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Re^6: Problem with a sort result: weird subtraction behaviour?

by kzwix (Sexton)
on Jan 27, 2016 at 14:32 UTC ( [id://1153749]=note: print w/replies, xml ) Need Help??


in reply to Re^5: Problem with a sort result: weird subtraction behaviour?
in thread Problem with a sort result

Discipulus, rdfield, you are both correct: This is a problem with long integers.

What I don't understand is: Why are the integers correctly remembered, correctly displayed, but incorrectly compared to 0 ? Because, let's face it, it's the core of the problem:

When it's a "small" number, it is correctly evaluated as positive, negative, or null.

When it is a "big" number, then there may be problems in evaluating the sign. Much like if some bit from the big number was used as a sign bit, or whatever, where the real good practice would merely be to check the sign at the start of the number string...

I mean, if it starts with a "+" or a digit, then it's positive. If it starts with a "-", it's negative. We keep that "sign", unless all digits are 0 -> in which case it is merely null.

Did I miss something, there ?

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Re^7: Problem with a sort result: weird subtraction behaviour?
by choroba (Cardinal) on Jan 27, 2016 at 18:47 UTC
    The problem is that the code that implements the behaviour is in C. There's no number string, there are different integer types with different byte sizes. 
    ($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

    [download]
[reply]
[d/l]

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