access_control_1.rb

class Account
  def initialize(balance)
    @balance = balance
  end

  def transfer_money(to,amount)
    p "Sender now has #{balance - amount}"
    p "Recipient now has #{to.balance + amount}"
  end
  
protected
  def balance
    @balance
  end
end

chris = Account.new(100)
osama = Account.new(150)

chris.transfer_money(osama, 25)