The following is a virtual vending machine simulator that meets the following requirements:

$1.$The customer can input the following coins: $5-$cent, $10-$cent, $25-$cent.

$2.$ When $75$ cents is input, the machine will activate the dispenserand permit the customer to select a product.

$3.$When at least $75$ cents is input no more coins will be accepted.

$4.$ Change will be returned to the customer if more than $75$ cents is deposited.

$5.$ A reset button will return the customer$$s money.

$6.$ When a product is dispensed, $75$ cents will be added to the machine$$s $$Total Money Collected$$ register.

$7.$No product is dispensed if less than $75$ cents is deposited.

$8.$ The current number of items available for each product is stored

in a counter.

$9.$ When a service technician restocks the machine the item count

for each product is set to $15,$which is the maximum number of

items that can be stocked.

$10.$ If the number of products available is zero for any one product

the machine will light a $$sold out$$ light and no action will betaken if that product is selected.

This circuit uses only combinational logic and is an example of a reasonably complex system.

Unfortunatley, there are two issues with the machine that I$\text{'}$m dealing with.

$1.$ When a product is dispensed, the coins deposited and change returned is not reset back to zero. This means that a customer could deposit $75$ cents and then keep selecting products untilthe machine is empty.

$2.$ Requirement six says that the machine totals all of the money col$-$

lected but that is not functional.

How do I go about fixing this?