gistfile1.rb

def rotx(x, string, encrypt=true)
  i = 0
  alpha = 'abcdefghijklmnopqrstuvwxyz'
  newStr = ''

  alpha.reverse! unless encrypt
 
  # convert to one cycle
  x = x > 26 ? x % 26 : x
  
  while i < string.length  do
    char = string[i]
    isCap = (char =~ /[A-Z]/) == 0
    lower = char.downcase
    position = alpha.index(lower)

    i +=1

    if position.nil?
      newStr += char
      next
    end

    # will loop to start
    if position + x > alpha.length
      letter = alpha[x - (alpha.length - position)]
    # will remain within limit
    else
      letter = alpha[position + x]
    end

    # check capitaliztion
    newStr += isCap ? letter.upcase : letter
  end
  
  puts newStr
end