CODEWITHSUNDEEP
haskellioint
user2150839
user2150839

Reputation: 483

Haskell: IO confusion with Ints

Hey so I am trying to learn haskell and im running into trouble writing a program that requires me to collect Ints from the user in the terminal. how would i do this ive tried things like this

import Data.Char (digitToInt)


getArguments :: IO Int
getArguments =
    do putStrLn "Enter the number of arguments you want to have"
       arguments <- getChar
       return (digitToInt arguments)


main :: IO()
main = do
    putStrLn "Welcome to Random Argument Generator"
    let x = getArguments
    print x+1

but this does not work plz help!

Upvotes: 1

Views: 106

Answers (1)

cdscfveq
cdscfveq

Reputation: 61

replace let x = getArguments with x <- getArguments

the type signature for getArguments is (correctly) :: IO Int, which means that Int is 'wrapped' inside the IO monad, which means that you have to use the val <- func syntax to unwrap it.

If getArguments were a pure function (:: Int) the let syntax would have been correct.

Upvotes: 6

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