C# 停止递归

Question

So I have made a maze where '#' are walls and '.' are available coordinates to move to. I'm attempting to stop the recursion when it finds its way outside of the maze. So when either (x,y) is 12. This may be a simple fix.

This is my maze...

char[,] maze1 =
            // USE THIS
        { { '#', '#', '#', '#', '#', '#', '#', '#', '#', '#', '#', '#' },
        { '#', '.', '.', '.', '#', '.', '.', '.', '.', '.', '.', '#' },
        { '#', '.', '#', '.', '#', '.', '#', '#', '#', '#', '.', '#' },
        { '#', '#', '#', '.', '#', '.', '.', '.', '.', '#', '.', '#' },
        { '#', '.', '.', '.', '.', '#', '#', '#', '.', '#', '.', '.' },
        { '#', '#', '#', '#', '.', '#', '.', '#', '.', '#', '.', '#' },
        { '#', '.', '.', '#', '.', '#', '.', '#', '.', '#', '.', '#' },
        { '#', '#', '.', '#', '.', '#', '.', '#', '.', '#', '.', '#' },
        { '#', '.', '.', '.', '.', '.', '.', '.', '.', '#', '.', '#' },
        { '#', '#', '#', '#', '#', '#', '.', '#', '#', '#', '.', '#' },
        { '#', '.', '.', '.', '.', '.', '.', '#', '.', '.', '.', '#' },
        { '#', '#', '#', '#', '#', '#', '#', '#', '#', '#', '#', '#' } };

Here is my method...

private void mazeTraversal(int currentX, int currentY, char[,] maze)
    {
        /*************** ATTEMPT 1 ******************/

        // Checks if coordinates are inside the maze
        if (currentX <= 11 && currentY <= 11)
        {
            // Implement maze traversal recursive call
            //PrintOriginalMaze(maze, currentX, currentY);

            // If the coordinate is a '.' , continue(This is the base case)
            if ('.' == maze[currentX, currentY])
            {
                // Changes location to a X so you cant go back.
                maze[currentX, currentY] = 'X';

                // Implement maze traversal recursive call
                PrintOriginalMaze(maze, currentX, currentY);

                mazeTraversal(currentX, currentY + 1, maze);
                // maze[currentX, currentY] = 'X';

                mazeTraversal(currentX - 1, currentY, maze);
                //maze[currentX, currentY] = 'X';

                mazeTraversal(currentX + 1, currentY, maze);
                // maze[currentX, currentY] = 'X';

                mazeTraversal(currentX, currentY - 1, maze);
                //maze[currentX, currentY] = 'X';

            }

            if ('#' == maze[currentX, currentY])
            {
                Console.WriteLine("Hit a wall");
                Console.WriteLine();
            }
        }
    }

Answer 1

You really should put a "exit" node in the labyrinth. At [4][11] I think. Then it would be a simple check if you found the exit(node).

What you have here is the age old problem of gameboards: "How do I deal with stuff just outside the playfield?" and "What do I do if I am at a border and want to check all neighbouring cells?"

For the most part, you avoided that problem. You have a "border" of walls. Putting a non-enterable border around the gameboard is one of the solutions. The other would be dealing with all those Index checks. But personally I prefer accounting for a border.

Answer 2

If i understand your question, and you are trying to determine if the current x and y are outside the bounds of your maze ( array )

You could use Array.GetUpperBound(Int32)

Gets the index of the last element of the specified dimension in the array.

var maxX = maze1.GetUpperBound(0);
var maxY = maze1.GetUpperBound(1);

if (currentX > maxX || currentX < 0 || currentY > maxY || currentY < 0)
  return;

Stopping the recursion is just a matter of exiting the method consistently (on some state) to unwrap the call, ie using a return when your current xy is outside the bounds .