java Do While循环被卡住

Question

代码是一个Tic-Tac-Toe游戏（正在进行中）。当我运行代码时，它询问X的位置号，然后停止。它与while循环有关，因为当我在没有它的情况下运行它时，它工作得很好。然而，我需要循环将X设置为false，这样它就变成了O

import java.util.Scanner;
class TicTacToe


{
public static void main(String[] args)

{
    Scanner scan = new Scanner(System.in);
    int XInput, OInput;
    boolean IfGameOver;
    String []board = {"1","2","3","4","5","6","7","8","9"};
    IfGameOver = false;
    boolean Xturn, Oturn;
    Xturn = true;
    Oturn = false;

    System.out.print("Welcome to Tic-Tac-Toe!\n\n");
do
    {

        {
         System.out.println(" " + board[0] + board[1] + board[2]);
         System.out.println(" " + board[3] + board[4] + board[5]);
         System.out.println(" " + board[6] + board[7] + board[8]);
        }
             if (Xturn)
             System.out.println("It is X's turn, position number?");
             if (Oturn)
             System.out.println("It is O's turn, position number?");

            do
                {
                try
                {
                XInput = scan.nextInt();
                board[XInput-1] = "X";
                Oturn= true;
                Xturn = false;
                }
                catch (NumberFormatException e)
                {
                    System.out.println("Invalid input. Please enter a position number");
                    XInput = scan.nextInt();
                }
                }while(Xturn = true);
            do
                {
                try
                {
                OInput = scan.nextInt();
                board[OInput-1] = "X";
                Oturn = false;
                Xturn = true;
                }
                catch (NumberFormatException e)
                {
                    System.out.println("Invalid input. Please enter a position number");
                    OInput = scan.nextInt();
                }
                }while (Oturn = true);

    } while (!IfGameOver);
}
}

Answer 1

问题可能出在这一行：

            }while(Xturn = true);

这不是一个比较。=运算符是赋值。这会将值true分配给Xturn，然后继续循环，因为分配的结果始终是分配的值

为了进行比较，可以使用==。但由于Xturn是一个布尔值，您可以简单地编写：

            }while(Xturn);

Answer 2

改变

}while(Xturn = true);
...
}while (Oturn = true);

到

}while(Xturn);
...
}while (Oturn);

Xturn = true是一个赋值，不会检查Xturn是否为真。为此，必须使用Xturn == true或简单Xturn。这同样适用于Oturn

另外，如TAsk所述，您需要IfGameOver的值在循环内变为true，以便代码退出外部do while循环

Answer 3

你有很多问题。如前所述，您的while语句中没有使用相等检查，但其他问题会覆盖此问题。在X的回合之后，但在O的回合的do-while循环之前，您正在将Oturn设置为true。因此，您将在X输入之后立即进入Oturn do循环。这应该会把它清理干净

import java.util.Scanner;
class TicTacToe

{
public static void main(String[] args)

{
    Scanner scan = new Scanner(System.in);
    int Input;
    boolean IfGameOver;
    String []board = {"1","2","3","4","5","6","7","8","9"};
    IfGameOver = false;
    boolean Xturn = true;

    System.out.print("Welcome to Tic-Tac-Toe!\n\n");
do
    {

        {
         System.out.println(" " + board[0] + board[1] + board[2]);
         System.out.println(" " + board[3] + board[4] + board[5]);
         System.out.println(" " + board[6] + board[7] + board[8]);
        }
             if (Xturn)
             System.out.println("It is X's turn, position number?");
             else
             System.out.println("It is O's turn, position number?");

             Input = -1;
            do
                {
                try
                {
                Input = scan.nextInt();
                board[Input-1] = (Xturn?"X":"O");
                Xturn = !Xturn;
                }
                catch (Exception e)
                {
                    System.out.println("Invalid input. Please enter a valid position number");
                }
                }while(Input==-1);
    } while (!IfGameOver);
}
}