area of circle in java

1import java.util.Scanner;
2public class CalculateAreaOfCircle
3{
4   public static void main(String[] args)
5   {
6      double radius;
7      double pi = 3.1415, area;
8      Scanner sc = new Scanner(System.in);
9      System.out.println("Please enter radius of circle: ");
10      radius = sc.nextDouble();
11      area = pi * radius * radius;
12      System.out.println("Area of circle: " + area);
13      sc.close();
14   }
15}

1import java.util.Scanner;
2public class AreaOfCircle {
3   public static void main(String args[]){
4      int radius;
5      double area;
6      Scanner sc = new Scanner(System.in);
7      System.out.println("Enter the radius of the circle ::");
8      radius = sc.nextInt();
9      area = (radius*radius)*Math.PI;
10      System.out.println("Area of the circle is ::"+area);
11   }
12}

1public class scratch {
2    public static void main(String[] args) {
3        JFrame window = new JFrame();
4        window.setTitle("Christmas Tree");
5        window.setSize(700, 600);
6        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
7        window.setVisible(true);
8        DrawingComponent DC = new DrawingComponent();
9        window.add(DC);
10    }
11}
12class DrawingComponent extends JComponent{
13      public void paint(Graphics graph0){
14        Graphics2D graph = (Graphics2D) graph0;
15        Ellipse2D.Double circle = new Ellipse.Double(5, 5, 25, 25);
16        graph.fill(circle);
17      }
18}

1import java.util.Scanner;
2
3public class Main {
4
5    public static void main(String[] args) {
6
7        final  float PI = 3.14f;
8        Scanner scanner = new Scanner(System.in);
9
10        System.out.print("Enter radius of circle: ");
11        int radius = scanner.nextInt();
12
13        double areaOfCircle = PI * Math.pow(radius,2);
14
15        System.out.printf(" Area of circle of circle is %.2f ",areaOfCircle);
16    }
17}
18

1import java.util.Scanner;
2
3public class Main {
4    public static void main(String[] args){
5        double R,A;
6        Scanner sc = new Scanner(System.in);
7        R = sc.nextDouble();
8        A = 3.14159 * R * R;
9        System.out.printf("A=%.4f\n",  A);
10   }
11}