public class PlayCircle2
1:
2: import java.util.*;
3:
4: public class PlayCircle2
5: {
6: public static final double PI = 3.14159;
7:
8: private double diameter;
9:
10: public static void main(String[] args)
11: {
12: PlayCircle circle = new PlayCircle( );
13: circle.setDiameter(2);
14: System.out.println("If circle has diameter 2,");
15: circle.showArea( );
16: System.out.println("Now you choose the diameter:");
17: PlayCircle.areaDialog( );
18: }
19:
20: public void setDiameter(double newDiameter)
21: {
22: diameter = newDiameter;
23: }
24:
25: public static double area(double radius)
26: {
27: return (PI*radius*radius);
28: }
29:
30: public void showArea( )
31: {
32: System.out.println("Area is " + area(diameter/2));
33: }
34:
35: public static void areaDialog( )
36: {
37: Scanner keyboard = new Scanner(System.in);
38: System.out.println("Enter the diameter of a circle:");
39: double newDiameter = keyboard.nextDouble( );
40: PlayCircle c = new PlayCircle( );
41: c.setDiameter(newDiameter);
42: c.showArea( );
43: }
44: }
45: