From: Christopher Dicely <cmdicely@...>
Date: 2009-04-01T08:05:13+09:00
Subject: Re: Why does mathn kill this method?

On Tue, Mar 31, 2009 at 3:46 PM, Siep Korteling <s.korteling@gmail.com> wrote:
> Really stumped here.
>
> def sum_digits(n)
>    sum = 0
>    while n>0
>       sum += n % 10
>       n /= 10
>       end
>    sum
>  end
>
> STDOUT.sync=true
>
> puts sum_digits(12) #=> 3
>
> require 'mathn'
> puts sum_digits(12) # hangs
>
>
> What am I doing wrong?

This should illustrate the problem:

irb(main):001:0> require 'mathn'
=> true
irb(main):002:0> n = 10
=> 10
irb(main):003:0> n /= 10
=> 1
irb(main):004:0> n /= 10
=> 1/10
irb(main):005:0> n /= 10
=> 1/100

The solution:

def sum_digits(n)
  sum = 0
  while n>0
    sum += n % 10
    n = n.div 10
    end
  sum
end