Recursively mapping mines on a minesweeper board - c++

Question

I have been trying to make a minesweeper game where given coordinates for a cell it will recursively reveal adjacent cells until a cell adjacent to a bomb is found. I have a method that given coordinates x and y calculates how many mines are surrounding it.
// Counts how many mines are adjacent to a given coordinate cell if any
void board::mineCount(int x, int y) {
// North
if (y > 0) {
if (board[x][y - 1].hasMine) {
board[x][y].mineCount++;
}
}
// South
if (y < dimensions[1] - 1) {
if (board[x][y + 1].hasMine) {
board[x][y].mineCount++;
}
}
// East
if (x < dimensions[0] - 1) {
if (board[x + 1][y].hasMine) {
board[x][y].mineCount++;
}
}
// West
if (x > 0) {
if (board[x - 1][y].hasMine) {
board[x][y].mineCount++;
}
}
// North East
if (x < dimensions[0] - 1 && y > 0) {
if (board[x + 1][y - 1].hasMine) {
board[x][y].mineCount++;
}
}
// North West
if (x > 0 && y > 0) {
if (board[x - 1][y - 1].hasMine) {
board[x][y].mineCount++;
}
}
// South East
if (x < dimensions[0] - 1 && y < dimensions[1] - 1) {
if (board[x + 1][y + 1].hasMine) {
board[x][y].mineCount++;
}
}
// South West
if (x > 0 && y < dimensions[1] - 1) {
if (board[x - 1][y + 1].hasMine) {
board[x][y].mineCount++;
}
}
}
Each cell is a struct which has a mineCount field that gets incremented by 1 each time a mine is found adjacent to it. I am having trouble figuring out where my recursion logic would go. I tried doing something like:
// North
if (y > 0) {
if (board[x][y - 1].hasMine) {
board[x][y].mineCount++;
} else {
minecount(x, y-1);
}
}
for each position but to no avail. Any pointers would be appreciated.

Answer 1

The recursion shouldn't be a part of the code that performs the mine count itself. It should be part of the function that's responsible for revealing nearby tiles.
int get_adjacent_mine_count(point p) {
int mine_count = 0;
for(int i = -1; i <= 1; i++) {
for(int j = -1; j <= 1; j++) {
point this_point(p.x + i, p.y + j);
//is_inside_board checks to see if the point's coordinates are less than 0
//or greater than the board size
if(!is_inside_board(board, this_point)) continue;
//We ignore the center tile
if(i == 0 && j == 0) continue;
if(board(this_point).hasMine)
mine_count++;
}
}
return mine_count;
}
void reveal_tiles(point p) {
//We shouldn't throw if the recursion is correct
if(board(p).hasMine) throw Explosion("Stepped on a Mine!");
//Single call to previously defined function
int num_of_adjacent_mines = get_adjacent_mine_count(p);
//I'm assuming this gets initialized to -1 beforehand
board(p).revealed = num_of_adjacent_mines;
if(num_of_adjacent_mines == 0) {
for(int i = -1; i <= 1; i++) {
for(int j = -1; j <= 1; j++) {
point this_point(p.x + i, p.y + j);
if(!is_inside_board(board, this_point)) continue;
if(i == 0 && j == 0) continue;
if(board(this_point).revealed == -1)
reveal_tiles(this_point);
}
}
}
}
I'm going to strongly recommend you write a simple Matrix class to represent board, which my code implies you've done, because that's a much more robust solution than just trying to interact with a 2D array the C-style way you're doing it.