In this lab, you will be implementing the following class hierarchy. Your concre

Question

In this lab, you will be implementing the following class hierarchy. Your concrete classes must call the superclass constructor with the proper number of sides (which is constant for each concrete shape). The perimeter method is implemented in the superclass as it does not change based on the number of sides. The area method must be overridden in each subclass as the area is dependent on the type of polygon. The areas of an equilateral triangle, square, and a regular hexagon given side length a are Ma2, a2, and SyAa2, respectively. The superclass area method should just return 0 as a default value. You are also responsible for writing a small test driver that instantiates each of the concrete subclasses with test values (not necessarily user input), and prints the perimeter and area of each object to the console.

Explanation / Answer

RegularPolygon.java

public class RegularPolygon {
   //Declaring instance variables
   private int numSides;
   private int sideLength;

   /* Parameterized constructor by passing
   * the no of sides and side length as arguments
   */
   public RegularPolygon(int numSides, int sideLength) {
       super();
       this.numSides = numSides;
       this.sideLength = sideLength;
   }

   //Getter methods
   public int getNumSides() {
       return numSides;
   }

   public int getSideLength() {
       return sideLength;
   }

   //Method which calculate the perimeter
   public double perimeter() {
       return getNumSides() * getSideLength();
   }

  
   public double area() {
       return 0;
   }

}

___________________

Triangle.java

public class Triangle extends RegularPolygon {

   //Creating parameterized constructor
   public Triangle(int sideLength) {
       super(3, sideLength);
  
   }

   //This method is used to calculate the area of the triangle
   @Override
   public double area() {
       return (Math.sqrt(3)/4)*getSideLength()*getSideLength();
   }
  

}

_____________________

Square.java

public class Square extends RegularPolygon {

   //Creating parameterized constructor
   public Square( int sideLength) {
       super(4, sideLength);
      
   }
  
   //This method is used to calculate the area of the square
   @Override
   public double area() {
       return getSideLength()*getSideLength();
   }
  

}

___________________

Hexagon.java

public class Hexagon extends RegularPolygon {

   //Creating parameterized constructor
   public Hexagon(int sideLength) {
       super(6, sideLength);

   }
  
   //This method is used to calculate the area of the Hexagon
   @Override
   public double area() {
       return 3*(Math.sqrt(3)/2)*getSideLength()*getSideLength();
   }
  

}

__________________

TestDriver.java

import java.text.DecimalFormat;

public class TestDriver {

   public static void main(String[] args) {
       // DecimalFormat class is used to format the output
       DecimalFormat df = new DecimalFormat("#.##");

       /*
       * Creating the Triangle class object by passing the length of the side
       * as argument
       */
       Triangle t = new Triangle(5);

       // Displaying the area of the equilateral triangle
       System.out.println("The Area of Equilateral Traingle is :" + df.format(t.area()));

       // Displaying the perimeter of the equilateral triangle
       System.out.println("The Perimeter of Equilateral Traingle is :"+ df.format(t.perimeter()));

       /*
       * Creating the Square class object by passing the length of the side as
       * argument
       */
       Square s = new Square(6);
       // Displaying the area of the Square
       System.out.println("The Area of Square is :" + df.format(s.area()));
       // Displaying the perimeter of the square
       System.out.println("The Perimeter of Square is :" + df.format(s.perimeter()));

       /*
       * Creating the Hexagon class object by passing the length of the side
       * as argument
       */
       Hexagon h = new Hexagon(7);

       // Displaying the area of the Hexagon
       System.out.println("The Area of Hexagon is :" + df.format(h.area()));

       // Displaying the perimeter of the hexagon
       System.out.println("The Perimeter of Hexagon is :" + df.format(h.perimeter()));

   }

}

_____________________

output:

The Area of Equilateral Traingle is :10.83
The Perimeter of Equilateral Traingle is :15
The Area of Square is :36
The Perimeter of Square is :24
The Area of Hexagon is :127.31
The Perimeter of Hexagon is :42

__________Thank YOu

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