function rev(str::String)
  words = split(str, " ")
  len = length(words)
  i = 1
  j = len

  while i < len/2
    tmp = words[j]
    words[j] = words[i]
    words[i] = tmp
    i += 1
    j -= 1
  end

  for word in words
    str *= word * " "
  end
  return str
end