如何在haskell中输入整数? (在控制台中输入) [英] How to input an integer in haskell? (input in console)
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问题描述
如何在控制台中输入整数,将其存储在变量中,然后将其作为我创建的函数的参数传递?
How can I enter an integer in the console, store it in a variable and then pass it as a parameter of a function that I have created?
到目前为止所以我必须这样做:
So far so that it works I had to do as follows:
在最后一行你可以看到我是如何应用这个功能的,我想做的就是要求控制台的变量作为整数应用于函数,然后打印结果。
In the last line you can see how I have been applying the function, what I want to do is to ask for the variables by console to be applied as integers to the function and then print the result.
mayor :: Int -> Int -> Double
mayor x y =
if x < y
then 0.1
else 0.3
compra :: Int -> Int -> Int -> Int -> Int -> Int -> Double
compra n v u iva p vp =
let valor_compra = (fromIntegral v) * (fromIntegral n) * (1 - mayor n u)
valor_iva = valor_compra * (fromIntegral iva) / 100
valor_puntos = fromIntegral (p * vp)
efectivo = if (valor_puntos < valor_compra) then valor_compra-valor_puntos else 0
in valor_iva + efectivo
main = do
print (compra 20 2000 7 14 10 1500)
我这样做的方式给了我一个结果
16920.0
The way I do it gives me as a result 16920.0
推荐答案
使用 getLine
或 readLn
然后将输入值解析为您需要的类型:
Use getLine
or readLn
and then parse the input value to the type you need it to be like so :
mayor :: Int -> Int -> Double
mayor x y =
if x < y
then 0.1
else 0.3
compra :: Int -> Int -> Int -> Int -> Int -> Int -> Double
compra n v u iva p vp =
let valor_compra = (fromIntegral v) * (fromIntegral n) * (1 - mayor n u)
valor_iva = valor_compra * (fromIntegral iva) / 100
valor_puntos = fromIntegral (p * vp)
efectivo = if (valor_puntos < valor_compra) then valor_compra-valor_puntos else 0
in valor_iva + efectivo
main = do
putStrLn "enter value for x: "
input1 <- getLine
putStrLn "enter value for y: "
input2 <- getLine
let x = (read input1 :: Int)
let y = (read input2 :: Int)
print (compra x y 7 14 10 1500)
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