Question

Go to the Java API and review the Rectangle class briefly. As directed below, create a subclass of the Rectangle class called BetterRectangle as described below. Create another class called RectangleTester, which fully tests the BetterRectangle, by displaying a menu that allows a user to process data for multiple rectangles until they choose to quit. Be sure to include sample runs as block comments in your tester source code file.

P9.10 The Rectangle class of the standard Java library does not supply a method to compute the area or perimeter of a rectangle. Provide a subclass BetterRectangle of the Rectangle class that has getPerimeter and getArea methods. Do not add any instance variables. In the constructor, call the setLocation and setSize methods of the Rectangle class. Provide a program that tests the methods that you supplied.

​P9.11 Repeat excersize P9.10, but in the BetterRectangle constructor, invoke the super class constuctor.

Use Dia to create a UML class diagram for BetterRectangle, being sure to show the parent class and relationship to Rectangle (do not need variables/methods for this class).

Answer 1

Please find my implementation.

import java.awt.Rectangle;

public class BetterRectangle extends Rectangle {

  

   // constructor

   public BetterRectangle(int x, int y, int width, int height){

      

       // calling setLocation

       setLocation(x, y);

      

       // calling setSize

       setSize(width, height);

   }

  

   // method to return perimeter

   public double getPerimeter(){

       return 2*(getHeight() + getWidth());

   }

  

   // function to return area

   public double getArea(){

       return getHeight()*getWidth();

   }

  

   // main method

   public static void main(String[] args) {

      

       // Creating two objects of type BetterRectangle

       BetterRectangle r1 = new BetterRectangle(3, 4, 6, 7);

      

       BetterRectangle r2 = new BetterRectangle(5, 6, 12, 15);

      

       System.out.println("R1: Area: "+r1.getArea()+", Perimeter: "+r1.getPerimeter());

       System.out.println("R2: Area: "+r2.getArea()+", Perimeter: "+r2.getPerimeter());

   }

}

/*

Sample Run:

R1: Area: 42.0, Perimeter: 26.0

R2: Area: 180.0, Perimeter: 54.0

*/