Re^5: Why is Zero not 0?

$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;
}
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"What should it profit a man, if he should win a flame war, yet lose his cool?"

Comment on Re^5: Why is Zero not 0? Download Code

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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]