Drawing the Quadratic formula with sliders on a JPanel

Question

So, I\'m trying to make a program where you can input the quadratic formula (ax^2+bx+c) via sliders. Then it draws a graph as you adjust for A, B, and C.

Issues:

<

Answer 1

I modified the code so that it solves for x given a b and c. Then plugs x back in and solves for y. I'm still not getting it to draw though. I also took out the loop since the sliders are setting the a b and c values which lead to x. Anyone know why it won't draw?

package quadraticslider;

import java.awt.*;
import javax.swing.*;

public class quadraticslider
{

     public static void main (String[] args)
   {
      JFrame frame = new JFrame ("Quadratic Slider");
      frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

      frame.getContentPane().add(new quadraticpanel());

      frame.pack();
      frame.setVisible(true);
   }
}

package quadraticslider;

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;

public class quadraticpanel extends JPanel
{
   private JPanel controls, graphPanel;
   private JSlider ASlider, BSlider, CSlider;
   private JLabel ALabel, BLabel, CLabel;
   double A, B, C, x,Y;


   public quadraticpanel()
   {
      ASlider = new JSlider (JSlider.HORIZONTAL, -25, 25, 0);
      ASlider.setMajorTickSpacing (50);
      ASlider.setMinorTickSpacing (10);
      ASlider.setPaintTicks (true);
      ASlider.setPaintLabels (true);
      ASlider.setAlignmentX (Component.LEFT_ALIGNMENT);

      BSlider = new JSlider (JSlider.HORIZONTAL, -25, 25, 0);
      BSlider.setMajorTickSpacing (50);
      BSlider.setMinorTickSpacing (10);
      BSlider.setPaintTicks (true);
      BSlider.setPaintLabels (true);
      BSlider.setAlignmentX (Component.LEFT_ALIGNMENT);

      CSlider = new JSlider (JSlider.HORIZONTAL, -25, 25, 0);
      CSlider.setMajorTickSpacing (50);
      CSlider.setMinorTickSpacing (10);
      CSlider.setPaintTicks (true);
      CSlider.setPaintLabels (true);
      CSlider.setAlignmentX (Component.LEFT_ALIGNMENT);

      SliderListener listener = new SliderListener();
      ASlider.addChangeListener (listener);
      BSlider.addChangeListener (listener);
      CSlider.addChangeListener (listener);


      ALabel = new JLabel ("a: 0");
      ALabel.setAlignmentX (Component.LEFT_ALIGNMENT);
      BLabel = new JLabel ("b: 0");
      BLabel.setAlignmentX (Component.LEFT_ALIGNMENT);
      CLabel = new JLabel ("c: 0");
      CLabel.setAlignmentX (Component.LEFT_ALIGNMENT);
      controls = new JPanel();
      BoxLayout layout = new BoxLayout (controls, BoxLayout.Y_AXIS);
      controls.setLayout (layout);
      controls.add (ALabel);
      controls.add (ASlider);
      controls.add (Box.createRigidArea (new Dimension (0, 20)));
      controls.add (BLabel);
      controls.add (BSlider);
      controls.add (Box.createRigidArea (new Dimension (0, 20)));
      controls.add (CLabel);
      controls.add (CSlider);



      graphPanel = new JPanel();
      graphPanel.setPreferredSize (new Dimension (500, 500));
      graphPanel.setBackground (Color.white);

      add (controls); 
      add (graphPanel);




   }   



     public void paintComponent(Graphics page)
   {  

     super.paintComponent (page);




         x = (-B + (Math.sqrt((B*B - ((4 * A * C))))))/ (2 * A);
         Y = (A*(Math.pow(x,2)))+(B*x)+(C);
         int g = (int)Math.round(x);
         int h = (int)Math.round(Y);
         page.setColor (Color.black);
         page.drawOval (g, h, 1, 1);



    }


   public class SliderListener implements ChangeListener
   {
///
///Reads the user input via slider.
///

      public void stateChanged (ChangeEvent event)
      {
         A = ASlider.getValue();
         B = BSlider.getValue();
         C = CSlider.getValue();

         ALabel.setText ("a: " + A);
         BLabel.setText ("b: " + B);
         CLabel.setText ("c: " + C);

      }

} }