当分母为0时，如何更改消息“无穷大”？

Question

我是一个高中学生，我们有一个项目，创建一个计算器，其中一个任务是改变消息“无限”为“未定义”，有什么建议吗？

import java.util.Objects;
import java.util.Scanner;

public class Calculator {    

    public static void plus(int a, int b) {
        System.out.println(a + b);
    }

    public static void minus(int a, int b) {
        System.out.println(a - b);
    }

    public static void multiply(int a, int b) {
        System.out.println(a * b);
    }

    public static double divide(double a, double b) {
        double c = (a / b);
        return c;    
    }

    public static void main(String[] args) {

        System.out.println("Menu");
        System.out.println("type [+] = Addition");
        System.out.println("type [-] = Subtraction");
        System.out.println("type [*] = Multiplication");
        System.out.println("type [/] = Division");

        Scanner input = new Scanner(System.in);

        System.out.println("Enter the first operand: ");
        int number_a = input.nextInt();
        System.out.println("Enter the operator: ");
        String operator = input.next();
        System.out.println("Enter the second operand: ");
        int number_b = input.nextInt();
        System.out.println("Mathematical expression = " + number_a + operator + number_b);

        if (operator.equals("+")) {    
            plus(number_a, number_b);    
        } else if (operator.equals("-")) {    
            Calculator.minus(number_a, number_b);    
        } else if (operator.equals("*")) {    
            Calculator.multiply(number_a, number_b);    
        } else if (operator.equals("/")) {    
            System.out.println(Calculator.divide(number_a, number_b));    
        } else System.out.println("Please enter a valid mathematical operator");
    }
} 

Answer 1

试试这个。

static void divide(double a, double b) {
    double c = a / b;
    String s;
    if (c == Double.POSITIVE_INFINITY || c == Double.NEGATIVE_INFINITY || c == Double.NaN)
        s = "Undefined";
    else
        s = Double.toString(c);
    System.out.println(s);
}