Let us design a control unit for a simple coin-operated candy machine. Candy costs 20 bath ,and the machine accept 5 bath and 10 bath. Change should be return if less than 5 bath is deposited. No more than 25 bath can be deposited on a single purchas

一个简单的自动售货机控制器，投足25美分便发糖果，并且自动找零-A simple vending machine controller, 25 cents will be made every move she makes candy and give change automatically