PreferredCustomer Class

A retail store has a preferred customer plan where customers can earn discounts on all their purchases. The amount of a customer’s discount is determined by the amount of the customer’s cumulative purchases in the store as follows:

• When a preferred customer spends $500, he or she gets a 5 percent discount on all future purchases.
• When a preferred customer spends $1,000, he or she gets a 6 percent discount on all future purchases.
• When a preferred customer spends $1,500, he or she gets a 7 percent discount on all future purchases.
• When a preferred customer spends $2,000 or more, he or she gets a 10 percent discount on all future purchases.

Design a class named PreferredCustomer, which extends the Customer class you created in Programming Challenge 7. The PreferredCustomer class should have fields for the amount of the customer’s purchases and the customer’s discount level. Write one or more constructors and the appropriate mutator and accessor methods for the class’s fields. Demonstrate the class in a simple program.