Program to demonstrate classes, objects and methods

import java.util.Scanner;

class Circle {

  double radius,area;

 

  void setData(double x) {

    radius=x;

  }

 

  void calculate() {

    area=3.14*radius*radius;

    System.out.println("Area is: "+area);

  }

}

class CircleEx {

  public static void main(String args[]) {

    double x;

    Scanner sc=new Scanner(System.in);

    Circle c=new Circle();

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

    x=sc.nextDouble();

    c.setData(x);

    c.calculaute();

  }

}

OUTPUT:

C:\jdk1.7.0\bin>java CircleEx

Enter radius of circle: 1

Area is: 3.14