Assignment 19 Deadline: Nov pm COSC211 CRN15376 Session 15 (Nov. 7)

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Reynard Banks
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This in-class assignment has 3 points in total. Every bug costs 0.1-0.3 based on its severity. The deadline for this assignment is Thursday, Nov. 8, NOON, 12 pm.

1 This in-class assignment has 3 points in total. Every bug costs based on its severity. The deadline for this assignment is Thursday, Nov. 8, NOON, 12 pm. Note: Make sure your console output is exactly the same as the output in this instruction. Otherwise, you may get 0.1 point off. Overall goal: in this assignment, you practice using interfaces and inner classes. Step 1. Create a Java project and create a Main class and a main method. (similar steps in: (1.0) Step 2. Create an Interface: Ordered We used this interface in the previous assignment. Now, we are going to create one ourselves to reinforce our memory about interfaces. If you don t know how to create an interface, check out the following slides: Page 2 for Eclipse, Page 3 for BlueJ. The name of the interface is Ordered. It should have two method headings: precedes and follows. In the end, the interface should look like the following snapshot. (1.0) Step 3. Create a class: OrderedHourlyEmployee In this step, please create a class, OrderedHourlyEmployee, that implements the interface, Ordered. So the class declaration looks like the following snapshot. This class should have the following instance variables: 1. private String name 2. private Date hiredate 3. private double wagerate 4. private double hours 1

2 This class should also have a constructor that has four input parameters: 1. String thename 2. Date thedate 3. double thewage 4. double thehours. The constructor s heading should look like the following snapshot. To use the type Date, you need to import java.util.date; in the beginning of the java file. If thewagerate is negative, or thehours is negative, or thename is null, or thedate is null, use System.exit(1) to exit the program. Otherwise, initialize the instance variables with the corresponding parameter values. Then, because class OrderedHourlyEmployee implements Ordered, so we need to add two methods that are specified in the interface, Ordered. For precedes, if the input object, other, is null or is not an instance of OrderedHourlyEmployee, return false. Otherwise, check if thewage of this employee is smaller than thewage of the other employee. If yes, return true, else return false. For follows, if the input object, other, is null or is not an instance of OrderedHourlyEmployee, return false. Otherwise, check if thewage of this employee precedes thewage of the other employee. If yes, return false; else return true. Finally, add a getter (accessor) method for the private instance variable: name. This method should return the name of this employee. Step 4. Test in main To test your OrderedHourlyEmployee, add the following code in the main method in the Main class. 2

3 Run the above main method, and the output should be: Now we are going to practice inner classes! In the following steps, we are going to create our first classic data structure: List. In general, a list can store any type of data, but in this assignment, our list is going to store a list of int values. (0.5) Step 5. Create a class, List Inside the class List, create an inner class, ListNode. The inner class, ListNode, has two instance variables: 1. private int val 2. private ListNode next Create a constructor for ListNode, so that the constructor has one input parameter, int theval. Inside the constructor, initialize this.val with theval, and this.next with null. Then, let s define the outer class, List. 3

4 List has one instance variable: private ListNode head head should be initialized with null. (0.5) Step 6. Implement the constructor of List Add a constructor of List, so that the constructor has one input parameter: int[] arr The constructor s heading should look like the following snapshot. Finally, add the following override tostring method to List. Step 7. Test Add three lines of code in main method, highlight as follows. Run the main method, and the output should look like the following snapshot. 4

5 *************Final Step: Submission If you don t define packages in your project, click upload files and place your java files (not a folder, nor.class files, nor any other files other than.java) there. This rule is for me to grade your assignment more easily Thanks! And commit. <End> 5

9/17/2018 Programming Data Structures. Encapsulation and Inheritance

9/17/2018 Programming Data Structures Encapsulation and Inheritance 1 Encapsulation private instance variables Exercise: 1. Create a new project in your IDE 2. Download: Employee.java, HourlyEmployee.java