Tic-Tac-Toe Win checking function

Question

I'm writing a tic tac toe game and part of the 'coding rules' is that there should be a 'checkwin' function to see whether a player has won or not. I have defined two variables called 'tttXArray' and 'tttOArray' to see whether one player has gotten three in a row for horizontal, vertical, or diagonal inputs. This is the function with the tttXArray placed as an example:

function [won] = checkwin
%Check to see whether the game has been won or not
% Horizontal
    if (tttXArray(1,1) == tttXArray(1,2) && tttXArray(1,1) == tttXArray(1,3))
        won = 1;
    elseif (tttXArray(2,1) == tttXArray(2,2) && tttXArray(2,1) == tttXArray(2,3))
        won = 1;
    elseif (tttXArray(3,1) == tttXArray(3,2) && tttXArray(3,1) == tttXArray(3,3))
        won = 1;
    % Vertical
    elseif (tttXArray(1,1) == tttXArray(2,1) && tttXArray(1,1) == tttXArray(3,1)) 
        won = 1;
    elseif (tttXArray(1,2) == tttXArray(2,2) && tttXArray(1,2) == tttXArray(3,2)) 
        won = 1;
    elseif (tttXArray(1,3) == tttXArray(2,3) && tttXArray(1,3) == tttXArray(3,3)) 
        won = 1;
    % Diagonal
    elseif (tttXArray(1,1) == tttXArray(2,2) && tttXArray(1,1) == tttXArray(3,3))
        won = 1;
    elseif (tttXArray(1,3) == tttXArray(2,2) && tttXArray(1,3) == tttXArray(3,1))
        won = 1;
    end
end

Checkwin is part of a while loop:

while ~checkwin

    playerXTurn = 1;
    playerOTurn = 1;
    %Let Player X go first
    while playerXTurn
        pickXSpot %Prompt  Player
        disp('Test1')
        checktaken %Check taken location
        %If place is taken, prompt player to input again
        if checktaken == 1
            pickXspot
        else
            tttArray(pXInputRow, pXInputCol) = 1; %Set the position as taken
            tttXOArray(pXInputRow, pXInputCol) = 1; %Set the position for X(1)
            plot(pXInputRow, pXInputCol, 'x')
            hold on
            playerXTurn = 0;
        end
    end

    %Check if theres a win
    checkwin

    %Otherwise continue to Player O's turn
    while playerOTurn == 1
        pickOSpot %Prompt Player
        checktaken
        %If place is taken, prompt player to input again
        if checktaken == 1
            pickOspot
        else
            tttArray(pOInputRow, pOInputCol) = 1;%Set the position as taken
            tttXOArray(pOInputRow, pOInputCol) = 0;%Set the position for O(0)
            plot(pOInputRow, pOInputCol,'o')
            hold on
        end
    end  

    %Check win again
    checkwin
end

The error I get is:

Undefined function 'tttXArray' for input arguments of type 'double'.

What seems to be the problem?

You call tttXArray lots of times inside your function, but where do you DEFINE the function? The error says that you pass a double (2 arguments) to the function, but that the function definition (if it exists) does not allow the double as an argument. — wintvelt, Oct 02 '15 at 13:47
So much `if`statements. Just loop over the condition instead of explicitly writing out all possibilities, since that will take you a lot of time for larger systems — Adriaan, Oct 02 '15 at 13:48
`checkwin` needs a parameter passed to it... i.e. `function [won] = checkwin(tttXArray)` — Dan, Oct 02 '15 at 14:08
why does it smell like the code isnt yours ? the arrays `tttArray` and `tttXOArray` must be defined and __filled__, and the function `pickOspot` is unreferenced. — Abr001am, Oct 02 '15 at 15:03
I defined all these arrays as global arrays in a another function called boardplot and set them all to an array of 3x3 zeroes. They were defined like this: `global tttArray; tttArray = zeros(3);` — Anas Yousef, Oct 03 '15 at 11:46

score 0 · Answer 1 · answered Oct 03 '15 at 23:00

so I realized I was not calling the function properly nor was I giving it any arguments. Here is what I'm doing now

function [won] = checkwin(tttXArray)

I also simplified all the if/else statements as follows:

won = any(all(tttXArray) | all(tttXArray, 2)' | all(diag(tttXArray)) | all(fliplr(diag(tttXArray))));

Thanks for the tips!

Tic-Tac-Toe Win checking function

1 Answers1