4

4).Shapeclass.java

import java.util.*;

abstract class shape

{

int a,b;

abstract public void printarea();

}

class rectangle extends shape

{

public int area_rect;

public void printarea()

{

Scanner s=new Scanner(System.in);

System.out.println("Enter the length and breadth of rectangle");

a=s.nextInt();

b=s.nextInt();

area_rect=a*b;

System.out.println("Length of rectangle: "+a +"breadth of rectangle: "+b);

System.out.println("The area of rectangle is:"+area_rect);

}

}

class triangle extends shape

{

double area_tri;

public void printarea()

{

Scanner s=new Scanner(System.in);

System.out.println("Enter the base and height of triangle:");

a=s.nextInt();

b=s.nextInt();

System.out.println("Base of triangle: "+a +"height of triangle: "+b);

area_tri=(0.5*a*b);

System.out.println("The area of triangle is:"+area_tri);

}

}

 class circle extends shape

{

double area_circle;

public void printarea()

{

Scanner s=new Scanner(System.in);

System.out.println("Enter the radius of circle:");

a=s.nextInt();

area_circle=(3.14*a*a);

System.out.println("Radius of circle:"+a);

System.out.println("The area of circle is:"+area_circle);

}

}

public class Shapeclass

{

public static void main(String[] args)

{

rectangle r=new rectangle();

r.printarea();

triangle t=new triangle();

t.printarea();

circle r1=new circle();

r1.printarea();

}

}