[Haskell-cafe] recursion problem part 2
Roelof Wobben
r.wobben at home.nl
Fri Feb 6 16:07:41 UTC 2015
Jerzy Karczmarczuk schreef op 6-2-2015 om 16:57:
>
> Le 06/02/2015 16:48, Roelof Wobben a écrit :
>> Im only sure that somehow I take the wrong turn somewhere because I
>> cannot figure out why I do not get the right answer.
>>
>> I think I have the value of n wrong.
> Did you read my answer entirely? Do so, find the red fat line
>
> You take n=1, and you write: n<10 not True.
> You don't need to be a specialist on recursion, to see the error.
>
> Jerzy
>
oke,
Another try :
toDigits :: Integer -> [Integer]
toDigits n
| n < 0 = []
| n < 10 = [n]
| otherwise = toDigits (n `div` 10) ++ [n `mod` 10]
isDigits 1
n < 0 not true.
n < 10 true so [1]
IsDigits 12
n < 0 not true
n < 10 not true
toDigits 1 + [2]
toDigits 1 + [2]
n < 0 not true
n < 10 true [1] ++ [2]
1 ++2 = [1,2]
I think I understand it finnaly.
Roelof
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