Terminating a game of tic tac toe if two entries are entered in the same cell

As the title suggests, i am finishing up making a game of tic tac toe , and want to write some code at the end that will terminae/end the game if the players try and put more than one X or o in each space. This is what I have currently .

TTCboard = zeros(3,3);

% for creating the standard tic-tac-toe board in green

figure

plot([0 3],[-1 -1], 'g','linewidth',1);% creates top horizontal line in board

hold on

plot([2 2],[0 -3], 'g','linewidth',1)% creates right-most vertical line

plot([0 3],[-2 -2], 'g','linewidth',1)% creates bottom horizontal line

plot([1 1],[0 -3], 'g','linewidth',1)% creates left-most vertical line

axis off % keeps the X & y-axis off, creating a better looking natural board

hold off% ensures later commands are added to existing board

xticks([0 1 2 3]); yticks([0 1 2 3]);

xticklabels([]); yticklabels([]);

player = 'X' % designates the first player as X

while true % when it is player x's turn,

fprintf('%s click to place a piece\n', player); % creates X in the cell clicked on

[x, y] = ginput(1);

x = floor(x)+0.43 ;

y = floor(y)+0.5;

text(x,y,player, 'horizontalalignment', 'center', "FontSize",24);% gives specific parameters to the X on the board

xticks([0 1 2 3]); yticks([0 1 2 3]);

xticklabels([]); yticklabels([]);

player2 = 'O' % Designates the 2nd players turn

while true

fprintf('%s click to place a piece\n', player2);

[x, y] = ginput(1);

x = floor(x)+0.43 ;

y = floor(y)+0.5;

text(x,y,player2, 'horizontalalignment', 'center', "FontSize",24);

break;

end

end

[John Chilleri]

One possibility is to create an additional 3x3 matrix of zeros, and whenever an X or O is added, change the corresponding entry to 1. Then implement a simple check before placing Xs and Os that ensures the matrix entry is 0 (meaning available).

Answer 1

[Bob Thompson]

John has a pretty good idea with that.

If you put in a logic check and a loop, you don't even need to actually quit the game, just tell the player to pick an open spot.

Sample below, but beware that I have not tested it yet. Also, note that P1 has squares marked as 1, and P2 has squares marked as 2. I imagine that will be useful for determining who owns which squares and if somebody wins.

while true % when it is player x's turn,
    fprintf('%s click to place a piece\n', player); % creates X in the cell clicked on
    [x, y] = ginput(1);
    
    
    x = floor(x)+0.5 ;
    y = floor(y)+0.5;
    while TTCboard(x+0.5,-(y-0.5)) ~= 0;
        disp('Please pick an open square')
        [x, y] = ginput(1);
        x = floor(x)+0.5;
        y = floor(y)+0.5;
    end
    text(x,y,player, 'horizontalalignment', 'center', 'FontSize',24);% gives specific parameters to the X on the board
    % Close space for later use
    TTCboard(x+0.5,-(y-0.5)) = 1;
    
    xticks([0 1 2 3]); yticks([0 1 2 3]);
    xticklabels([]); yticklabels([]);
    

    
    player2 = 'O' % Designates the 2nd players turn
    while true
        fprintf('%s click to place a piece\n', player2);
        [x, y] = ginput(1);
        
        x = floor(x)+0.5;
        y = floor(y)+0.5;
        
        while TTCboard(x+0.5,-(y-0.5)) ~= 0;
            disp('Please pick an open square')
            [x, y] = ginput(1);
            x = floor(x)+0.5;
            y = floor(y)+0.5;
        end
        text(x,y,player2, 'horizontalalignment', 'center', 'FontSize',24);
        % Close space for later use
        TTCboard(x+0.5,-(y-0.5)) = 2;
        
        break;
    end
end

[Nathan Ross]

That seems like it would work looking at it, but when running it , there is an issue in where past the first input it no longer accepts any inputs at all

[Bob Thompson]

Really? I took exactly what I put down and didn't have any issues with it. Did you make other adjustments to it? I don't think I changed anything outside of what I posted.

[Nathan Ross]

I looked a little closer and noticed I had a small error, it works as it should now. That pretty much sums up the project . Thank you for all the help.