Java ArrayIndexOutOfBoundsException(扫雷)

Question

我正在尝试制作一个简单的扫雷器，在 n*n 板上埋下 n*n/3 个地雷。地雷用*标记，空格用0标记。(它还不能作为游戏运行:我正在尝试制作扫雷的“答卷”)请注意，我还没有使用过任何有目的的方法。

我在第 23 行不断收到错误:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 15

我已经尝试了几个小时来解决这个问题，但似乎没有任何效果。谁能指出哪里出了问题以及我应该如何修复我的代码？谢谢。

import java.util.Scanner;
public class Minesweeper {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        char board[][] = new char [n][n]; // makes board of n*n
        int a, b;
        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[i].length; j++) {
                board[i][j] = '0';
            }
        }
        for (int i = 0; i < n * n / 3; i++) { // '*' is a mine
            a = (int)(Math.random() * (n - 1) + 1.0);
            b = (int)(Math.random() * (n - 1) + 1.0);
            board[a][b] = '*';
        }

        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[i].length; j++) {
                for (int k = i - 1; k <= i + 1 && k >= 0 && k <= n; k++) {
                    for (int l = j - 1; l <= j + 1 && l >= 0 && l <= n; l++) {
                        if (board[k][l] == '*' && !(k == i && l == j)) {
                            board[i][j] = (char)(Character.getNumericValue(board[i][j]) + 1);
                        }
                    }
                }
            }
        }

        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[i].length; j++) {
                System.out.println(board[i][j]);
            }
        }
    }

}

Answer 1

           for (int k = i - 1; k <= i + 1 && k >= 0 && k <= n; k++) {
                for (int l = j - 1; l <= j + 1 && l >= 0 && l <= n; l++) {

应该是 k < n 且 l < n。 n 已经超出边界。

还有

    for (int i = 0; i < n * n / 3; i++) { // '*' is a mine
        a = (int)(Math.random() * (n - 1) + 1.0);
        b = (int)(Math.random() * (n - 1) + 1.0);
        board[a][b] = '*';
    }

好像不对，我觉得应该是

    for (int i = 0; i < n * n / 3; i++) { // '*' is a mine
        a = (int)(Math.random() * n);
        b = (int)(Math.random() * n);
        board[a][b] = '*';
    }