自己写的练习题(yaht exercise 3.10)

leaveye

今天无聊，翻到了这里，顺手写了一个。

1. module Main where
   
2. 
   
3. import Text.Printf
   
4. import List
   
5. import IO
   
6. 
   
7. getList = do
   
8.   printf "Gime a number (or 0 to stop):\n"
   
9.   n <- getLine >>= return . read
   
10.   if n == 0
    
11.     then return []
    
12.     else getList >>= return . (n:)
    
13. 
    
14. main = do
    
15.     ls <- getList :: IO [Int]
    
16.     printf "sum : %d\n" (sum ls)
    
17.     printf "pruduct : %d\n" (product ls)
    
18.     mapM_ printFac ls
    
19.   where
    
20.     fac x = product [1..x]
    
21.     printFac a = printf "%d! = %d\n" a (fac a)

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PS：默认代码字体居然不等宽，比较不爽。

[ 本帖最后由 leaveye 于 2009-4-14 17:21 编辑 ]