用java画一个圆

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
class MyCanvas extends Canvas
{
int x,y,r,n;
int x0,y0;
MyCanvas()
{
setSize(100,100);
setBackground(Color.red);
}
public void setX(int x)
{
this.x=x;
}
public void setY(int y)
{
this.y=y;
}
public void setR(int r)
{
this.r=r;
}
public void setN(int n)
{
this.n=n;
}
public void paint(Graphics g1)
{
for(int i=0;i<=360;i=i+360/n)
{
x0 = (int)(x+r*Math.cos(i));
y0 = (int)(y+r*Math.sin(i));
g1.drawString("*",x0,y0);}
}
}
public class e1 extends Applet implements ActionListener
{
MyCanvas canvas;
TextField inputR,inputX,inputY,inputN;
Label label1,label2,label3;
Button b1,b2;
public void init()
{
canvas = new MyCanvas();
inputR = new TextF