在Haskell中分類時輸入錯誤

Question

我想在Haskell中編寫一個函數來整數。這是我的代碼：

div :: Int -> Int -> Double 
div a b =a/b 

然而，當我嘗試complie它，我總是得到錯誤：

baby.hs:20:10: 
    Couldn't match expected type ‘Double’ with actual type ‘Int’ 
    In the first argument of ‘(/)’, namely ‘a’ 
    In the expression: a/b 

baby.hs:20:12: 
    Couldn't match expected type ‘Double’ with actual type ‘Int’ 
    In the second argument of ‘(/)’, namely ‘b’ 
    In the expression: a/b 
Failed, modules loaded: none. 

Answer 1

您需要的Int S使用realToFrac先轉換，例如。重命名div到myDiv避免與前奏的衝突，節目

myDiv :: Int -> Int -> Double 
myDiv a b = realToFrac a/realToFrac b 

main = putStrLn $ show $ myDiv 5 2 

輸出

2.5