在给出正确的输出之前，Java循环3次

Question

我正在申请一份政治或天文学方面的测验。

我的问题是，当你说“政治”或“天文学”时，它会再次要求你输入两次，然后才会给出"test“的期望输出。

代码如下：

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        do {
            if (getAnswer().equalsIgnoreCase("neither")) {
                System.out.println("Please enter \'astronomy\' or \'politics\'.");
            }
        getAnswer();
        }
        while(getAnswer().equalsIgnoreCase("neither"));
    System.out.println("test");
    }
    public static String getAnswer() {
        Scanner quizType = new Scanner(System.in);
        System.out.println("Would you like to be quizzed on politics or astronomy?");
        String typeAnswer = quizType.next();
        if (typeAnswer.equalsIgnoreCase("politics")) {
            return "politics";
        }
        else if (typeAnswer.equalsIgnoreCase("astronomy")) {
            return "astronomy";
        }
        else {
            return "neither";
        }
    }
}

有什么想法吗？

谢谢

Answer 1

不需要 getAnswer() 3次，只需getAnswer()到一个String变量，你就可以开始工作了。

如下所示：

public static void main(String[] args) {
        String answer = "";
        do {
            answer = getAnswer();
            if (answer.equalsIgnoreCase("neither")) {
                System.out.println("Please enter \'astronomy\' or \'politics\'.");
            }
        } while (answer.equalsIgnoreCase("neither"));
        System.out.println("test");
    }

    public static String getAnswer() {
        Scanner quizType = new Scanner(System.in);
        System.out.println("Would you like to be quizzed on politics or astronomy?");
        String typeAnswer = quizType.next();
        if (typeAnswer.equalsIgnoreCase("politics")) {
            return "politics";
        } else if (typeAnswer.equalsIgnoreCase("astronomy")) {
            return "astronomy";
        } else {
            return "neither";
        }
    }

Answer 2

如果你正在学习do-while，那么你只需要在do中提示即可。当前您正在调用getAnswer三次，这将强制重复提示。

以下是使用do-while解决此问题的快速方法

public static void main(String[] args) {
    List<String> validAnswers = Arrays.asList("neither","politics","astronomy");
    String answer;

    do {
        answer = promptForAnswer();
    } while(!validAnswers.contains(answer));

    System.out.println("test");
}

public static String promptForAnswer() {
    System.out.println("Would you like to be quizzed on politics or astronomy?");

    return new Scanner(System.in).next();
}

或者你可以使用while循环...

public static void main(String[] args) {
    List<String> validAnswers = Arrays.asList("neither","politics","astronomy");

    while(!validAnswers.contains(promptForAnswer())) {
        System.out.println("That was not a valid response, try again!");
    }

    System.out.println("test");
}

public static String promptForAnswer() {
    System.out.println("Would you like to be quizzed on politics or astronomy?");

    return new Scanner(System.in).next();
}