import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class Teljed2 extends Applet implements ActionListener{
  double a=3;
  TextField tf1=new TextField(String.valueOf(a));
  double b=5;
  TextField tf2=new TextField(String.valueOf(b));
  public Teljed2(){
    add(tf1);
    add(tf2);
    tf1.addActionListener(this);
    tf2.addActionListener(this);
  }
  public void paint(Graphics g){
    g.drawLine(100, 0, 100, getHeight());
    g.drawLine(  0, 200, getWidth(), 200);
    for(int x=-100; x<100; x++){
      g.drawOval(x+100, 200-(int)(a*x+b), 1, 1);
    }
    double nullkoht=-b/a;
    g.drawOval((int)nullkoht+100-5, 200-5, 10, 10);
  }
  public void actionPerformed(ActionEvent e){
     a=Double.parseDouble(tf1.getText());
     b=Double.parseDouble(tf2.getText());
     repaint();
  }


  public static void main(String argumendid[]){
    Frame f=new Frame("Ruutfunktsiooni graafik");
    f.add(new Teljed2());
    f.setSize(250, 250);
    f.setVisible(true);
  }
}