> Does Haskell specify how div and mod should behave when
> given one or both arguments negative?
>
> Eg, in hugs we get:
>
> div 1 3 = 0
> div (-1) 3 = -1
> div 1 (-3) = -1
> div (-1) (-3) = 0
>
> and so on.
We usually describe div as the version of division that "truncates
towards negative infinity". What this actually means is that when there
are two solutions to
a `divMod` b = (d,m)
such that d*b + m == a
and abs m < b
div picks the one where d is the closest to minus infinity, and quot
picks the one where d is closer to zero.
eg. (-1) `divMod` 3 = (-1, 2) or (0, -1)
divMod gives you (-1,2), whereas quotRem gives you (0,-1).
Hope this helps.
Cheers,
SImon
_______________________________________________
Haskell mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/haskell
