java - 如何修复 java.lang.arrayindexoutofboundsexception : 0?

Question

我是 java 的新手。谁能帮我解决错误 arrayindexoutofboundsexception。

public class Minesweeper { 
   public static void main(String[] args) { 

      int M = Integer.parseInt(args[0]);
      int N = Integer.parseInt(args[1]);
      double p = Double.parseDouble(args[2]);

      // game grid is [1..M][1..N], border is used to handle boundary cases
      boolean[][] bombs = new boolean[M+2][N+2];
      for (int i = 1; i <= M; i++)
         for (int j = 1; j <= N; j++)
            bombs[i][j] = (Math.random() < p);

      // print game
      for (int i = 1; i <= M; i++) {
         for (int j = 1; j <= N; j++)
            if (bombs[i][j]) System.out.print("* ");
            else             System.out.print(". ");
         System.out.println();
      }

      // sol[i][j] = # bombs adjacent to cell (i, j)
      int[][] sol = new int[M+2][N+2];
      for (int i = 1; i <= M; i++)
         for (int j = 1; j <= N; j++)
            // (ii, jj) indexes neighboring cells
            for (int ii = i - 1; ii <= i + 1; ii++)
               for (int jj = j - 1; jj <= j + 1; jj++)
                  if (bombs[ii][jj]) sol[i][j]++;

      // print solution
      System.out.println();
      for (int i = 1; i <= M; i++) {
         for (int j = 1; j <= N; j++)
            if (bombs[i][j]) System.out.print("* ");
            else             System.out.print(sol[i][j] + " ");
         System.out.println();
      }

   }
}

这里是异常(exception):

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at Minesweeper.main(Minesweeper.java:5) 

Answer 1

可能如索引 0 所述的两件事(参见第一种情况):

1. 您没有向主类传递参数。

2. 数组索引总是从 0 而不是 1 开始。因此您可能需要更改其中之一:

   • 你的循环从 0 开始并检查 i < M 或 N
   • 您使用数组索引作为 i - 1 而不是 i。

你得到 ArrayIndexOutOfBoundException 的原因是假设你在一个数组中有 2 个元素。它将如下所示:

a[0] = 1;
a[1] = 2;

当你循环使用 i = 1; i<=2 您正在访问:

a[1] - which is perfect
a[2] - which was not expected?