Java又玩了？ (是/否)

Question

这个问题已经有答案了:

How to use this boolean in an if statement? (8 个回答)

已关闭 7 年前。

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，任何其他输入也是如此。逻辑看起来很好，但我在 replayCheck = input.next().charAt(0); 行上得到“分配的值从未被使用”所以我怀疑问题就在那里。

我是个小菜鸟。欢迎任何建议!

Answer 1

将“=”更改为“==”进行比较，您的代码可以正常工作:

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