Hot，可防止在输入String(而不是int)后停止程序崩溃 [英] Hot to stop the program from crashing after a String is entered instead of an int

问题描述

当输入String而不是int时，如何防止崩溃? 这就是我所拥有的.我尝试查找一些教程，但仍然无法弄清楚. 感谢您的帮助.输入字符串时，我需要它告诉用户输入一个整数

How do I stop this from crashing when a String is entered instead of an int? Here is what i have. I've tried looking up some tutorials but I still couldn't figure it out. Thanks for the help guys. When a String is entered i need it to tell the user to enter an int

import java.util.Scanner;

    public class TaxCalc
    {
        public static void main(String [] args)
        {
          Scanner keyboard = new Scanner(System.in);

          int dependents = inputInt("Enter number of dependents: ", keyboard);

          int pigs = inputInt("Enter number of pigs: ", keyboard);

          double oinks= inputInt("Enter number of oinks: ", keyboard) -(pigs*500)+(200*dependents);

          System.out.println("Oinks after rewards: " + oinks);

          if(oinks<10000) oinks -= oinks*0.02; //2% tax
          else if(oinks<5000) oinks -= oinks*0.1; //10% tax
          else oinks -= oinks*0.2; //20% tax
          System.out.println("Oinks after penalties: " + oinks);
        }

    public static int inputInt(String prompt, Scanner keyboard){
        System.out.println(prompt);
        return keyboard.nextInt();
    }

    public double inputDouble(String prompt, Scanner keyboard){
        System.out.println(prompt);
        return keyboard.nextDouble();
    }
}

推荐答案

通过检查InputMismatchException，您可以通知用户他们输入了无效的输入，并且可以要求他们仅重新输入数字.

By checking the InputMismatchException you can inform the users that they have entered an invalid input, and you can ask them to re-enter only Numbers.

public static int inputInt(String prompt, Scanner keyboard) {
        System.out.print(prompt);
        try{
            return keyboard.nextInt();
        } catch (InputMismatchException e){
            System.out.println("Input Mismatch! Please enter Numbers");
            keyboard.next();
            return inputInt(prompt, keyboard);
        }
}

也等于两倍

希望您期待这一件事.如果没有，请评论您的requiremet.

hope you expected this one. if not please kindly comment your requiremet.

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