一个简单的画圆程序,怎么执行:public class Circle{
private int x;
private int y;
private float radius;
public Circle(){
x=0;
y=0;
radius=0;
}
public Circle(int x,int y,int radius){
this.x=x;
this.y=y;
this.radius=radius;
}
public void draw(){
System.out.println("draw a circle at a point:"+x+","+y);
}
public void erase(){
System.out.println("delete a circle");
x=0;
y=0;
}
}
private int x;
private int y;
private float radius;
public Circle(){
x=0;
y=0;
radius=0;
}
public Circle(int x,int y,int radius){
this.x=x;
this.y=y;
this.radius=radius;
}
public void draw(){
System.out.println("draw a circle at a point:"+x+","+y);
}
public void erase(){
System.out.println("delete a circle");
x=0;
y=0;
}
}
import javax.swing.*;
import java.awt.*;public class CircleFrame extends JFrame{ public static void main(String args[]) {
Circle myCircle = new Circle(0,0,100);
CircleFrame mainFrame = new CircleFrame();
mainFrame.getContentPane().add(myCircle);
mainFrame.setBounds(0,0,300,300);
mainFrame.show(); }
}
class Circle extends JPanel
{
private int x;
private int y;
private int radius; public Circle() {
x = 0;
y = 0;
radius = 0;
} public Circle(int x, int y, int radius) {
this.x = x;
this.y = y;
this.radius = radius;
} public void paint(Graphics g) {
//System.out.println("draw a circle at a point:" + x + "," + y);
g.drawOval(x,y,2*radius,2*radius);
} public void erase() {
System.out.println("delete a circle");
x = 0;
y = 0;
this.repaint();
}}
public static void main(String args[])
{
Circle myCircle = new Circle(0,0,100); }
public static void main(String args[])
{
Circle myCircle = new Circle(0,0,100);
myCircle.draw(); }