第3章：代数方面：解一元二次方程

/** * 代数方面：解一元二次方程。 * 提示用户输入a、b和c的值: * 显示基于判别式的结果。 * 如果这个判别式为正，显示两个根。 * 如果判别式为0，显示一个根。 * 否则，显示“The equation has no real roots!”。 */package Test;import java.util.Scanner;public class T31Scanner {public static void main(String[] args) {Scanner input = new Scanner(System.in);System.out.print("Enter a, b, c: ");double a = input.nextDouble();double b = input.nextDouble();double c = input.nextDouble();double discriminant = Math.pow(b * b - 4 * a * c, 0.5);double r1 = (-b + discriminant) / (2 * a);double r2 = (-b - discriminant) / (2 * a);if (discriminant > 0)System.out.println("the roots are " + r1 + " and " + r2 + "!");elseSystem.out.println((discriminant == 0) ? "the roots is " + r1 : "The equation has no real roots!");}}