简单搜索中坐标的遍历

八个方向：

for (int dx = -1; dx <= 1; dx++) {
	for (int dy = -1; dy <= 1; dy++) {
		int nx = x + dx;
		int ny = y + dy;
	}
}

四个方向：

int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
for (int i = 0; i < 4; i++) {
	int nx = x + dx[i];
	int ny = y + dy[i];
}