haskell我的最后一行“;putStr";抛出错误
我的最后一行使编译器抛出错误。有什么问题吗?2个问题:haskell我的最后一行“;putStr";抛出错误,haskell,Haskell,我的最后一行使编译器抛出错误。有什么问题吗?2个问题: 缩进对您的if语句不利 您没有将2个操作链接起来(参见下面的示例) 您的代码已修复: import Data.List import Data.Char isIn :: (Eq a) => [a] -> [a] -> Bool needle `isIn` haystack = any (needle `isPrefixOf` ) (tails haystack) encode :: Int -> Strin
- 缩进对您的if语句不利
- 您没有将2个操作链接起来(参见下面的示例)
import Data.List
import Data.Char
isIn :: (Eq a) => [a] -> [a] -> Bool
needle `isIn` haystack = any (needle `isPrefixOf` ) (tails haystack)
encode :: Int -> String -> String
encode offset msg = map (\c -> chr $ ord c + offset) msg
main :: IO()
main =
if "arts" `isIn` "artsisgood" then
putStrLn "is in"
else
putStrLn "not in"
putStr (encode 3 "hey")
2个问题:
- 缩进对您的if语句不利
- 您没有将2个操作链接起来(参见下面的示例)
import Data.List
import Data.Char
isIn :: (Eq a) => [a] -> [a] -> Bool
needle `isIn` haystack = any (needle `isPrefixOf` ) (tails haystack)
encode :: Int -> String -> String
encode offset msg = map (\c -> chr $ ord c + offset) msg
main :: IO()
main =
if "arts" `isIn` "artsisgood" then
putStrLn "is in"
else
putStrLn "not in"
putStr (encode 3 "hey")
从缩进的角度看,似乎您正在尝试使用
do
符号进行编写。只需添加关键字do
即可修复代码:
import Data.List
import Data.Char
isIn :: (Eq a) => [a] -> [a] -> Bool
needle `isIn` haystack = any (needle `isPrefixOf` ) (tails haystack)
encode :: Int -> String -> String
encode offset = map (\c -> chr $ ord c + offset)
-- encode offset msg = map (\c -> chr $ ord c + offset) msg
main :: IO()
main = do
if "arts" `isIn` "artsisgood"
then putStrLn "is in"
else putStrLn "not in"
putStr (encode 3 "hey")
main2 =
if "arts" `isIn` "artsisgood"
then putStrLn "is in"
else putStrLn "not in"
>> putStr (encode 3 "hey")
从缩进的角度看,似乎您正在尝试使用
do
符号进行编写。只需添加关键字do
即可修复代码:
import Data.List
import Data.Char
isIn :: (Eq a) => [a] -> [a] -> Bool
needle `isIn` haystack = any (needle `isPrefixOf` ) (tails haystack)
encode :: Int -> String -> String
encode offset = map (\c -> chr $ ord c + offset)
-- encode offset msg = map (\c -> chr $ ord c + offset) msg
main :: IO()
main = do
if "arts" `isIn` "artsisgood"
then putStrLn "is in"
else putStrLn "not in"
putStr (encode 3 "hey")
main2 =
if "arts" `isIn` "artsisgood"
then putStrLn "is in"
else putStrLn "not in"
>> putStr (encode 3 "hey")
如果你遇到错误/你可能害怕/但不要匆忙/请复制并粘贴(你的错误)。如果你遇到错误/你可能害怕/但不要匆忙/请复制并粘贴(你的错误)。