From: Robert Klemme <bob.news@...>
Date: 2003-08-07T17:05:03+09:00
Subject: Re: Ruby Query


<srijit@yahoo.com> schrieb im Newsbeitrag
news:221d8dbe.0308062037.2a5558f2@posting.google.com...
> Ruby is a nice and expressive language. Now my favourite Ruby site is
> http://whytheluckystiff.net/articles/2003/08/04/rubyOneEightOh
>
> I have a query about Ruby
> 1) Like Python can I increase the maximum depth of Ruby Interpreter
> Stack? This will help to calculate factorial(1000) recursively.
> Without increasing the recursion limit, it will not possible to
> calculate factorial(1000) recursively with Ruby 1.8 (Win 98). It is
> possible to do the same with Python.

Hmmm...  Calculating factorial recursively is really inefficient and after
all, Ruby is not a functional language although it has some features of
them

def fact1(n)
  n == 1 ? 1 : n*fact1(n-1)
end

def fact2(n)
  f = 1

  for i in 1..n
    f *= i
  end

  f
end

require 'benchmark'
include Benchmark

N=700

bm do |x|
  x.report("recursive") do
    for n in 1..N
      fact1 n
    end
  end

  x.report("iterative") do
    for n in 1..N
      fact2 n
    end
  end
end

08:01:55 [ruby]: ruby fact.rb
      user     system      total        real
recursive  4.891000   0.015000   4.906000 (  4.922000)
iterative  2.906000   0.000000   2.906000 (  2.906000)
08:02:13 [ruby]:

Cheers

    robert