星期日, 8月 17, 2008

如何用Haskell寫出笨拙的99乘法表

目前想法如下。

mult_line x = map (x*) [1..9]
mult_table x = map mult_line [1..x]

之後,我在ghci中呼叫
*Main> mult_table 9
[[1,2,3,4,5,6,7,8,9],[2,4,6,8,10,12,14,16,18],[3,6,9,12,15,18,21,24,27],[4,8,12,16,20,24,28,32,36],[5,10,15,20,25,30,35,40,45],[6,12,18,24,30,36,42,48,54],[7,14,21,28,35,42,49,56,63],[8,16,24,32,40,48,56,64,72],[9,18,27,36,45,54,63,72,81]]