具有双值的二次方程求解器

/*来自 
 NowJava.com - 时代Java*/

import java.util.Locale;

import java.util.Scanner;


public class Main {

    public static void main(String[] arg) {

        double a=1, b=1, c=1;

        double delta = b * b - 4.0 * a * c;

        double root1, root2;


        /*

        // BEWARE: potentially Not a Number (NaN) for neg. discriminant!

        root1= (-b-Math.sqrt(delta))/(2.0*a);

        root2= (-b+Math.sqrt(delta))/(2.0*a);

        */

        if (delta >= 0.0d) {

            root1 = (-b - Math.sqrt(delta)) / (2.0 * a);

            root2 = (-b + Math.sqrt(delta)) / (2.0 * a);

            System.out.println("root1=" + root1 + " root2=" + root2);

        }