From: Li Chen <chen_li3@...>
Date: 2009-02-11T10:32:27+09:00
Subject: Re: how to do the recursion

William James wrote:

>> If you found Pascal's code somewhat puzzling, let me explain.
> His customary language is CLisp, so when he deigns to dabble
> in Ruby, he tries to make his code look lispish.


Hi Will,

Thank you for your rubyish code.

Yes. I am really confused when I read Pascal's codes. I don't think 
nowhere in Pixaxe ever mentions about function BUT only methods and 
objects!

I have questions about two code lines:
1) result <<

What does it mean, concatenate nothing???

2) num.odd?
When I run the code Ruby complains about #odd?. I check the class Fixnum 
and I can't find #odd? So I change it to num%2==1 and Ruby runs happily.


Thanks,

Li


> 
> def dec_to_binary num, result = []
>   result <<
>     if num.odd?
>       1
>     else
>       0
>     end
>   if num < 2
>     result.reverse.join ""
>   else
>     dec_to_binary num/2, result
>   end
> end
> 
> 
> p dec_to_binary 254

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