Re: [Haskell-cafe] Why 'round' does not just round numbers ?

On Mon, 27 Oct 2008, L.Guo wrote:

I think this is unresonable. then try it in GHC 6.8.3.

Prelude> round 3.5 4 Prelude> round 2.5 2

Is there any explanation about that ?

It's the definition we learnt in school ... I think one reason is that repeated rounding should not be worse than rounding in one go. Consider the rule 'use ceiling when the first removed digit is 5'. Then 0.45 - (round to one place) -> 0.5 - (round to integer) -> 1 but 0.45 - (round to integer) -> 0 This is avoided by the school definition.