Java又玩了吗？ （Y / N）

Question

import java.util.Scanner;
public class PlayAgain {
public static void main(String[] args) {

    Scanner input = new Scanner(System.in);           
    boolean playing = true;
    char replayCheck;

    do { //start do-while
        System.out.print("Play again? (y/n): ");           
        boolean validInput = false;
        while (validInput = false){ //start while
            replayCheck = input.next().charAt(0);
            switch (replayCheck) { //start switch
                case 'y':
                case 'Y':
                    validInput = true;
                    playing = true;
                    break;
                case 'n':
                case 'N':
                    validInput = true;
                    playing = false;
                    break;
                default:
                    System.out.println("Invalid input! please enter (y/n)");
                    validInput = false;
                    break;
            } //end switch
        } //end while
    } while (playing = true); //end do-while     
    System.out.println("Thanks for playing!");
} //end main
} //end class

如果用户输入n/N程序再次播放，则任何其他输入也一样。逻辑似乎很好，但我得到了＃34;指定的值从未使用过＆＃34;与replayCheck = input.next().charAt(0);一致，所以我怀疑问题就在那里。

我有点像诺贝尔。欢迎任何建议！

Answer 1

改变＆＃39; =＆＃39;到＆＃39; ==＆＃39;为了比较，你的代码工作正常：

import java.util.Scanner;
public class PlayAgain {
public static void main(String[] args) {

    Scanner input = new Scanner(System.in);
    boolean playing = true;
    char replayCheck;

    do { //start do-while
        System.out.print("Play again? (y/n): ");
        boolean validInput = false;
        while (validInput == false){ //start while
            replayCheck = input.next().charAt(0);
            switch (replayCheck) { //start switch
                case 'y':
                case 'Y':
                    validInput = true;
                    playing = true;
                    break;
                case 'n':
                case 'N':
                    validInput = true;
                    playing = false;
                    break;
                default:
                    System.out.println("Invalid input! please enter (y/n)");
                    validInput = false;
                    break;
            } //end switch
        } //end while
    } while (playing == true); //end do-while
    System.out.println("Thanks for playing!");
} //end main
} //end class

Answer 2

检查需要：

while (validInput == false) {
    ....
}

否则，您会将false分配给validInput，从而导致false，从而退出循环。

在Java中，编写此类检查的惯用方法是：

while (!validInput) {
    ...
}

Answer 3

问题在于它应该是while循环 while (validInput == false) {}