def cesaer_cipher string, shift_number
  alphabet_lower = %w[a b c d e f g h i j k l m n o p q r s t u v w x y z]
  phrase_array =  string.chars
  final_encode = []

  shifted_alphabet = alphabet_lower[-shift_number..-1]
  0.upto(alphabet_lower.length - shift_number -1) do |index|
     shifted_alphabet << alphabet_lower[index]
  end

  0.upto(phrase_array.size - 1) do |letter|
     0.upto(alphabet_lower.size - 1)  do |symbol|
        if phrase_array[letter] == alphabet_lower[symbol]
            final_encode.push(shifted_alphabet[symbol])
            break
        elsif phrase_array[letter] == alphabet_lower[symbol].capitalize
            final_encode.push(shifted_alphabet[symbol].capitalize)
            break
        else
            final_encode.push(phrase_array[symbol])
            break
        end
      end
  end
  return  final_encode
end

cipher = cesaer_cipher 'I am going to', 3
puts cipher