I'm learning Haskell and I would like to have user input x numbers into the console and store those numbers in array which can be passed on to my functions.
Unfortunately no matter what I try it doesn't work, here is my code:
-- Int Array
intArray :: Int -> IO [Int]
intArray 0 = []
intArray x = do
str <- getLine
nextInt <- intArray (x - 1)
let int = read str :: Int
return int:nextInt
-- Main Function
main = do
array <- intArray 5
putStrLn (show array)
You need an IO [Int] in your base case:
intArray 0 = return []
and you need to change the return in your recursive case to use the correct precedence:
return (int:nextInt)
As an aside, [Int] is a singly-linked list of ints, not an array. You could also simplify your function using replicateM from Control.Monad:
import Control.Monad
intArray i = replicateM i (fmap read getLine)
Data.Array
fmap read getLine is otherwise known as readLn, except that the latter will give any parse errors immediately rather than when the value is used later.
readLn is okay, but you need to catch an exception to deal with parse errors. The (non-standard) readMaybe and readEither seem a bit more Haskell-flavored.