java - 替换数组中的字符串并将其保留在内存中？

Question

所以我在完善我的程序时遇到了问题。该程序应该使用用户输入创建一个一维数组。然后它会创建一个像这样的“O”框..

N = 4

OOOO
OOOO
OOOO
OOOO

用户根据框输入坐标，“O”更改为“X”。该程序应该在选择坐标后重复自身，同时记住 X 的位置并将其包含在下一个循环中。

我尝试实现一个 while 循环，但似乎代码只是在数组上循环而不记住 X 的最后位置。

我如何更改代码，使其执行我需要执行的操作？

public static void makeArray(int M) {
    String input = "";
    boolean repeat = false;
    int N = InputNumber(input);
    String[] Board = new String[N];
    M = (int) Math.sqrt(N);
    String A = "O";
    String B = "X";

    System.out.println("Printing " + (M) + " x " + (M) + " board...");
    System.out.println("Done.");
    System.out.println();

    while (!repeat) {
        int X = Xvalue(M);
        int Y = Yvalue(M);

        int C = convertIndex(X, Y, M);

        System.out.println("Marking location " + X + "," + Y + ")");
        for (int i = 0; i < (Board.length); i++) {
            {
                Board[i] = A;
                if ((i % M == 0)) {
                    System.out.println();
                }
                if (i == C) {
                    Board[i] = Board[i].replace(A, B);
                }
                if (i == C && C == -1) {
                    repeat = true;
                }
            }
            System.out.print(Board[i]);
        }
        System.out.println();
    }
}

public static int convertIndex(int x, int y, int N) {

    int valX = (x - 1) * N;
    int valY = y;
    int targetIndex = valX + valY;

    return (targetIndex - 1);

}

public static int Xvalue(int M) {
    boolean repeat = false;
    int X = 0;
    while (!repeat) {

        System.out.print("Please enter the X-coordinate: ");
        String InputX = new Scanner(System.in).nextLine();
        X = Integer.parseInt(InputX);
        if (X > M) {
            System.out.println();
            System.out.println("Error, please enter a valid X Coordinate...");
            repeat = false;
        } else {
            repeat = true;
        }
    }
    return X;
}

public static int Yvalue(int M) {
    boolean repeat = false;
    int Y = 0;

    while (!repeat) {
        System.out.println();
        System.out.print("Please enter the Y-coordinate: ");
        String InputY = new Scanner(System.in).nextLine();
        Y = Integer.parseInt(InputY);
        if (Y > M) {
            System.out.println("Error, please enter a valid Y Coordinate...");
            repeat = false;
        } else {
            repeat = true;
        }
    }
    return Y;
}

Answer 1

循环的问题在于它在打印数组之前定义了数组中的每个元素:

while (!repeat) {
    //...
    for (int i = 0; i < (Board.length); i++) {
        {
            Board[i] = A; //Makes each element "O"
            //...
            if (i == C) { //Makes only the current cooridinate "X"
                Board[i] = Board[i].replace(A, B);
            }
            //...
        }
        System.out.print(Board[i]);
    }
}

要修复此问题以保留旧的 X，您需要删除赋值 Board[i] = A;。但您仍然需要初始化您的板，否则您将得到空字符串。所以你需要在循环之前添加一些东西，例如:

String[] Board = new String[N];
M = (int) Math.sqrt(N);
String A = "O";
String B = "X";
//initialize board
for (int i = 0; i < Board.length; i++)
    Board[i] = A;