Exercise 4.4 The course information in the registrar's database contains the course number (four digits), the course title, and the number of credits.

• Develop the classes to represent a list of courses.

• Develop the method departmentList, which produces a list of all courses offered in the given department. A department is identified by the first two digits of the course number.

• Develop the method credits, which determines the number of credits student earns in a given course.

Exercise 4.5 The grocery store keeps the inventory as a list of lists of grocery items of different kind (Coffee, IceCream, Juice - see an earlier exercise).

• Develop the classes to represent the inventory for this grocery store.

• Develop the method grossIncome, which computes the gross income from all products in the inventory.

• Develop the method incomeForBrand, which determines the gross income for a given brand of products, given the class name for the products.

• Draw the UML diagram for this collection of classes.