private TextField lvl, len;

vonKoch() {

super("von Koch snowflake");

Label lvlLbl = new Label("level");

lvl = new TextField("4",3);

Label lenLbl = new Label("side");

len = new TextField("200",3);

Button draw = new Button("draw");

lvl.addActionListener(this);

len.addActionListener(this);

draw.addActionListener(this);

setLayout(new FlowLayout());

add(lvlLbl);

add(lvl);

add(lenLbl);

add(len);

add(draw);

setSize(600,400);

setForeground(Color.white);

setBackground(Color.red);

show();

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0);

}

});

}

private double angle;

private Point currPt, pt = new Point();

private void right(double x) {

angle += x;

}

private void left (double x) {

angle -= x;

}

private void drawFourLines(double side, int level, Graphics g) {

if (level == 0) {

// arguments to sin() and cos() must be angles given in radians,

// thus, the angles given in degrees must be multiplied by PI/180;

pt.x = ((int)(Math.cos(angle*Math.PI/180)*side)) + currPt.x;

pt.y = ((int)(Math.sin(angle*Math.PI/180)*side)) + currPt.y;

g.drawLine(currPt.x, currPt.y, pt.x, pt.y);

currPt.x = pt.x;

currPt.y = pt.y;

}

else {

drawFourLines(side/3.0,level-1,g);

left (60);

drawFourLines(side/3.0,level-1,g);

right(120);

drawFourLines(side/3.0,level-1,g);

left (60);

drawFourLines(side/3.0,level-1,g);

}

}

public void actionPerformed(ActionEvent e) { // ActionListener

repaint();

}

public void paint(Graphics g) {

int level = Integer.parseInt(lvl.getText().trim());

double side = Double.parseDouble(len.getText().trim());

currPt = new Point(200,150);

angle = 0;

for (int i = 1; i <= 3; i++) {

drawFourLines(side,level,g);

right(120);

}

}

static public void main(String[] a) {

new vonKoch();

}