Re^4: Why is Zero not 0?

I checked out another node referenced in the post replies about -0.00. Oh my!!!! This is just getting to me. Integer math or not. Philosophically or mathematically I understand where you're coming from ... but logically it doesn't make sense. By having negative zero what you have is that the following statement is not truly factual

if($x==0){print "I'm ZERO!\n");

$x could come in as -0.00 or -9.049848394839e-14. We now have problems if your referring to say dollars and cents. I hear what you are saying ... I guess it is what it is.:o(

Comment on Re^4: Why is Zero not 0?

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Re^5: Why is Zero not 0? by Joost (Canon) on Feb 07, 2008 at 01:30 UTC
$x could come in as -0.00 or -9.049848394839e-14. But you don't WANT -9.049848394839e-14 to be exactly equal to 0. And that goes for any comparison between floats, which is why you need to specify your tolerance. `sub comp { my ($x,$y,$delta) = @_; $x -$delta >= $y && $x + $delta <= $y; }` [download] "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]
Re^6: Why is Zero not 0? by lodin (Hermit) on Feb 07, 2008 at 02:18 UTC
Did you get the `+` and `-` swapped? Now `comp(5, 4.5, 1)` is false and `comp(5, 4.5, -1)` is true. Personally I prefer to use the good old standard mathematical way of expressing it: `if (abs($x - $y) <= $tolerance) { print "$x and $y are 'equal'"; }` [download] lodin	[reply] [d/l] [select]
Re^7: Why is Zero not 0? by Joost (Canon) on Feb 07, 2008 at 11:50 UTC
I must have been sleeping when I posted that. I swear it was wrong when I posted it and then I immediately "corrected" it :) "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]
Re^5: Why is Zero not 0? by zentara (Cardinal) on Feb 05, 2008 at 11:10 UTC
*$x could come in as -0.00 or -9.049848394839e-14.* It reminds me of the attempt to detect the soul, by weighing bodies before and after death. What a mess that concept is. :-) I'm not really a human, but I play one on earth. Cogito ergo sum a bum	[reply]