Three Approaches To Reversing A String

reverse.rb

require 'benchmark'

class String
  def swap!(a,b)
    self[a], self[b] = self[b], self[a]
  self
  end
end

string1 = "Pneumonoultramicroscopicsilicovolcanoconiosis"
string2 = "Pneumonoultramicroscopicsilicovolcanoconiosis"
string3 = "Pneumonoultramicroscopicsilicovolcanoconiosis"

def fastest_reverse(string)
  array = string.chars
  new_array = []
  until array.empty? do
    new_array << array.pop
  end
  new_array.join
end

def reverse(string)
  array = string.chars
  new_array = []
  string.size.times do
    new_array << array.pop
  end
  new_array.join
end

def slowest_reverse!(string)
  index1 = 0
  index2 = -1
  (string.size / 2).times do
    string.swap!(index1, index2)
    index1 += 1
    index2 -=1
  end
  string
end

Benchmark.bm do |x|
  x.report { fastest_reverse(string2) }
  x.report { reverse(string3) }
  x.report { slowest_reverse!(string1) }
end