9.9.3. Trio Student Solution 2

The following is a free response question from 2014. It was question 4 on the exam. You can see all the free response questions from past exams at https://apstudents.collegeboard.org/courses/ap-computer-science-a/free-response-questions-by-year.

Question 4. The menu at a lunch counter includes a variety of sandwiches, salads, and drinks. The menu also allows a customer to create a “trio,” which consists of three menu items: a sandwich, a salad, and a drink. The price of the trio is the sum of the two highest-priced menu items in the trio; one item with the lowest price is free. Each menu item has a name and a price. The four types of menu items are represented by the four classes Sandwich, Salad, Drink, and Trio. All four classes implement the following MenuItem interface.

public interface MenuItem
{
  /** @return the name of the menu item */
  String getName();

  /** @return the price of the menu item */
  double getPrice();
}

The following diagram shows the relationship between the MenuItem interface and the Sandwich, Salad, Drink, and Trio classes.

../_images/trioUML.png

Figure 1: UML class diagram showing MenuItem is implemented by Sandwich, Salad, Drink, and Trio.

For example, assume that the menu includes the following items. The objects listed under each heading are instances of the class indicated by the heading.

../_images/menuItemObjs.png

Figure 2: Example objects

The menu allows customers to create Trio menu items, each of which includes a sandwich, a salad, and a drink. The name of the Trio consists of the names of the sandwich, salad, and drink, in that order, each separated by “/” and followed by a space and then “Trio”. The price of the Trio is the sum of the two highest-priced items in the Trio; one item with the lowest price is free. A trio consisting of a cheeseburger, spinach salad, and an orange soda would have the name "Cheeseburger/Spinach Salad/Orange Soda Trio" and a price of $4.00 (the two highest prices are $2.75 and $1.25). Similarly, a trio consisting of a club sandwich, coleslaw, and a cappuccino would have the name "Club Sandwich/Coleslaw/Cappuccino Trio" and a price of $6.25 (the two highest prices are $2.75 and $3.50).

9.9.3.1. Grading Rubric

Below is the grading rubric for the Trio class problem.

../_images/TrioGrading.png

Figure 3: The grading rubric for the Trio class problem.

9.9.3.2. Practice Grading

The following is the second sample student response.

../_images/TrioStudentSol2a.png

Figure 4: The start of the second sample student response to the Trio class problem.

../_images/TrioStudentSol2b.png

Figure 5: The end of the second sample student response to the Trio class problem.

Apply the grading rubric shown above as you answer the following questions.

Apply the Grading Rubric

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