ABC Supermarket is implementing a POS system to automate transactions at cash registers. The POS system will track sales and differentiate transactions by payment type - cash, credit card, or gift certificate. Customers will select products, cashiers will scan items and compute the total, and customers will select a payment method for the cashier to process.

1. ABC Supermarket System
ABC Supermarket is a small chain of supermarkets that needs to be
automated. Here is the process of how the system is envisioned to
work for ABC.
1. ABC Supermarket will be using a POS(Point of Sales) System. This
will primarily be installed in the cashiers to keep track of different
sales transactions.
2. The transactions are differentiated by the type of payment that is
used by the customer. A customer can pay using Cash, Credit Card ,
or Gift Certificate.
3. The user will collect all the products he/she wants to buy, he/she
then brings them to the cashier.
4. The Cashier lady will complete the transaction by encoding the the
product code, price and quantity for every product selected by the
customer.
5. After the total amount is computed, the customer is asked about the
type of payment he/she will make.
6. If the user pays in cash, the cashier lady will encode the amount
given by the customer and the change given to the customer. If a
Credit Card is used, the cashier lady will encode the card number ,
card company name, and the approval number that is received from
the bank. Finally , if a Gift Certificate is used, the name of the owner
of the GF and the GF number is encoded.
Create the class diagram for the given system.