Trouble with recursion in minesweeper

[Angela Li]

This is my code for inspecting a cell in minesweeper, and it is not working as I had expected but I can't quite figure out what is wrong. Some help would be appreciated.

public boolean inspect(int x, int y) {
		if (board[x][y].getMined()) {
			board[x][y].setOpened(true);
			System.out.println("YOU LOSE");
			return false;
		} else if (board[x][y].getSymbol() != '0') {
			board[x][y].setOpened(true);
			return true;
		} else
			for (int xval = x - 1; xval <= x + 1; xval++) {
				for (int yval = y - 1; yval <= y + 1; yval++) {
					if (xval > 0 && yval > 0 && xval <= row && yval <= col) {
						if (board[xval][yval].getOpened()
								|| board[xval][yval].getFlagged()
								|| board[xval][yval].getMined()) {
						} else if (board[xval][yval].getSymbol() != '0') {
							board[xval][yval].setOpened(true);
						} else if (board[xval][yval].getSymbol() == '0') {
							board[xval][yval].setOpened(true);
							inspect(xval, yval);
						}
					}
				}
			}

		return true;
	}

[Tim Moores]

It would help to know what you expected this method to do, and how its actual behavior deviates from that.

[Angela Li]

So, I expected the method to open up just the cell (x,y) if it is next to a mine so its not zero. But if it is zero or no mines are adjacent to it then I expect it to recursively open the cells around it. But the method is failing to recursively open.

[Stephan van Hulst]

It looks like you are checking your loop variables wrongly. Shouldn't they be allowed to be equal to 0 as well? Anyway, you have a lot of clutter in that snippet of code. Here's a simpler version:

public boolean inspect(int x, int y) {
  Cell cell = board[x][y];
  cell.setOpened(true);
  
  if (cell.hasMine())
    return false;
    
  if (cell.getSymbol() != '0')
    return true;
    
  for (int i = x-1; i <= x+1; i++)
    for (int j = y-1; j <= y+1; j++) {
      if (i < 0 || i >= board.length ||
          j < 0 || j >= board[i].length)
        continue;
        
      Cell neighbour = board[i][j];
      if (!neighbour.isOpen())
        inspect(i, j);
    }
    
  return true;
}

[Angela Li]

thanks for making my code more concise, i was getting confused myself with all the if statements. It works now that I took your suggestion, thanks so much. I spent so long on this.