import javax.swing.*;
import java.awt.*;
/*
* Point2D.java
*
* Created on October 26, 2004, 2:31 AM
*/
/**
*
* @author DVS
*/
public class Point2D {
public int x, y;
/** Creates a new instance of Point2D */
public Point2D() {
x = 0;
//y=0;
}
public Point2D(int tx, int ty){
x = tx;
this.y = ty;
}
private double distOrig(){
double d;
d = Math.sqrt(x*this.x + y*y);
return d;
}
private double distFrom(Point2D t){
double d;
d = (x - t.x)*(x - t.x) + (this.y - t.y)*(y - t.y);
d = Math.sqrt(d);
return d;
}
public static void main(String argv[]){
Point2D p1, p2, p3;
Circle c1, c2;
p1 = new Point2D();
System.out.println("Hello World");
System.out.println("x = "+p1.x+" y = "+p1.y);
p2 = new Point2D(10, 20);
System.out.println("Hello World");
System.out.println("x = "+p2.x+" y = "+p2.y);
System.out.println("The distance from the origen is: "+p2.distOrig());
p3 = new Point2D(10,50);
System.out.println("The distance between points is: "+p2.distFrom(p1));
c1 = new Circle(10);
c2 = new Circle(10, 10, 5);
System.out.println("Radius = "+c1.radius);
System.out.println("center at "+c1.x+" and "+c1.y);
System.out.println("area is "+c1.area());
System.out.println("-------------------------------------");
System.out.println("Radius = "+c2.radius);
System.out.println("center at "+c2.x+" and "+c2.y);
System.out.println("area is "+c2.area());
// GUI examples
JFrame f = new JFrame("My Test Frame");
f.getContentPane().setLayout(new FlowLayout());
JButton button1;
JTextField field = new JTextField("Some text", 10);
button1 = new JButton("My Button");
f.getContentPane().add(button1);
f.getContentPane().add(field);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(200, 300);
f.setVisible(true);
}
}
/*
Note that the instance variables are private/public. Both the methods are also
declared private, however they can be used within the class including the main method.
*/
class Circle extends Point2D{
int radius;
public Circle(int r){
super();
radius = r;
}
public Circle(int cx, int cy, int cr){
super(cx,cy);
radius = cr;
}
public double area(){
return Math.PI*radius*radius;
}
// circumference method here - returns a double value
}