密码、密码和密码的toWriting程序

Question

我试图创建一个程序，将提示用户输入正确的密码。第三次输入密码不正确时，程序应向用户询问PIN，如果用户仍未能正确输入PUK 3次尝试，程序现在应打印SIM阻塞。

我想我得用循环，但我不知道怎么做。我只是个新手。

import java.util.Scanner;
import java.io.*;
    public class PinPUK {
    public static void main(String[] a) {
    Scanner keyboard = new Scanner(System.in);
    System.out.print("Enter Pin Code: ");
    int choice  = keyboard.nextInt();
    if (choice == 123) {
        System.out.println("Welcome!");    
        }
    else {
        System.out.println("Password is incorrect! Try again!"); // This is the 1st time the wrong password has been entered.
    }                                                           // 2 more and the program should ask for the PIN 3 times if incorrectly entered, and program should ask the PUK 3 times if it is incorrect, the program should now print SIM BLOCKED.
    }
}

Answer 1

这可以通过使用以下代码片段来完成：

int count = 0;
while(count<3) {
    if (choice == 123) {
        System.out.println("Welcome!"); 
        break;   //break from the loop
    }
    else {
        System.out.println("Password is incorrect! Try again!");
    }
    count++;
}

if(count == 3) {
     System.out.println("SIM BLOCKED");
}

Answer 2

public class PinPUK {
    public static void main(String[] a) {
    Scanner keyboard = new Scanner(System.in);
    System.out.print("Enter Pin Code: ");
    int tries = 0;
    boolean correctPin = false;
    while(!correctPin) {
        //It is better to scan the next line and parse the integer
        int choice  = Integer.parseInt(keyboard.nextLine());
        if (choice == 123) {
           System.out.println("Welcome!"); 
           correctPin = true;   
        }
        else if (tries < 3{
            System.out.println("Password is incorrect! Try again!"); 
       }    
       else if (tries >= 3)
          System.out.println("SIM blocked");
       }
   }
}