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

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

public class macroec extends Applet
{

  Label prompt1,prompt2,prompt3;
  TextField input1,input2,input3;
  double E,k2,k5;
  Button drawbutton;

  public void init()
  {
	    prompt1 = new Label("E Energy source: ");
		input1 = new TextField("2",4);
		add(prompt1);add(input1);

		prompt2 = new Label("K2 Depreciation rate of the growing assets: ");
		input2 = new TextField("45",4);
		add(prompt2);add(input2);

		prompt3 = new Label("K5 percent of income saved and reinvested: ");
		input3 = new TextField("10",4);
		add(prompt3);add(input3);

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

  public boolean action(Event e, Object o)
  {
	  E=(float)Integer.parseInt(input1.getText());
	  k2=0.01*(float)Integer.parseInt(input2.getText());
	  k5=0.1*(float)Integer.parseInt(input3.getText());
	  repaint();
	  return true;
  }

  public void paint(Graphics g)
  {
    g.drawRect(0,90,320,210);
    int t;
	double x,kz,j,y,s,i,c,k,pr,r;
	double dt,dk,t0,y0;
	double k0,k1,k3,k4,k6;

	x=0; t=0; dk=0; kz=3; j=100; y=10; s=kz*y; i=s; c=y-s;k=10;
	dt=0.1; t0=10; y0=3;
	k0=0.1; k1=1; k3=1; k4=0.011; k6=0.00011;

	do
	{
		if (y*y0>180) g.setColor(Color.blue);
		g.drawOval(t,(int)(300-y*y0),1,1);

		if (k*kz>180) g.setColor(Color.red);
		g.drawOval(t,(int)(300-k*kz),1,1);

		if (x==0)
		{
			dk=k3*i-k6*E*c*k-k2*k;
			pr=k4*c*k*E;// duvida
	    }
		else
		{
			r=j/(1+k0*k*c);//duvida
	        pr=k4*c*k*r;
		    y=k1*pr;
		    s=k5*y;
		    i=s;
		    c=y-s;
	    }

	    k=k+dk*dt; // duvida
	    if (k<0.00001) k=0.00001;
	    t=t+1;
	}
	while(t<=320);
 }
}
// Camila Duarte & E. Ortega, January 30th, 2001