The function checkCashRegister(price, cash, cid) simulates a real cash register.

It takes:

• price → cost of the item
• cash → amount given by the customer
• cid → cash-in-drawer (array showing how much of each denomination is in the drawer)

And returns:

• Whether the drawer is OPEN, CLOSED, or has INSUFFICIENT_FUNDS,
• Along with how much change to return (and in which denominations).

Hello, I would like to contribute this cash register program to the repository. It uses a greedy algorithm to handle cash transactions and determine change accurately. Please let me know if I can submit a pull request for review.