java - Do/while 循环未正确执行

Question

我确信我错过了一些简单的东西，但我无法让我的 do while 循环正确执行。我希望它第一次运行并继续运行，直到用户输入 q。它当前执行一次，然后循环返回以询问要访问哪个帐户，然后什么都不做。任何帮助或为我指明正确的方向以便我可以修复它将不胜感激。

public class Crawford_Driver
{

    public static void main(String[] args)
    {
        Scanner keyboard = new Scanner(System.in);
        double input1;
        String accountChoice;
        String accountActivity;
        RegularAccount regAcct = new RegularAccount(0, .5);
        SavingsAccount savAcct = new SavingsAccount(0, .5);


        do{
            System.out.println("What account would you like to access(regular or savings)?" );
            accountChoice = keyboard.nextLine();

            if(accountChoice.equalsIgnoreCase("regular"))

                System.out.println("What action do you wish to perform(deposit, withdraw or monthly process)? ");
            accountActivity = keyboard.nextLine();

            if (accountActivity.equalsIgnoreCase("deposit"))
                {
                    System.out.println("How much would you like to deposit?");
                    input1= keyboard.nextDouble();
                    regAcct.deposit(input1);
                    System.out.println("Your balance is " + regAcct.getBalance() );
                }
            else if (accountActivity.equalsIgnoreCase("withdraw"))
                {
                    System.out.println("How much would you like to withdraw?");
                    input1= keyboard.nextDouble();
                    regAcct.withdraw(input1);
                    System.out.println("Your balance is "+ regAcct.getBalance());
                }
            else if (accountActivity.equalsIgnoreCase("monthly process"))
                {
                    regAcct.monthlyProcess();
                }
            else {
                if (accountChoice.equalsIgnoreCase("savings"))

                    if (accountActivity.equalsIgnoreCase("deposit"))
                        {
                            System.out.println("How much would you like to deposit?");
                            input1= keyboard.nextDouble();
                            savAcct.deposit(input1);
                            System.out.println("Your balance is " + savAcct.getBalance() );
                        }

                if (accountActivity.equalsIgnoreCase("withdraw"))

                    System.out.println("How much would you like to withdraw?");
                input1= keyboard.nextDouble();
                savAcct.withdraw(input1);
                System.out.println("Your balance is "+ savAcct.getBalance());

            }
        }while (!accountChoice.equalsIgnoreCase("Q"));

    }
}

Answer 1

此语句后缺少一组大括号:

if(accountChoice.equalsIgnoreCase("regular"))

...以及此声明:

 if (accountActivity.equalsIgnoreCase("withdraw"))

Java(以及 C 和 C++)的默认行为是仅执行 if、for 或之后的下行while 语句(如果省略大括号)。

完成后，您的语句应如下所示:

if(accountChoice.equalsIgnoreCase("regular")) {
    System.out.println("What action do you wish to perform(deposit, withdraw or monthly process)? ");
    accountActivity = keyboard.nextLine();
    // Rest of code that concerns activity with a "regular" account
}