quizz

solution.rb

class UserInfo

  attr_accessor :contact

  def initialize(contact = nil)
    self.contact = contact || NullContact.new
  end

  def contact_name
    contact.name
  end

  def contact_mail
    contact.mail
  end

  def contact_phone
    contact.phone
  end

end

class NullContact

  def name
    "no name"
  end

  def mail
    "no mail"
  end

  def phone
    "no phone"
  end

end

user_info.rb

class UserInfo

  attr_accessor :contact

  def initialize(contact = nil)
    self.contact = contact
  end

  def contact_name
    if contact
      contact.name
    else
      "no name"
    end
  end

  def contact_mail
    if contact
      contact.mail
    else
      "no mail"
    end
  end

  def contact_phone
    if contact
      contact.phone
    else
      "no phone"
    end
  end

end