9. Create class calculation with an abstract method area( ). Create Rectangle and Triangle subclasses of calculation and find area of rectangle and triangle.

 

import java.util.*;

abstract class Calculation

{

    abstract void area();

    double area;

}

class Rectangle extends Calculation

{

    double l;

    void area()

    {

        System.out.print("\nenter l for Rectangle: ");

        Scanner sc = new Scanner(System.in);

        l = sc.nextDouble();

       

        area = l * l;

        System.out.println("\narea of rectangle: " + area);

    }

}

class Triangle extends Calculation

{

    double l,b;

    void area()

    {

        System.out.print("\nenter l  for Triangle: ");

        Scanner sc = new Scanner(System.in);

        l = sc.nextDouble();

        System.out.print("\nenter b  for Triangle: ");

        b = sc.nextDouble();

       

        area = (l*b)/2;

        System.out.println("\narea of triangle: " + area);

    }

}

class Program9

{

    public static void main(String args[])

    {

        Triangle t1 = new Triangle();

        t1.area();

       

        Rectangle r1 = new Rectangle();

        r1.area();

    }

}