[Haskell-cafe] round function

[Sebastian Sylvan]

On 2/12/06, Chatzianastassiou Achilleas <achatzianastassiou at hotmail.com> wrote:
> Hi all,
>
> I am trying to implement a function that finds the significant figure of a
> number to a specified point i.e. 2.55555 3 = 2.556. I have implemented
> something like:
>
> sig :: (RealFrac a, Integral b) => a -> Int -> a
> sig x y = round y
>
> However this doesn't work. Moreover at the Prelude when i type round 2.3333
> 2 i get an error.
> Any suggestions?
>

Something like:

myround n s = fromIntegral (round (n * factor)) / factor
    where factor = fromIntegral (10^s)

Basically scaling it to bring the specified number of digits to the
left of the decimal point, then rounding, then scaling back.

/S

--
Sebastian Sylvan
+46(0)736-818655
UIN: 44640862