Tic Tac Toe Win Checking Function

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

The error I get is:

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

What seems to be the problem?

Answer 1

[John D'Errico]

Your function has no arguments. How do you expect it to know what those variables are?

[Joseph Cheng]

what are the values of tttXArray for each marker? instead of a a long list of if-else statements for the horizontal/vertical wouldn't it be easier to and cleaner to check for the sum of a row and sum of columns? that would leave just 2 if statements for the diagonals which can be simplified as well.

[Thorsten]

Joseph is right. You can use something like

 function won = checkwin(A)
  won = any(all(A) | all(A, 2)' | all(diag(A)) | all(fliplr(diag(A))));

[Anas Abou Allaban]

So the values of tttXArray come from another function where the player chooses their spot.

    function [pXInputRow, pXInputCol] = pickXspot(playerInput)
  %This function is to take inputs from Player X
  global pXInputRow;
  global pXInputCol;
  %Set text for Roq/Col Prompt
  prompt = {'Row (1,2, or 3)', '(Col (1, 2, or 3)'};
  name = 'Player X Turn';

%Show prompt to input values
playerInput = inputdlg(prompt, name);
pXInputRow = str2num(playerInput{2});
pXInputCol = str2num(playerInput{1});

end

So I should take tttXArray as an input argument. However, I get

Undefined function or variable 'pXInputRow'.

Thanks for simplified if/else statement suggestion, definitely much cleaner.

[Anas Abou Allaban]

Forgot last line:

tttArray(pXInputRow, pXInputCol) = 1;

[Thorsten]

No. You should define

function won = checkwin(tttXArray)

and call using

 checkwin(tttXArray)

[Anas Abou Allaban]

So I realized my rather beginner mistake, I was not calling the function properly nor was I giving it any proper arguments. The checkwin function works good now, time to debug the rest of the code. Thanks Thorsten for the simplified checking algorithm!