bob.rb

class Bob
  def respond_to(input)
    @input = input.strip

    return "Fine. Be that way!" if silence?
    return "Whoa, chill out!"   if shouting?
    return "Sure."              if question?
    "Whatever."
  end

  def silence?
    @input.empty?
  end

  def shouting?
    @input == @input.upcase && @input != @input.downcase
  end

  def question?
    @input.end_with?("?")
  end
end