如果他们让用户获得默认值，我正在尝试让我的开关盒再次循环答案

【问题标题】：I am trying to make my switch case loop back again if they get the user gets the default如果他们让用户获得默认值，我正在尝试让我的开关盒再次循环
【发布时间】：2020-12-06 19:22:42
【问题描述】：

我找不到可以使用的循环将其带回到 switch 案例的开头并重复，直到用户使用其中一个选项回答，任何帮助都会很棒！谢谢。（我也尝试过使用有人建议的 do-while 循环，但它似乎是默认的垃圾邮件。）（（我留在代码中））

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);


    System.out.println("    Welcome To The Choices Game...    ");
    System.out.println("Please enter your name: ");

    String playerName = input.nextLine();

    System.out.println("What is " + playerName + "'s" + " favorite pet?");
    System.out.println("a. Dog \nb. Cat");

    //Choice of choosing a dog or a cat
    String pet = input.next();
    do {


        switch (pet.charAt(0)) {
            case 'a' -> {
                System.out.println("What is your dog's name? ");
                String dogsName = input.next();
                System.out.println("Your Character's Name is: " + playerName + "\nYour Pet's Name is: " + dogsName);
                break;
            }
            case 'b' -> {
                System.out.println("What is your cat's name? ");
                String catsName = input.next();
                System.out.println("Character Name: " + playerName + "\nPet Name: " + catsName);
                break;
            }
            default -> System.out.println("That is not a valid option. Please choose again.");
        }

    } while (pet.charAt(0) != 'a' && pet.charAt(0) != 'b');

    input.close();

}

【问题讨论】：

好的，那么当你尝试你拥有的代码时出了什么问题？
每当我输入除 "a" 或 "b" 之外的另一个 char 或 int 时，它都会进入堆栈溢出，打印出“这不是一个有效的选项。请重新选择。”
而您期望会发生什么？我假设，再次提示用户输入。现在，仔细查看代码。您的代码中应该向用户询问"a" 或"b" 输入的部分是什么？这种情况会发生多少次？应该发生多少次？是在循环内，还是在循环外？应该在循环内还是循环外？
阅读ericlippert.com/2014/03/05/how-to-debug-small-programs 了解调试代码的技巧。
这能回答你的问题吗？ I am trying to make my switch case loop back again if they get the default

标签： java loops switch-statement

【解决方案1】：

您需要在 do 循环中获取 Cat/Dog（选项 a 或选项 b）的输入，以便在输入错误后代码可以要求更新输入。如下：

public static void main(String[] args) {

        Scanner input = new Scanner(System.in);

        System.out.println("    Welcome To The Choices Game...    ");
        System.out.println("Please enter your name: ");

        String playerName = input.nextLine();

        System.out.println("What is " + playerName + "'s" + " favorite pet?");
        System.out.println("a. Dog \nb. Cat");

        // Here is change in code
        String pet = null;
        do {
            // Choice of choosing a dog or a cat
            // Here is change in code
            pet = input.next();
            switch (pet.charAt(0)) {
            case 'a': {
                System.out.println("What is your dog's name? ");
                String dogsName = input.next();
                System.out.println("Your Character's Name is: " + playerName + "\nYour Pet's Name is: " + dogsName);
                break;
            }
            case 'b': {
                System.out.println("What is your cat's name? ");
                String catsName = input.next();
                System.out.println("Character Name: " + playerName + "\nPet Name: " + catsName);
                break;
            }
            default: {
                System.out.println("That is not a valid option. Please choose again.");
            }
            }

        } while (pet.charAt(0) != 'a' && pet.charAt(0) != 'b');

        input.close();

    }

【讨论】：