won() Doesn't Work Properly

Question

My won() function works properly when the board dimensions are 3 x 3. However, it doesn't work properly when the board dimensions are 4 x 4. What could possibly be wrong?

for (int i = 0; i < d; i++)
{   
    for (int j = 0; j < d; j++)
    {
        if ((i==(d-1)) && (j==(d-1)))
        {   
            if (board[i][j] != 0)
                return false;
        }
        else if (j > 0)
        {
            if (board[i][j] < board[i][j-1])
                return false;
        }
        else
        {
            if (board[i][j] < board[i-1][d-1])
                return false;
        }
    }
}
return true;

Answer 1

I'm not quite sure how that works with any size.

First time through the loop:

say d = 4
i = 0
j = 0

if 0 == 3  //no
else if 0 > 0  //no
else
   if board[0][0] < board[-1][3]  //board[-1][3] ?? is off the grid

Consider the winning position:

01 02 03 04
05 06 07 08
09 10 11 12
13 14 15

board[0][0] is 1  (i is 0, j is 0)
board[0][1] is 2  (i is 0, j is 1)
board[0][2] is 3  (i is 0, j is 2)
board[0][3] is 4  (i is 0, j is 3)
board[1][0] is 5  (i is 1, j is 0)
etc.

Notice how I'm just looping through i and then j? What's happening to the value? Can you think of an easy way to test whether your tiles are in order?

Brenda.