// sales.java
// sale with price inverse to supply
// adapted from a program in basic by H.T. Odum & E. Odum, 1994

import java.applet.*;
import java.awt.*;

public class sales extends Applet
{
  Label prompt1, prompt2, prompt3, prompt4;
  TextField input1, input2, input3, input4;
  double j,m,q,p;
  Button drawbutton;

 public void init()
 {
   prompt1 = new Label("J Energy: ");   input1 = new TextField("1", 3);  add(prompt1); add(input1);
   prompt2 = new Label("M Money: ");    input2 = new TextField("5", 3);   add(prompt2); add(input2);
   prompt3 = new Label("Q Products: "); input3 = new TextField("10", 3);   add(prompt3); add(input3);
   prompt4 = new Label("P Price: ");    input4 = new TextField("1", 3);   add(prompt4); add(input4);
   drawbutton = new Button("Draw"); add(drawbutton);
 }

 public boolean action(Event e, Object o)
 {
  j = (float)Integer.parseInt(input1.getText());
  m = (float)Integer.parseInt(input2.getText());
  q = (float)Integer.parseInt(input3.getText());
  p = (float)Integer.parseInt(input4.getText());
  repaint();  return true;
 }

 public void paint(Graphics g)
 {
  int t, ti, t0, dt;
  double k1,k2,k3,k4,  q0,p0,m0,  dq,dm,  mi,qi,pi;

  g.drawRect(0,60,320,240);

  k1=0.005; k2=0.005; k3=0.05; k4=1500;
  q0=0.3;   p0=1;     m0=0.5;
  mi=0;     qi=0;     pi=0;
  t=0;      ti=0;     dt=1;     t0=1;

  do {
   p=k4/q;
   dq=j-k1*q-k2*q;
   dm=(k2*q)*p-k3*m;
   qi=q+(dq*dt);
   mi=m+(dm*dt);
   pi=k4/qi;
   ti=t+dt;

   g.setColor(Color.red);
   g.drawLine(t, (int)(300-(q*q0)), ti, (int)(300-(qi*q0)));
   g.setColor(Color.green);
   g.drawLine(t, (int)(300-(p*p0)), ti, (int)(300-(pi*p0)));
   g.setColor(Color.blue);
   g.drawLine(t, (int)(300-(m*m0)), ti, (int)(300-(mi*m0)));

   q=qi; m=mi;	t=ti; p=pi;
  } while (t<320);

 }

}
// Camila Duarte & e. Ortega, December 6th 2000*/