具有用户输入的二次方程求解器

/**
n o w  j a v a  . c o m 提供 
**/

import java.util.Scanner;


public class Main {

    public static void main(String[] arg) {

        Scanner keyboard = new Scanner(System.in);


        System.out.print("Enter a,b,c of equation ax^2+bx+c=0:");

        double a = keyboard.nextDouble();

        double b = keyboard.nextDouble();

        double c = keyboard.nextDouble();


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

        double root1, root2;
/** 时代Java - nowjava.com 提 供 **/

        if (delta >= 0) {

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

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

            System.out.println(