import javax.swing.*;
import java.awt.*;
import static java.lang.Math.*;

/*
<applet code="N_gon.class" width="220" height="220"> 
</applet>
*/

public class N_gon extends JApplet {
  @Override  
  public void paint(Graphics g) {
    super.paint(g);

    int np = 7;
    int sc = 100;

    int i;
    double theta1, theta2;
    for(i = 0; i < np; i++) {
      // 単位 ラジアン
      theta1 = PI * 2 * i / np;       // 360 * i / n度
      theta2 = PI * 2 * (i + 1) / np; // 360 * (i + 1) / n度
      g.drawLine((int)(sc * (1.1 + cos(theta1))), 
   		 (int)(sc * (1.1 + sin(theta1))),
                 (int)(sc * (1.1 + cos(theta2))),
   		 (int)(sc * (1.1 + sin(theta2))));
    }
  }

  public static void main(String[] args) {
    JFrame frame = new JFrame("");
    JApplet applet = new N_gon();
    applet.setPreferredSize(new Dimension(220, 220));
    frame.add(applet);
    frame.pack();
    frame.setVisible(true);
    applet.init();
    applet.start();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}