java - 简单的 Java Bank Atm 登录循环错误

Question

第一次发帖，这里的人似乎很有帮助。我目前正在编写我的第二个简单银行 atm/帐户作业。我的用户密码登录代码没有执行以下操作。

<强>1。当在数组中找不到管脚时返回循环开始

<强>2。如果 pin 不正确则使程序停止

这里只是登录脚本的片段。问题在于 while (menuChoice==1){} 循环。

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

    boolean userLogin = false;          //Flag for user login authorization 
    boolean progOn=true;            //confirmation that program is still be running         

    int num = 0, i = 0;
    int Bal[] = {500, 250, 400, 700};
    String Names[] = {"Niall", "Sean", "John", "Connor"};
    String pin[] = {"1234", "2345", "3456", "4567"};
    String menu2 = "\n1. Deposit \n2. Withdrawal \n3. Balance \n4: Change pin \n5: Exit";
    String pinChoice = "", pinChange="";

    int sub = 0;            //To keep the subscript
    String startMenu = "";      //The entered choice for the Start menu as a string
    int menuChoice = 0;     //The entered choice for the menu as an int

    //--------------------
    //login script
    //--------------------
    while (progOn == true) {
        System.out.println("------------------------");
        System.out.println("Welcome! Please select an option...\n");
        System.out.println(">1. Login");
        System.out.println(">2. Quit");
        System.out.println("------------------------");

        startMenu = in.next();

        while (!startMenu.matches("[1-2]")) {       //If the user enters a non digit, give message and return
            System.out.println("\nError. Please enter a valid Menu option.\n");
            System.out.println(">1. Login");
            System.out.println(">2. Quit");

            System.out.print("Please select an option\n");          //Ask the user to choose again
            startMenu = in.next();
        }//end while loop

        menuChoice = Integer.parseInt(startMenu);   //Parse the string to an int

        while (menuChoice == 1) {           //While loop to carry out the users choice
            System.out.println("------------------------");
            System.out.println("Please enter your pin number: ");
            System.out.println("------------------------");
            pinChoice = in.next();

            while (!pinChoice.matches("\\d{4}")) {  // 4 numbers only message to the user, if number is shorter or longer than 4
                System.out.println("------------------------");
                System.out.println("Error, must be a 4 number pin only! Please retry:");
                System.out.println("------------------------");
                pinChoice = in.next();
            }

            for (i = 0; i < Names.length; i++) {
                //Check if PIN exists
                if (pinChoice.matches(pin[i])) {
                    userLogin = true;   //If the PIN exists (true) the user is brought to the main menu
                    System.out.println("------------------------");
                    System.out.println("Please select a option from the menu...");
                    sub = i;        //sub is the array number stored of that account
                }//end if PIN matches
            }


            if (userLogin == false) {   //If the PIN doesn't exist
                System.out.print("\nPin does not exist\n\n");   //Tell the user and bring them back to the main menu
            }//end if no user found

            break;

        }// end loop menuChoic == 1

        while (menuChoice == 2) {       //user chooses to Leave the program
            System.out.print("\nThank you, goodbye\n");
            System.exit(0);             //Exits the program
            break;
        }//end menuChoice==2

        //--------------------
        //end login script
        //--------------------
    }
}

我知道程序的其余部分运行良好。我就是拿不到这一小部分。

请记住，这是我在 Comp 的第一年。科学。我的讲师没有向我们展示任何面向对象的知识，因此他不会只向我们介绍基础知识。

感谢观看! :)

Answer 1

在循环中，你应该使用局部变量。你有一个全局变量

int i;    

尝试将循环中的 i 更改为 int ii

 for (int ii = 0; ii < Names.length; ii++) {
   //Check if PIN exists
   if (pinChoice.matches(pin[ii])) {
       userLogin = true;   //If the PIN exists (true) the user is brought to the main menu
       System.out.println("------------------------");
       System.out.println("Please select a option from the menu...");
       sub = ii;        //sub is the array number stored of that account
   }//end if PIN matches
 }