?

You should start by understanding what the type Number is in ECMAScript.
It is not an integer type in the usual sense of the word.  It is a
floating point type with very specific properties usually rather loosely
called "IEEE floating point".  It can, of course, store integer values,
but your reference to a "32/64 bit integer limit" suggests you don't
know what ECMAScript numbers are.

> And what happen if you try to compare elements that is bigger than the
> scope of javascript integers?

A normal floating-point comparison is done, just as it always is.  What
matters is the range of integer values that can be represented exactly.
That range is -(2**53 - 1) to 2**53 - 1.  The latest ECMAScript defines
property, Number.MAX_SAFE_INTEGER with the value 9007199254740991, but
you can always calculate Math.pow(2, 53) - 1.

-- 
Ben.

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#28762

Ben Bacarisse wrote:

> jonas.thornvall@gmail.com writes:
>> And what happen if you try to compare elements that is bigger than the
>> scope of javascript integers?
> 
> A normal floating-point comparison is done, just as it always is.  What
> matters is the range of integer values that can be represented exactly.
> That range is -(2**53 - 1) to 2**53 - 1.  The latest ECMAScript defines
> property, Number.MAX_SAFE_INTEGER with the value 9007199254740991, but
> you can always calculate Math.pow(2, 53) - 1.

This description is so imprecise as to be misleading.  Several integers 
smaller and greater than these boundaries can be stored exactly, but the 
integers *between* the boundaries and the stored integers cannot be, because 
the achievable precision is insufficient.  Insofar Number.MIN_SAFE_INTEGER 
and Number.MAX_SAFE_INTEGER only give the minimum/maximum integer down/up to 
which proper arithmetic is possible (hence “SAFE”).

The minimum/maximum integer than can be represented exactly with IEEE 754 
doubles is approximately ±1.8 × 10³⁰⁸; it is exactly given by
-Number.MAX_VALUE and Number.MAX_VALUE, respectively.  (Note that 
Number.MIN_VALUE gives the smallest floating-point value greater than 0 
instead.)

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

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#28763

On 09/29/2015 08:24 AM, jonas.thornvall@gmail.com wrote:
> Does the comparisson operators also suffer from the 32/64 bit integer limit?
> What happens if you assign a bigger value will it get truncated?
>
> And what happen if you try to compare elements that is bigger than the scope of javascript integers?
>

You keep asking questions that you would not have to ask if you actually 
read the responses you get.

People keep telling you that JavaScript (or ECMAScript if you will) has 
neither 32 nor 64 bit integers and that all numerical values are just 
that, IEEE floating point variables that happen to be able to represent 
a range of whole numbers. Operations on numerical values, including 
comparisons, are performed as IEEE floating point operations.

And before you post any more code: PLEASE LEARN HOW TO USE LOCAL 
VARIABLES OR FORGET ABOUT PROGRAMMING ANYTHING SERIOUS ALTOGETHER!!!

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