find_next_power_of_two.rb

require 'benchmark'

number = 257

def power_of_2?(number)
  return true if number == 1
  return false if number == 0 || number % 2 != 0
  power_of_2?(number / 2)
end

def plus_plus_power_of_2(n)
  while not power_of_2?(n)
    n +=1
  end
  n
end

def next_power_of_2_with_log(n)
  Math.log(n) / Math.log(2) % 1 == 0
  2**((Math.log(n) / Math.log(2)).ceil)
end

if plus_plus_power_of_2(number) == next_power_of_2_with_log(number)
  Benchmark.bmbm(7) do |bm|
    bm.report('plus plus') do
      plus_plus_power_of_2(number)
    end

    bm.report('log') do
      next_power_of_2_with_log(number)
    end
  end
end