StallManager

1.The stall manager uses the system to (1) add and edit customers, (2) process and keep track of payments, and (3) manage rewards. (For simplicity, we assume that the manager is the only person working at the stall and using the system.)

2.A customer in the system is characterized by the following information:

First name

Last name

Zip code

Email address

3.All payments must be performed using a credit card. No cash payments are allowed.

4.A credit card scanner attached to the system allows the system to read, when a card is swiped, (1) the cardholder’s name, (2) the card’s account number, (3) the card's expiration date, and (4) the card's security code.

5.Similarly, the system's hardware is capable to connect with a payment-processing service provider that can process credit card transactions.

6.Every time a customer spends $100 or more in a single purchase, he or she gets a $10 discount towards a future purchase as a reward. The discount does not expire and is cumulative.

7.The system should send an email to a customer when he or she gets a reward.

8.Customers who spend $1000 or more in a calendar year achieve "gold" status, which entitles them to a 5% discount for life and on every purchase. The change of status is effective immediately after reaching the specified threshold. The 5% discount is applied before any other discount.

9.The system should send an email to a customer when he or she achieves "gold" status.

10.At any particular  point in time, the stall manager should be able to display, for any customer in the system, a list of their purchases. For each purchase, the stall manager should be able to see (1) date, (2) amount, and (3) whether discounts were applied (and which ones).