java - 输入验证 Java

Question

我对 Java 还很陌生。我正在编写一个程序，根据一个人的婚姻状况计算所得税摘要。我的程序可以正常工作，但有一个问题:我的婚姻状况输入验证部分无法正常工作。当我输入 s、S、m、M、c 和 C 以外的内容时，程序应该对此执行输入验证，但目前，当我输入 x 之类的内容时，它会跳过总收入和免税额，并吐出得出税率、应缴税款、应纳税所得额均为0。

编辑:抱歉，如果这令人困惑。基本上，如果用户使用无效输入，然后用户输入有效内容，我想知道如何使其返回到 switch 语句的开头来确定税率 任何帮助将不胜感激!

import java.util.Scanner;

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

        char maritalStatus;
        double grossIncome = 0;
        double numberOfExemptions = 0;
        double taxRate = 0;
        double taxableIncome = 0;
        double taxesOwed = 0;
        String anotherCustomer = "y";

        System.out.print("_ _ _ _ _ ' S  T A X  P R E P A R E R\n\n");

        do{
            System.out.print("Are you (s)ingle, (m)arried, or (c)ohabiting?\n");
            System.out.print("Enter s, m, or c ==> ");
            maritalStatus = sc.next().charAt(0);
            switch (maritalStatus)
            {
                case 's': case 'S':
                    System.out.print("Gross income ==> ");
                    grossIncome = sc.nextDouble();
                    System.out.print("Number of exemptions ==> ");
                    numberOfExemptions = sc.nextInt();
                    taxableIncome = grossIncome - (1000 * numberOfExemptions);
                    taxRate = 20;
                    break;
                case 'm': case 'M':
                    System.out.print("Gross income ==> ");
                    grossIncome = sc.nextDouble();
                    System.out.print("Number of exemptions ==> ");
                    numberOfExemptions = sc.nextInt();
                    taxableIncome = grossIncome - (1000 * numberOfExemptions);
                    taxRate = 25;
                    break;
                case 'c': case 'C': //tax rate for cohabiting depends on taxable income
                    System.out.print("Gross income ==> ");
                    grossIncome = sc.nextDouble();
                    System.out.print("Number of exemptions ==> ");
                    numberOfExemptions = sc.nextInt();
                    taxableIncome = grossIncome - (1000 * numberOfExemptions);
                    if (taxableIncome <= 20_000)
                    {
                        taxRate = 10;
                        break;
                    }
                    else if (taxableIncome <= 50_000)
                    {
                        taxRate = 15;
                        break;
                    }
                    else
                    {
                        taxRate = 30;
                        break;
                    }
                default: //if input for marital status is invalid
                    do{ //continues to ask for valid input until user inputs a valid marital status
                        System.out.print("\nInvalid entry.");
                        System.out.print("\nAre you (s)ingle, (m)arried, or (c)ohabiting?");
                        System.out.print("\nEnter s, m, or c ==> ");
                        maritalStatus = sc.next().charAt(0);
                    } while (maritalStatus != 's' && maritalStatus != 'S' && maritalStatus != 'm' && maritalStatus != 'M' && maritalStatus != 'c' && maritalStatus != 'C');
            } 

            taxesOwed = taxableIncome * (taxRate / 100);

            //taxable income and taxes owed cannot be negative
            if (taxableIncome < 0)
            {
                taxableIncome = 0;
            }
            if (taxesOwed < 0)
            {
                taxesOwed = 0;
            }

            //tax summary
            System.out.print("\nINCOME TAX SUMMARY");
            System.out.print("\ntax rate: " + taxRate + "%");
            System.out.print("\ntaxable income: $" + taxableIncome);
            System.out.print("\ntaxes owed: $" + taxesOwed);

            //would you like to process another customer?
            System.out.print("\n\nProcess another customer? (y/n): ");
            anotherCustomer = sc.next();
            System.out.print("\n");
        } while (anotherCustomer.equalsIgnoreCase("y")); //as long as user enters 'y' or 'Y', the program will continue to calculate the income tax summary
    }
}

Answer 1

而不是稍后重试

default: //if input for marital status is invalid
   do{ //continues to ask for valid input until user inputs a valid marital status
   } while(...);

简单地跳到外循环的末尾:

default:
    System.out.print("\nInvalid entry.");
    continue;