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 purchase therefore ,the maximum change is 5 bath.-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 purchase　 therefore ,the maximum change is 5 bath.