// moneygro.java
// money driven growth
// adapted from a program in basic by H.T. Odum & E. Odum, 1994

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

public class moneygro extends Applet
{

 Label prompt1,prompt2,prompt3;
 TextField input1,input2,input3;
 double a,k2,E;
 Button drawbutton;

 public void init()
 {
	prompt1 = new Label("A Economic assets: ");
	input1 = new TextField("2",4);
	add(prompt1);add(input1);

	prompt2 = new Label("K2 Depreciation rate: ");
	input2 = new TextField("20",4);
	add(prompt2);add(input2);

	prompt3 = new Label("E Availability of resources: ");
	input3 = new TextField("1",4);
	add(prompt3);add(input3);

	drawbutton = new Button("Draw"); add(drawbutton);
 }

 public boolean action(Event e, Object o)
 {
	a=0.1*(float)Integer.parseInt(input1.getText());
	k2=0.001*(float)Integer.parseInt(input2.getText());
	E=(float)Integer.parseInt(input3.getText());
	repaint();
	return true;
 }

 public void paint(Graphics g)
 {
	g.drawRect(0,90,320,210);
	int t;
	double k0,k1,m;
	double m0,a0,t0;
	double da,dt;
	t=0; k0=3.7; k1=0.0133; m=0;
	m0=100; a0=1; t0=0.5;
	da=0; dt=1;

	do
	{
	 g.setColor(Color.blue);
	 if (300-a*a0>90)
	 g.drawOval(t,(int)(300-a*a0),1,1);
	 else
	 g.drawOval(t,90,1,1);

	 g.setColor(Color.red);
	 if (300-m*m0>90)
	 g.drawOval(t,(int)(300-m*m0),1,1);
	 else
	 g.drawOval(t,90,1,1);

	 m=k1*a;
	 da=k0*E*m-k2*a;
	 a=a+da*dt;
	 t=t+1;
	}
	while (t<320);
 }
}
// Camila Duarte & E. Ortega, January 30th, 2001