Matlab Reversi 'valid move' check - matlab

Question

Having issues with my move checker currently, it seems that the failsafe I put in my code to make it not look outside the bounds of the matrix isn't working, any suggestions?
There is also the issue that it doesn't seem to be working (i.e. I am still able to place pieces wherever I want!). The code I use earlier up is listed below as well
code:
function legal = legalMove()
d_l = [0, -1];
d_r = [0, 1];
d_u = [-1, 0];
d_d = [1, 0];
d_ul = [-1, -1];
d_ur = [-1, 1];
d_dl = [1, -1];
d_dr = [1, 1];
directions = {'d_l' 'd_ul' 'd_u' 'd_ur' 'd_r' 'd_dr' 'd_d' 'd_dl'};
valid_moves = zeros(8,8);
for ci = 1:8
for cj = 1:8
if game_state(ci,cj) == 0 %check element = 0
for count = 1:8
d = eval( directions{count} );
ti = ci+d(1);
tj = cj+d(2);
% Check if out of the board
if (ti > 8 || ti < 1) || (tj > 8 || tj < 1)
break
else
% Number of enemy pieces you went over
cnt = 0;
selected = game_state(ti, tj);
% Move while going over enemy pieces
while selected == player_number * -1
ti = ti + d(1);
tj = tj + d(2);
selected = game_state(ti, tj);
% Check if out of the board
if (ti > 8 || ti < 1) || (tj > 8 || tj < 1)
break
else
end
% Count pieces you went over
cnt = cnt + 1;
end
end
% Check if you moved over enemy pieces & whether you landed on your piece
if selected == player_number
valid_moves(ti,tj) = 1;
else
end
end
else
end
end
end
if ~isempty(valid_moves)
legal = 1;
else
legal = 0;
end
end
Error returned when done # boundries:
Attempted to access game_state(0,7); index must be a positive integer or
logical.
Error in umpire/legalMove (line 217)
selected = game_state(ti, tj);
Error in umpire/buttonPress (line 85)
legal = legalMove();
other piece:
function buttonPress(hObject, eventdata)
ended = game_is_over();
if ended == 1;
setAllInactive();
winner = calc_winner();
if winner == -1;
set(stat_text,'string','Winner is White! Restart?')
elseif winner == 1;
set(stat_text,'string','Winner is Black! Restart?')
else
set(stat_text,'string','Game is a tie! Restart?')
end
else
end
legal = legalMove();
if legal ~= 1;
set(stat_text,'Illegal move! Try again')
return
else
end
game_state(get(hObject,'userdata')) = player_number;
drawScreen();
player_number = player_number * -1;
end

Answer 1

In the second place where you assign variable selected (near the end of the function legalMove), you have out-of-board check in the wrong place.
Here's a fixed version
% ...
% Number of enemy pieces you went over
cnt = 0;
selected = game_state(ti, tj);
% Move while going over enemy pieces
while selected == player_number * -1
ti = ti + d(1);
tj = tj + d(2);
% Check if out of the board
if (ti > 8 || ti < 1) || (tj > 8 || tj < 1)
break
else
end
selected = game_state(ti, tj);
% Count pieces you went over
cnt = cnt + 1;
end
end
% Check if you moved over enemy pieces & whether you landed on your piece
if selected == player_number
valid_moves(ti,tj) = 1;
else
end
end