如何搜索二维数组中的任何索引？

Question

So I'm making a program that takes in a 2D array of 5x5, and lists all the characters around any given index of the array. For example, if I input list[1][1], it will give the indexes: [0][0], [0][1], [0][2], [1][0], [1][2], [2][0], [2][1] ,[2][2].

I can print out all the letters around the indexes except for the ones on the edges such as index [0][0]. I can't seem to figure out how to get past that.

 private static void checkSurrounding(char[][] list, int x, int y) {
    for(int dx = -1; dx <= 1; dx++) {
        for(int dy = -1; dy <= 1; dy++) {
            if(!(dx == 0 && dy == 0)) {
                System.out.print(list[x + dx][y + dy]);
            }
        }
    } 
}

Answer 1

Your code is almost correct! You exclude the middle point here:

 private static void checkSurrounding(char[][] list, int x, int y) {
    for(int dx = -1; dx <= 1; dx++) {
        for(int dy = -1; dy <= 1; dy++) {
            if(!(dx == 0 && dy == 0)) {
                System.out.print(list[x + dx][y + dy]);
            }
        }
    } 
}

The only thing you miss is to avoid getting out of bounds. Just make sure that you do not get out of bounds and it should work impeccably:

 private static void checkSurrounding(char[][] list, int x, int y) {
    for(int dx = -1; dx <= 1; dx++) {
        if ((x + dx >= 0) && (x + dx < list.length)) {
            for(int dy = -1; dy <= 1; dy++) {
                if ((y + dy >= 0) && (y + yd < list[x + dx].length) && (!(dx == 0 && dy == 0))) {
                    System.out.print(list[x + dx][y + dy]);
                }
            }
        }
    } 
}