Q.  Create an abstract class Shape with methods calc_area and calc_volume. Derive three classes Sphere(radius) , Cone(radius, height) and Cylinder(radius, height), Box(length, breadth, height) from it. Calculate area and volume of all. (Use Method overriding).


Program:

import java.io.*;

abstract class Shape{
abstract public void calc_area();
abstract public void calc_volume();
final float pi=3.14f;
}

class Sphere extends Shape{
double r;
private double area;
private double volume;
public void accept() throws IOException{
System.out.println("Enter the radius of the Sphere: ");
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
r=Double.parseDouble(br.readLine());
}
public void calc_area(){
area=pi*r*r;
}
public void calc_volume(){
volume=1.33333333334*pi*r*r*r;
}
public void display(){
calc_area();
calc_volume();
System.out.println("The area of sphere is: "+area);
System.out.println("The volume of sphere is: "+volume);
}
}

class Cone extends Shape{
double h,r,area,volume;

public void accept() throws IOException{
System.out.println("Enter radius and height of the Cone: ");
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
r=Double.parseDouble(br.readLine());
h=Double.parseDouble(br.readLine());
}
public void calc_area(){
double sq=h*h+r*r;
area=pi*r*(r+java.lang.Math.sqrt(sq));
}
public void calc_volume(){
double d=h/3;
volume=pi*r*r*d;
}
public void display(){
calc_area();
calc_volume();
System.out.println("The area of Cone is: "+area);
System.out.println("The volume of Cone is: "+volume);
}
}

class Cylinder extends Shape{
double r,h,area,volume;
public void accept() throws IOException{
System.out.println("Enter radius and height of the Cylinder: ");
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
r=Double.parseDouble(br.readLine());
h=Double.parseDouble(br.readLine());
}
public void calc_area(){
area=(2*pi*r*h)+(2*pi*r*r);
}
public void calc_volume(){
volume=pi*r*r*h;
}
public void display(){
calc_area();
calc_volume();
System.out.println("The area of Cylinder is: "+area);
System.out.println("The volume of Cylinder is: "+volume);
}
}

class Box extends Shape{
double l,b,h,area,volume;
public void accept() throws IOException{
System.out.println("Enter length, breadth and height of the Box: ");
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
l=Double.parseDouble(br.readLine());
b=Double.parseDouble(br.readLine());
h=Double.parseDouble(br.readLine());
}
public void calc_area(){
area=(2*l*b)+(2*b*h)+(2*l*h);
}
public void calc_volume(){
volume=l*b*h;
}
public void display(){
calc_area();
calc_volume();
System.out.println("The area of Box is: "+area);
System.out.println("The volume of Box is: "+volume);
}
}

public class sa2 {
public static void main(String [] args)throws IOException{
Sphere s=new Sphere();
s.accept();
s.display();
Cone co=new Cone();
co.accept();
co.display();
Cylinder cy=new Cylinder();
cy.accept();
cy.display();
Box b=new Box();
b.accept();
b.display();
}
}

Output:

Enter the radius of the Sphere: 
2
The area of sphere is: 12.5600004196167
The volume of sphere is: 33.49333445247866

Enter radius and height of the Cone: 
2
12
The area of Cone is: 88.95950035259106
The volume of Cone is: 50.2400016784668

Enter radius and height of the Cylinder: 
2
12
The area of Cylinder is: 175.8400058746338
The volume of Cylinder is: 150.7200050354004

Enter length, breadth and height of the Box: 
12
14
15
The area of Box is: 1116.0
The volume of Box is: 2520.0