java NaN and -infinity

Question

如果结果等于nan或-infinity，我无法找出一种捕捉或给我程序的订单。每当我将0输入我的程序时，它都会给我NAN和-Infinity的结果。我面临的问题是X1和X2是双重类型，显然无法与字符串类型进行比较。任何帮助将不胜感激。

public class Exercise {
public static void main(String[] args){
    double x1 = 0;
    double x2 = 0;
    Scanner scanner = new Scanner(System.in);
    System.out.println("Feed me with a, b and c");
    try{
            double a = scanner.nextDouble();
            double b = scanner.nextDouble();
            double c = scanner.nextDouble();
            scanner.close();
            double discriminant = (b * b) - 4 * (a * c);
        if (discriminant > 0){
            x1 = (-b + Math.sqrt(discriminant)) / (2 * a);
            x2 = (-b - Math.sqrt(discriminant)) / (2 * a);
            System.out.println("The dish of yours has two components " + x1 
        + " and " + x2);
        }
        if (discriminant == 0){
            x1 = -b / (2 * a);
            System.out.println("The dish of yours has two identical 
        components " + x1 +" and " + x1);
        }
        if (discriminant < 0){
            System.out.println("The dish of yours doesn't have any 
         component");
        }
        }
        catch (InputMismatchException e) {
            System.out.println("I can't digest letters");
        }
        catch (Exception e) {
            System.out.println("This is inedible");
    }
    }
    }

Answer 1

您可以通过执行

检查NaN

if (Double.isNaN(yourResult)) { ... }

和无限制：

if (Double.isInfinite(yourResult)) { ... }

您绝不应该使用==检查NaN，因为NaN被认为不等于NaN！

或者，您可以检查a是否为0。因为这可能是Infinity和Nan出来的唯一情况。如果是，请说"我的菜在哪里？"：(

另外，我只是尝试给出Nan NaN NaN，但什么也没输出。考虑检查A，B和C是否也是NAN或无限态度。：(

Answer 2

简单地可以通过在使用之前验证输入A，B和C来避免您的错误。

。

ex：检查a！= 0。