Question

Shapes2D

Write the following four classes to practice using an abstract class and polymorphism. Submit all four classes.

Shape2D class

For this class, include just an abstract method name get2DArea() that returns a double.

Rectangle2D class

Make this class inherit from the Shape2D class. Have it store a length and a width as fields. Provide a constructor that takes two double arguments and uses them to set the fields. Note, the area of a rectangle is the length times the width.

Circle2D class

Also make this class inherit from the Shape2D class. Have it store a radius as a field. Provide a constructor that takes a double argument and uses it to set the field. Note, the area of a circle is PI times it's radius times it's radius.

Shape2DDriver class

Have this class provide a method named displayName() that takes an object from just any of the above three classes (you can't use an Object type parameter). Have the method display the area of the object, rounded to one decimal place.

Answer 1

Hello There,

Please find the answer mentioned Below

/*
 * Construction of Abstract class Shape2D
 * */
public abstract class Shape2D {

        abstract double get2DArea();
}

/*
 * Construction of class Rectangle2D with length and breadth as field
 * */
public class Rectangle2D extends Shape2D{
        private double length;
        private double breadth;

        public Rectangle2D(double length, double breadth) {
                super();
                this.length = length;
                this.breadth = breadth;
        }

        @Override
        double get2DArea() {

                return length*breadth;
        }

}
/*
 * Construction of class Circle with radius as field
 * */
public class Circle2D extends Shape2D {
        
        double radius;
        


        public Circle2D(double radius) {
                super();
                this.radius = radius;
        }



        

        @Override
        double get2DArea() {
                // TODO Auto-generated method stub
                return 3.14*(radius*radius);
        }

}


import java.text.DecimalFormat;
import java.util.Scanner;
/*
 * Construction of final class Shape2D which will take the input from user ,
 * format the area to one pointer than print the area
 * */

public class Shape2DDriver {

        public static void main(String[] args) {
                Scanner scan_obj=new Scanner(System.in);
                System.out.println("Enter the length in double");
                double length=scan_obj.nextDouble();
                System.out.println("Enter the breadth in double");
                double breadth=scan_obj.nextDouble();
                System.out.println("Enter the radius in double");
                double radius=scan_obj.nextDouble();
                Shape2D rectangle_obj= new Rectangle2D(length,breadth);
                Shape2D circle_obj=new Circle2D(radius);
                double rectangle_area=print(rectangle_obj.get2DArea());
                System.out.println("area of rectangle\n"+rectangle_area);
                double circle_area=print(circle_obj.get2DArea());
                System.out.println("area of circle\n"+circle_area);
        }

        private static double print(double get2dArea) {
                String formatted_value = new DecimalFormat("#.#").format(get2dArea);
                double area=Double.parseDouble(formatted_value);
                return area;

        }

}

Output:

Thank You!!