Question

所以我开始研究用Java创建GUI的基础知识。我首先创建了一个基本的数学程序，它将解决Quadratic，其中输入通过Option Pane进行定向。但是，我注意到，只要没有想象的解决方案，程序就会给我解决方案。这是代码：

package window.math;
import javax.swing.JOptionPane;

public class WindowMath {

public static void Solve(double a, double b, double c){ //Gives the input of A, B, C to the formula
    double x;
    x = Math.pow(b,2) - 4 * a * c; //Determines whether solution will have imaginary numbers or not
    if (x >= 0){ //Real Solution output
        double y;
        double z;
        double j;
        double k;
        double l;
        y = -b + Math.sqrt(x);
        z = -b - Math.sqrt(x);
        j= 2 * a;
        k = y / j;
        l = z / j;
        JOptionPane.showMessageDialog(null, "The solutions are x = " + k + " and x = " + l + ".", "Quadratic Solver", JOptionPane.PLAIN_MESSAGE);
    } else { //Imaginary Solution Output
        double j;
        double v;
        double w;
        double y;
        double z;
        y = Math.abs(x);
        w = Math.sqrt(y);
        j = 2 * a;
        v = w / j;
        z = -b / j;
        JOptionPane.showMessageDialog(null, "The solutions are x = " + z + " + " + v + "i and x = " + z + " - " + v + "i.", "Quadratic Solver", JOptionPane.PLAIN_MESSAGE);
    }
}
public static void main(String[] args) {
    String a = JOptionPane.showInputDialog("Enter a:");
    String b = JOptionPane.showInputDialog("Enter b:");
    String c = JOptionPane.showInputDialog("Enter c:");
    double num1 = Double.parseDouble(a);
    double num2 = Double.parseDouble(b);
    double num3 = Double.parseDouble(b);
    Solve(num1,num2,num3);
}

}

当我运行三个数字给出解决方案的虚数时，程序运行正常。但是，对于类似a = 1，b = 2和c = 1的问题，解决方案应该是x = -1，x = -1。只有真正的解决方相反，输出给我“x = -1.0 + 1.0i，x = -1.0 - 1.0i。我目前正在NetBeans IDE 8.2（Build 201609300101）中编码，并使用Java更新1.8.0_144和JavaVM 25.144-b01。帮助将不胜感激。

Answer 1

代码中的问题位于以下行（来自main方法）：

double num3 = Double.parseDouble (b);

应该是：

double num3 = Double.parseDouble (c);

使用javax.swing.JOptionPane进行输入时的计算错误

1 个答案: