Create Minesweeper Like Game

I create this board with my code:

 1 2 3 4 5
1x x x x x 
2x x x x x
3x k x x x
4x x x k x
5x x x x x

I want to replace the board above with the board below, that is all the 'k'='*' and any values surrounding k have a counter.

   1 2 3 4 5
  10 0 0 0 0
  21 1 1 0 0
  31 k 2 1 1
  41 1 2 k 1
  50 0 1 1 1

How would I go about doing this?

[Walter Roberson]

I do not understand about 'k'='*', and it is not clear why the x became 0 in places that are not surrounding k.

[Image Analyst]

k is where a bomb resides. The other numbers are the number of 8-connected bombs that are next to that location. For example, row 3, column 3 is next to 2 bombs, so it's a 2. Row 3, column 4 is next to only one k, so it has a value of 1. Same as in the minesweeper game.

Answer 1

[Image Analyst]

Just use conv2() to count the bombs:

gameBoard = [...
  '0' '0' '0' '0' '0'
'1' '1' '1' '0' '0'
'1' 'k' '2' '1' '1'
'1' '1' '2' 'k' '1'
'0' '0' '1' '1' '1']
% Find the bombs.
bombLocations = gameBoard == 'k'
% Sum up the bombs in a surrounding 3x3 window around each pixel.
nearbyBombs = conv2(double(bombLocations), ones(3), 'same')
% Create a new board that is characters and instead of numbers.
newBoard = num2str(nearbyBombs, '%1d')
% Replace the bomb locations with the letter k.
newBoard(bombLocations) = 'k'

You'll see:

gameBoard =
00000
11100
1k211
112k1
00111
bombLocations =
     0     0     0     0     0
     0     0     0     0     0
     0     1     0     0     0
     0     0     0     1     0
     0     0     0     0     0
nearbyBombs =
     0     0     0     0     0
     1     1     1     0     0
     1     1     2     1     1
     1     1     2     1     1
     0     0     1     1     1
newBoard =
00000
11100
11211
11211
00111
newBoard =
00000
11100
1k211
112k1
00111

Answer 2

[Guillaume]

Please, use valid matlab syntax in your question, so we don't have to guess if the input is a cell array, a char array, or something else, and whether the spaces and headers are embedded in the matrix or not

Possibly:

in = ['xxxxx';
      'xxxxx';
      'xkxxx';
      'xxxkx';
      'xxxxx'];
%step 1: convert the input matrix into an array of 0 and 1, 1 where k is present
%if your input matrix is a different format, you'll have to figure how to do it on your own
inaslogical = in == 'k';
%step2: convolve the array of 0 and 1 with an array of 1:
out = conv2(double(inaslogical), ones(3), 'same')

[Krish Desai]

Cell array, spaces and headers are embedded I believe

function board = makeboard(size)
board = cell(size+1,size+1);
 % initialize the board
 for i=1:size+1
     for j=1:size+1
         if i==1
             if j<=size
                 board{i,j+1} = j;
                 board{j+1,i} = j;
             end
         elseif j==1

           elseif rand < 1/5
               board{i,j}='k';
           else 
               board{i,j}= 'x';
           end

       end  
   end
  end

[Guillaume]

Note: don't use the name size for a variable as you won't be able to use the extremely useful size function.

A more efficient way to generate your board:

function board = makeboard(boardsize)
   symbols = 'xk';
   playarea = num2cell(symbols(1 + (rand(boardsize) < 1/5)));
   header = num2cell(1:boardsize);
   board = [{[]}, header; header', playarea];
end

The gist of my answer (and IA's answer) still stands. You need to convert your play area into a logical array, where 1 stands for a mine. Then convolve with a square of 1 to get the number of neighbours.

With the given format:

ismine = cell2mat(board(2:end, 2:end)) == 'k';
neighbourcount = conv2(double(ismine), ones(3), 'same');
neighbourcount = num2cell(neighbourcount);
neighbourcount(ismine) = {'k'};
newboard = board;
newboard(2:end, 2:end) = neighbourcount;