// daypr.java
// daily production and consumption
// adapted from a program in basic by H.T. Odum & E. Odum, 1994

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

public class daypr extends Applet
{

 Label prompt1, prompt2;
 TextField input1, input2;
 Button drawbutton;
 double TN, K, K1, K2, K3, t, ti, Q, Qi, J, Ji, N, Ni, DQ, JR;

 public void init()
 {
 	prompt1 = new Label("TN Total available nutrients: ");
	input1 = new TextField("10", 5);
	add(prompt1); add(input1);

	prompt2 = new Label("K2 Decreasing coefficient: ");
	input2 = new TextField("4", 3);
	add(prompt2); add(input2);

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

 public boolean action(Event e, Object o)
 {
 	TN = (float)Integer.parseInt(input1.getText());
 	K2 = (float)Integer.parseInt(input2.getText());
 	repaint();
 	return true;
 }

 public void paint(Graphics g)
 {
 	g.drawRect(0,60,320,250);
 	t=0; Q=5; J=0; TN=TN/10;
	K=0.9; K1=0.2; K2=K2/100; K3=0.01f;
	N=TN-K3*Q;

	g.drawLine(0,200,320,200);

 	while (t<320)
 	{
		ti=t+1;
		Ji=40*Math.sin(ti/15.9);
		if(Ji<0)Ji=0;
		JR=J/(1+K*N);
		DQ=K1*JR*N-K2*Q;
		Qi=Q+DQ;
		Ni=TN-K3*Qi;
		g.setColor(Color.blue);
		g.drawLine((int)t, (int)(200-0.5*Q), (int)ti, (int)(200-0.5*Qi));
		g.setColor(Color.green);
		g.drawLine((int)t, (int)(310-50*N), (int)ti, (int)(310-50*Ni));
		g.setColor(Color.red);
		g.drawLine((int)t, (int)(120-J), (int)ti, (int)(120-Ji));
		N=Ni; Q=Qi; J=Ji; t=ti;
	}
  }
}
// Manuel Basler & E. Ortega, October 6th 2000*/