Blank space expansion in text-based Minesweeper clone in Java

Question

I'm making a text-based Minesweeper clone in Java when an issue came up. I'm on the part where if you click a black space, it should reveal all of the blank spaces around that blank space and all blank spaces around that blank space, etc.

Code I have so far:

  public void exposeAround(){
    //Row = inputRow and Column = inputColumn
    for(int row = Row-1; row < Row+1; row++){
        for(int col = Column-1; col < Column+1; col++){
            if((row < 0) || (row > 8) || (col < 0) || (col < 8)){
                continue;
            } else{
                if(mines[row][col] == '.'){
                    board[row][col] = mines[row][col];
                    System.out.println("Test");
                    exposeAround();
                } else{
                    board[row][col] = mines[row][col];
                }
            }   
        }
    }
}

It doesn't throw any errors, but it doesn't do anything after this method is run, even after I run printBoard(); method

If you have any questions about other sections of my code, let me know. I have tried to find to find this answer, but the only things I can find are for a GUI-based Minesweeper

EDIT: Thanks everyone for help, I have solved my problem.

You probably also want `row <= Row+1` and `col <= Column+1` or you will only be exposing a 2x2 square, not a 3x3 square. — AJNeufeld, Jun 01 '18 at 01:28
Thank you so much! I edited those two things, but now it's throwing the Stack Overflow error from the infinite loop of recursion. Do you have any ideas on how I would fix this? — Zach Mcgregor, Jun 01 '18 at 01:31
The stacktrace will tell you where your recursion is out of control. Check those lines and fix the bug. — Hovercraft Full Of Eels, Jun 01 '18 at 01:32
The only line it says to fix is 303 which is the line with the exposeAround(): itself. I'm very nooby, I'm sorry if I'm asking very obvious things. — Zach Mcgregor, Jun 01 '18 at 01:34
If `Row` and `Column` don't change, you're going to keep doing the same thing repeatedly. — shmosel, Jun 01 '18 at 01:39

score -1 · Accepted Answer · answered Jun 01 '18 at 01:39

-1

You can use a simple floodfill algorithm to open up the empty spaces.

It will look something like this:

public void exposeAround(int x1, int y1){
    //if position (x1, y1) is a bomb or number
    //    return
    //if outOfBounds(x1, y1)
    //    return
    //open up location (x1, y1)
    //exposeAround(x1-1, y1)    - flood north
    //exposeAround(x1+1, y1)    - flood south
    //exposeAround(x1-1, y1-1)  - flood west
    //exposeAround(x1-1, y1+1)  - flood east
}

So it will "flood" all 4 directions. 1 direction at a time. When it hits a boundary (bomb, number, bounds of your 2D array), it backtracks to the last good position to continue the "flooding" process.

answered Jun 01 '18 at 01:39

user3437460

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I get a stack oveflow error – Zach Mcgregor Jun 04 '18 at 01:27
If your map size is too big like several hundred for width and height, that may happen. If not, make sure your boundary checks and base case is right. – user3437460 Jun 04 '18 at 11:37
So I implemented it, and it throws stackoverflow because it goes north, then south, then north, etc. How would you suppose I do this? – Zach Mcgregor Jun 04 '18 at 17:09
@ZachMcgregor It could use an "if already exposed, return" check at the top. That prevents revisiting previously exposed cells unnecessarily. – rbwhitaker Nov 06 '22 at 01:25

Blank space expansion in text-based Minesweeper clone in Java

1 Answers1