while循环在Java中不起作用

Question

我试图让这个问题在用户输入'Y'一遍又一遍地问。 然后停止并返回Event.displayFinalResults(); 当用户输入'N'

我现在正在连续循环。 我错过了一些东西或我的布局错了。 任何帮助都会很棒。

            System.out.println("Is there anymore amounts you want to add?(Y/N): ");
            Scanner keyboard = new Scanner(System.in);
            char choice = keyboard.next().charAt(0);
            choice = Character.toUpperCase(choice);
            if(choice == 'Y')
            {
                do
                {
                    System.out.println("Is there anymore amounts you want to add?(Y/N): ");
                    choice = keyboard.next().charAt(0);
                    choice = Character.toUpperCase(choice);

                    readValidateAmountType();
                    readValidateAmount(); 
                }
                while(choice =='Y');

            }
            else
            {
                Event.displayFinalResults();
            }

再次感谢。

Answer 1

您的程序会询问“是/否”问题，然后如果您回答“是”，则会进入一个循环，该循环首先询问相同的问题，然后再询问金额值。

您可能需要先询问金额值， 然后再问是/否问题。

如果用户回答“否”，则循环将退出（在询问另外一个金额值之后），但不会执行Event.displayFinalResults() 。 删除else子句，以便Event.displayFinalResults()是否输入if语句。

System.out.println("Is there anymore amounts you want to add?(Y/N): ");
Scanner keyboard = new Scanner(System.in);
char choice = keyboard.next().charAt(0);
choice = Character.toUpperCase(choice);
if (choice == 'Y')
{
    do
    {
        readValidateAmountType();
        readValidateAmount(); 

        System.out.println("Is there anymore amounts you want to add?(Y/N): ");
        choice = keyboard.next().charAt(0);
        choice = Character.toUpperCase(choice);
    }
    while(choice =='Y');
}
Event.displayFinalResults();

Answer 2

您可以使用break;执行此操作break; 如下：

do {
    System.out.println("Is there anymore amounts you want to add?(Y/N): ");
    choice = keyboard.next().charAt(0);
    choice = Character.toUpperCase(choice);
    if (choice !='Y') {
        break;
    }

    readValidateAmountType();
    readValidateAmount(); 
} while(true);

Event.displayFinalResults();

Answer 3

我看到的一个问题是，您的while循环位于if语句内部。 一旦退出while循环，就不会在else块中运行代码，因为if条件已经为真。

因此，请尝试删除else块。 一旦while循环退出，这将确保Event.displayFinalResults方法被调用。

     System.out.println("Is there anymore amounts you want to add?(Y/N): ");
        Scanner keyboard = new Scanner(System.in);
        char choice = keyboard.next().charAt(0);
        choice = Character.toUpperCase(choice);

if(choice == 'Y')
        {
            do
            {
                System.out.println("Is there anymore amounts you want to add?(Y/N): ");
                choice = keyboard.next().charAt(0);
                choice = Character.toUpperCase(choice);

                readValidateAmountType();
                readValidateAmount(); 
            }
            while(choice =='Y');

        }

        Event.displayFinalResults();

Answer 4

代码清晰，紧凑：

Scanner keyboard = new Scanner(System.in);
char choice;
do {
   System.out.println("Is there anymore amounts you want to add?(Y/N): ");
   choice = keyboard.next().charAt(0);
   choice = Character.toUpperCase(choice);
   if(choice == 'Y') {
      readValidateAmountType();
      readValidateAmount(); 
   }
} while(choice == 'Y');     
Event.displayFinalResults();   

Answer 5

尝试以下方法：

    public void answering(char answer){
        if(answer == 'Y' || answer == 'y'){
            System.out.println("Answering");
        } else if(answer == 'N' || answer == 'n'){
            System.out.println("Not answering");
    }

如果要询问，请调用此方法，而不是循环执行...