[Haskell-cafe] How to decide if a number is an integer?
magicloud.magiclouds at gmail.com
Tue Sep 29 03:13:19 EDT 2009
The properFaction part is correct. So I posted the whole code, since
"isInteger" should accept any reasonable incoming types. Well, in this
one situation, it does not. And I cannot figure out why....
On Tue, Sep 29, 2009 at 3:07 PM, Jimmy Hartzell <jim at shareyourgifts.net> wrote:
> Did you test the properFraction-based code in isolation? If code is
> broken, it's important to figure out which part of it is broken. Also,
> this function is not divided into constituent parts, but is a long unruly
> mess. Dividing it into parts would make it much much more readable, and
> you would then be able to test the parts individually.
>> The original code is
>> givenSum num = map (\a ->
>> let l = (sqrt $ fromIntegral (a * a + 2 + 2 *
>> num)) - (fromIntegral a) in
>> case properFraction l of
>> (_, 0) ->
>> _ ->
>> ) $ take num [1..]
>> :t l is (Floating a) => a
>> Well, in ghci
>> *Main> givenSum 10
>> On Tue, Sep 29, 2009 at 2:45 PM, Thomas DuBuisson
>> <thomas.dubuisson at gmail.com> wrote:
>>> On Mon, Sep 28, 2009 at 11:35 PM, Magicloud Magiclouds
>>> <magicloud.magiclouds at gmail.com> wrote:
>>>> It never matches to (_, 0.0)....
>>>> I mean
>>>> case properFraction l of
>>>> (_, 0) -> l
>>>> _ -> 0 -- always goes here.
>>> Odd, it works fine for me.
>>> f x =
>>> case properFraction x of
>>> (_,0) -> True
>>> _ -> False
>>> *Main> f 5
>>> *Main> f 5.5
>>> *Main> f 4.0
>>> *Main> f 4.00000001
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