Question

我为电梯创建了一个登录系统，需要当前正常工作的身份验证。我遇到的问题是程序在成功登录后无法继续运行。登录失败将在3次尝试失败后终止程序;这也行得很好。我认为它与我的break;行或我的括号位置有关。我尝试过使用continue;，但这也不起作用。代码的下一部分在登录后不会运行，也没有给出错误。

这是我的代码;

static Scanner console = new Scanner(System.in);

public static void main(String[] args) {

    final int UserID = 5555; 
    final int Password = 1234;
    final int StudentNumber = 22334455;

    int EnteredUserID; 
    int EnteredPassword;
    int EnteredStudentNumber;
    for (int s = 0; s <= 3; s++) { 
        if (s < 3) { 
            System.out.println("Enter your UserID to access lift;"); 
            EnteredUserID = console.nextInt();
            System.out.println("Your UserID is ==> " + EnteredUserID);
            System.out.println("Enter your password to authenticate login;");
            EnteredPassword = console.nextInt();
            System.out.println("Password Entered is ==> " + EnteredPassword);
            System.out.println("Enter your student number to finalise login and authentication;");
            EnteredStudentNumber = console.nextInt();
            System.out.println("Student Number Entered is ==> " + EnteredStudentNumber);
            if (UserID == EnteredUserID && (Password == EnteredPassword) 
                    && (StudentNumber == EnteredStudentNumber)) {
                System.out.println("Athentication complete!");
                System.out.println("***Elevator access granted!***");
                System.out.println("Welcome..."); 
                break;

            } else {
                System.out.println("Wrong UserID, Password or Student Number. Please try again."); 
            }
        } else {
            System.out.println("3 incorrect enteries detected. Access Denied!"); 
        }
    }
}


    private int currentFloor;

    public Elevator() {
        currentFloor = 0;
    }

    public void selectFloor() {
        Scanner scnr = new Scanner(System.in);
        int newFloor;

        System.out.println("Enter your destination floor ==> ");
        newFloor = scnr.nextInt();
        if (newFloor > 7 || newFloor < 0) {
            System.out.println("Invalid floor entry");
        }

        else {  
            int direction = 0;
            if(currentFloor < newFloor){
                direction = 1; 
            } else if (currentFloor > newFloor) {
                direction = -1; ;
            } else {
                direction = 0; 
            }
            for (; currentFloor != newFloor; currentFloor += newFloor)
                System.out.println("..." + currentFloor);
                System.out.println("Elevator has arrived!");
        }
    }

    public void fireAlarm() {
        System.out.println("***FIRE ALARM*** Please exit the building safely.");


}

}

我可能遗漏了一些非常简单的东西，但似乎无法找到它。

Answer 1

你正在做的是你breaking离开了循环。这会将其发送出循环并返回到方法的其余部分，在这种情况下，该方法为空。你没有指示它做任何事情。我想你的意思是：

        if (UserID == EnteredUserID && (Password == EnteredPassword) 
                && (StudentNumber == EnteredStudentNumber)) {
            System.out.println("Athentication complete!");
            System.out.println("***Elevator access granted!***");
            System.out.println("Welcome...");
            Elevator a = new Elevator(); //actually do something
            Elevator.selectfloor();
            break;
        }

即假设Elevator是一个类。

Answer 2

三次失败后，for循环结束，因此方法返回并退出程序。成功登录后，您将退出for循环...方法返回并退出程序。

您希望在成功登录时发生什么？以及实现这一目标的代码在哪里？

程序在休息后无法继续运行;在循环中

2 个答案: