gistfile1.txt

require 'reward/starbucks'
require 'reward/united'
 
class Card
  def initialize(params)
    @type     = params[:type]
    @username = params[:username]
    @password = params[:password]
  end
 
  def my_klass
    @klass ||= Object.const_get(@type.capitalize) if Object.const_defined?(@type.capitalize)
  end
 
  def reward_balance
    my_klass.try(:card_balance, @username, @password)
  end
end