java - 创建java代码提示用户输入密码并只允许尝试3次然后退出程序

Question

我一直在尝试让下面的代码在不使用break语句的情况下运行(但我无法弄清楚)

import java.io.*;
import java.util.*;

public class Password
{
    public static void main (String [] args)
    {
        final String PASSWORD = "Test";

        for (int passAttempts = 0; passAttempts < 3; passAttempts++) 
        {
            System.out.print("\nEnter Your Password: ");
            Scanner input = new Scanner(System.in);
            String inputPass = input.nextLine();

            if (!(inputPass.equals(PASSWORD))) 
            {
                System.out.println("\nWrong Password Try Again");
            } 
            else 
            {
                System.out.println("\nWelcome!");
                break;
            }
        }
    }
}

这是我尝试使用 switch 语句来“捕获”循环的每次迭代并执行操作的另一种尝试，但我不确定为什么它会无限循环:

import java.io.*;
import java.util.*;

public class Password2
{
    public static void main (String [] args)
    {
        final String PASSWORD = "Test";

        System.out.print("\nEnter Your Password: ");
        Scanner input = new Scanner(System.in);
        String inputPass = input.nextLine();

        do
        {
            for(int passAttempts = 0; passAttempts < 3; passAttempts++)
            {
                switch(passAttempts)
                {
                    case 0:
                        System.out.println("\nWrong password try again\t2 attempts remaining");
                        break;
                    case 1:
                        System.out.println("\nWrong password try again\t1 attempts remaining");
                        break;
                    case 2:
                        System.out.println("\nWrong password try again\t0 attempts remaining");
                        break;
                    default:
                        System.out.println("\nContact Help desk");
                        break;
                }  
            }    
        }
        while(!(inputPass.equals(PASSWORD)));
    }
}

我哪里出错了？

Answer 1

您可以这样做，或者不要在 while 语句中比较密码，而是在 if(password.equals(PASSWORD) 下方放置一个 break 语句，但既然您说过要避免它:

public static void main(String[] args) 
{
    final String PASSWORD = "Test";
    Scanner sc = new Scanner(System.in);
    int attempts = 3;
    String password = "";
    while (attempts-- > 0 && !PASSWORD.equals(password)) //compares and then decrements
    {
        System.out.print("Enter your password: ");
        password = sc.nextLine();
        if (password.equals(PASSWORD)) 
            System.out.println("Welcome");
        else 
            System.out.println("Incorrect. Number of attempts remaining: " + attempts);        
    }
}