//Quadratic.java

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

public class Quadratic extends JApplet {     

    public void init() {
	
	double a, b, c, discriminant, x1, x2;
	String input;
	
	input = JOptionPane.showInputDialog("Enter a");
	a = Double.parseDouble(input);
	input = JOptionPane.showInputDialog("Enter b");
	b = Double.parseDouble(input);
	input = JOptionPane.showInputDialog("Enter c");
	c = Double.parseDouble(input);

	discriminant = b*b - 4*a*c;
	
	if (a == 0)
	    JOptionPane.showMessageDialog(null, "a can not be 0");

	else if (discriminant > 0) {
	    // calculate the two possible real values for x.
	    x1 = (-b + Math.sqrt(discriminant)) / (2 * a);
	    x2 = (-b - Math.sqrt(discriminant)) / (2 * a);
	    JOptionPane.showMessageDialog(null, "x1="+x1+"  x2="+x2);
	}
	else if (discriminant == 0) {
	    //one real root
	    x1 = -b / (2*a);
	    JOptionPane.showMessageDialog(null, "x="+x1);
	}
	else
	    //no real roots
	    JOptionPane.showMessageDialog(null, "Discriminant is negative");
	
    }
 }