/*
 * ftab.java - revised 20 Jan 08 - width 363, height 405
 * @author jackord@kw.igs.net
 * Euler/Feynman table
 *   
 */

import java.applet.Applet;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class ftab extends Applet 
                   implements ActionListener {
  int kk=0;
  String b1s="Print Table"; Button b1=new Button(b1s);

  public void init() {
    setBackground(new Color(211, 211, 211));           // Light Gray Background
    add(b1); b1.addActionListener(this);
  }

  public void paint(Graphics g) {
    float k, m, dt, t, y, v, a;
    int n, d, c1, c2, c3, c4, r;
    k=8; m=2; dt=(float).2;
    n=5; d=16; c1=11; c2=101; c3=191; c4=281; r=3*d;
    g.setColor(Color.black); g.drawRect(0, 32, 362, 372);
    if (kk>0) {
      g.setFont(new Font("TimesRoman", Font.PLAIN, 14));
// Euler Algorithm
      g.drawString("Euler Algorithm", c1, r); r=r+d;
      g.drawString("Time", c1, r); g.drawString("Position", c2, r);
      g.drawString("Velocity", c3, r); g.drawString("Acceleration", c4, r); r=r+d;
      t=0; y=0; v=(float)2.8; a=-k*y/m;
      g.drawString(""+t, c1, r); g.drawString(""+y, c2, r);
      g.drawString(""+v, c3, r); g.drawString(""+a, c4, r); r=r+d;
      for (int i=1; i<=n; i=i+1) {
        t=t+dt; y=y+v*dt; v=v+a*dt; a=-k*y/m;
        g.drawString(""+t, c1, r); g.drawString(""+y, c2, r);
        g.drawString(""+v, c3, r); g.drawString(""+a, c4, r); r=r+d;
      }
      r=r+d;
// Feynman Algorithm
      g.drawString("Feynman Algorithm", c1, r); r=r+d;
      g.drawString("Time", c1, r); g.drawString("Position", c2, r);
      g.drawString("Velocity", c3, r); g.drawString("Acceleration", c4, r); r=r+d;
      t=0; y=0; v=(float)2.8; a=-k*y/m;
      g.drawString(""+t, c1, r); g.drawString(""+y, c2, r);
      g.drawString(""+v, c3, r); g.drawString(""+a, c4, r); r=r+d;
      v=v+a*dt/2;
      g.drawString(""+(t+dt/2), c1, r); g.drawString(""+v, c3, r); r=r+d;
      for (int i=1; i<=n; i=i+1) {
        t=t+dt; y=y+v*dt; a=-k*y/m; v=v+a*dt;
        g.drawString(""+t, c1, r); g.drawString(""+y, c2, r);
        g.drawString(""+a, c4, r); r=r+d;
        g.drawString(""+(t+dt/2), c1,r); g.drawString(""+v, c3, r); r=r+d;
      }
      kk=0;
    }
  }

  public void actionPerformed(ActionEvent e) {         // Button
    String tst;
    tst=e.getActionCommand();
    if (b1s.equals(tst)) { kk=1; }
    repaint();
  }
     
}