数猜测游戏错误并保持猜测次数 [英] Number guessing game error and keeping count of guesses

问题描述

我在Haskell做了一个数字猜测游戏，我有3个难题。

我做了一个菜单，用户选择什么难度，但是一旦我实现了它，它开始给我一个错误，我可以不知道它是什么。

错误：

  finalename.hs：5：10： 
模式中的解析错误：putStrLn 
可能由缺少'do'引起？ 
  

另外，我将如何执行一个计数，其中计算用户需要多少次猜测？

  import System.Random（randomRIO）
 main :: IO（）
 main = do 
 putStrLn你想玩1）轻松，2）中等或3）硬
 putStrLn通过输入数字1，2或3来选择难度
 choice<  - readLn 
 |选择== 1 =您选择简单>>容易
 |选择== 2 =您选择了媒体>>中等
 |选择== 3 =您选择的很难>>硬
 | otherwiose =您没有选择有效的选择>> main 
 
 easy :: IO（）
 easy = do 
 putStrLn猜测1和13之间的数字：
 rNumber < -  randomRIO（1，10 ）:: IO Int 
 loop rNumber 
 
 medium :: IO（）
 medium = do 
 putStrLn猜测1到25之间的数字：
 rNumber<  -  randomRIO（1,25）:: IO Int 
 loop rNumber 
 
 hard :: IO（）
 hard = do 
 putStrLn猜一猜1到50之间的数字：
 rNumber<  -  randomRIO（1，50）:: IO Int 
 loop rNumber 
 
 loop :: Int  - > IO（）
循环rNumber = do 
 userInput<  -  readLn 
大小写比较rNumber userInput 
 EQ  - > putStrLn正确！ >>主
 LT  - > putStrLn猜测太低，请再试一次>>循环rNumber 
 GT  - > putStrLn猜得太高了，请再试一次>>循环rNumber 
  

解决方案

您需要更改<$ c $

 循环函数可以跟踪猜测的数字和猜测次数： loop :: Int  - > Int  - > IO（）
循环rNumber猜测=做
 putStrLn $你已经做出了++显示猜测++的猜测。 
 ... 
 putStrLn太低，再猜一次
循环rNumber（猜测+ 1）
 ... 
 putStrLn要高，再猜一次
 loop rNumber（gpsses + 1）
  

请注意，当您调用循环递归地通过传递旧猜测计数+1来改变猜测计数。

I am doing a number guessing game in Haskell and I have 3 difficulties.
I made a menu where the user selects what difficulty but once I implemented it, it started giving me an error and I can't figure out what it is.
The error:

finalename.hs:5:10:
Parse error in pattern: putStrLn
Possibly caused by a missing 'do'?

Also how would I go about implementing a count where it counts how many times it takes for the user to guess?

import System.Random (randomRIO)     
main :: IO ()
main = do
     putStrLn "Do you want to play 1) Easy, 2) Medium or 3) Hard"
     putStrLn "Select your difficulty by entering a number 1, 2 or 3"
     choice <- readLn
       | choice == 1 = "You selected easy" >> easy
       | choice == 2 = "You selected medium" >> medium
       | choice == 3 = "You selected hard" >> hard
       | otherwiose = "You did not selected a valid choice" >> main

easy :: IO ()
easy = do
     putStrLn "Guess a number between 1 and 13: "
     rNumber <- randomRIO (1, 10) :: IO Int
     loop rNumber

medium :: IO ()
medium = do
     putStrLn "Guess a number between 1 and 25: "
     rNumber <- randomRIO (1, 25) :: IO Int
     loop rNumber

hard :: IO ()
hard = do
     putStrLn "Guess a number between 1 and 50: "
     rNumber <- randomRIO (1, 50) :: IO Int
     loop rNumber

loop :: Int -> IO ()
loop rNumber = do
       userInput <- readLn 
       case compare rNumber userInput of
         EQ -> putStrLn "Correct!" >> main
         LT -> putStrLn "Guess is too low, try again please" >> loop rNumber
         GT -> putStrLn "Guess is too high, try again please" >> loop rNumber

解决方案

You need to change your loop function to keep track of both the number to guess and the number of guesses:

loop :: Int -> Int -> IO ()
loop rNumber guesses = do
  putStrLn $ "You have made " ++ show guesses ++ " guesses so far."
  ...
  putStrLn "Too low, guess again"
  loop rNumber (guesses+1)
  ...
  putStrLn "To high, guess again"
  loop rNumber (guesses+1)

Note how when you call loop recursively you change the guess count by passing in the old guess count + 1.

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