//QuadraticFormula.java

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

public class QuadraticFormula extends JApplet {     

    public void init() {
	
	double a, b, c, 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);

	x1 = (-b + Math.sqrt(b*b - 4*a*c)) / (2 * a);
	x2 = (-b - Math.sqrt(b*b - 4*a*c)) / (2 * a);
	
	JOptionPane.showMessageDialog(null, "x1="+x1+"  x2="+x2);
    }
}
//we'll learn how to deal with a==0 and discriminant<0 later