factorial_test.rb

require 'rubygems'
require 'inline'

class MyTestInC
  inline do |builder|
    builder.c <<-EOF
      long factorial(int max) {
        int i=max, result=1;
        while (i >= 2) {
          result *= i--;
        }
        return result;
      }
    EOF
  end
end

class MyTestInRuby
  def factorial(n)
    return 1 if n == 0
    n * factorial(n-1)
  end
end


def time_test(test_name, times=10000, &block)
  start = Time.now
  if block_given?
    times.times { yield }
    puts "Called block '#{test_name}' #{times} times in #{Time.now - start} seconds"
  end
end

c = MyTestInC.new
r = MyTestInRuby.new

time_test "With C Extension" do
  c.factorial(10)
end

time_test "In Pure Ruby" do
  r.factorial(10)
end