[Haskell-cafe] Little errors in number calculations

[Abby Henríquez Tejera]

Hi.

I've seen that in GHC sometimes there are little errors in some basic
number calculations:

*Prelude> 123.35503 * 10.0
1233.5502999999999

*Prelude> properFraction 123.35503
(123,0.3550299999999993)

whereas in Hugs no such errors seem to occur (that I have found, at
least):

*Hugs> 123.35503 * 10.0
1233.5503

(but:)

*Hugs> properFraction 123.35503
(123,0.355029999999999)

I understand that error may (and will) happen in floating point, but
it surprises me that they do so easily, and, above all, the difference
between GHC and Hugs. Does someone know why does this difference
occur?

(Thanks in advance, by the way :) ).