// buypower.java  buying power with nonrenewable autocatalytic growth

// adapted from a program in basic by H.T. Odum & E. Odum, 1994.



import java.applet.Applet;

import java.awt.*;



/* <APPLET CODE="buypower.class" CODEBASE="." WIDTH=400 HEIGHT=400></APPLET> */



public class buypower extends Applet

{



 Label prompt1,prompt2,prompt3;

 TextField input1,input2,input3;

 double f,k3,k4;

 Button drawbutton;



 public void init()

 {

	prompt1 = new Label("F Fuel in the system: ");

	input1 = new TextField("100",4);

	add(prompt1);add(input1);



	prompt2 = new Label("K3 Conversion of fuels: ");

	input2 = new TextField("5",4);

	add(prompt2);add(input2);



	prompt3 = new Label("K4 Use of renewable energy");

	input3 = new TextField("7",4);

	add(prompt3);add(input3);



	drawbutton = new Button("Draw");

	add(drawbutton);

 }



 public boolean action(Event e, Object o)

 {

	f=1.0*(float)Integer.parseInt(input1.getText());

	k3=0.001*(float)Integer.parseInt(input2.getText());

	k4=0.01*(float)Integer.parseInt(input3.getText());

	repaint();

	return true;

 }



 public void paint(Graphics g)

 {



    double t, j,pw,q,m,r,p,pr;

    double k0,k1,k2,k5;

    double t0,q0,f0,p0,dt,df,dq;



    j=1; pw=0.01; q=0.01; m=2;

	k0=0.02; k1=0.00041; k2=0.00066; k5=0.05;

	t0=0.5; q0=1; f0=1.6; p0=3;

	dt=0.1;

	t=0; p=0; pr=0;



    g.drawRect(0,90,320,210);



	do

	{

	 g.setColor(Color.blue);

	 //if (300-p*p0>90)

	 g.drawOval((int)t,(int)(300-p*p0),1,1);

	 //else g.drawOval(t,90,1,1);



	 g.setColor(Color.green);

	 //if (300-q*q0>90)

	 g.drawOval((int)t,(int)(300-q*q0),1,1);

	 //else g.drawOval(t,90,1,1);



	 g.setColor(Color.red);

	 //if (300-pr>90)

	 g.drawOval((int)t,(int)(300-pr),1,1);

	 // else g.drawOval(t,90,1,1);



	 g.setColor(Color.magenta);

	 //if (300-f*f0>90)

	 g.drawOval((int)t,(int)(300-f*f0),1,1);

	 // else g.drawOval(t,90,1,1);



	 r=j/(1+k1*f*q+k0*q);

	 p=k3*r*f*q+k4*r*q+pw;

	 pr=100/p;

	 df=-k2*f*r*q;

	 dq=p-k5*q;

	 q=q+dq*dt;

	 f=f+df*dt;

	 t=t+dt;

	}

	while ((int)t<320);

 }

}

// Camila Duarte & E. Ortega, January 30th, 2001