CS50 AP Game of Fifteen

Question

I'm currently getting an error for "make sure game is winnable" but my program works with ./fifteen 3 < ~cs50/unit3/3x3.txt

Here is my error log:

:) fifteen.c exists.
:) fifteen.c compiles.
:) 3x3 board: init initializes board correctly
:) 3x3 board: catches moving 8 an illegal move
:) 3x3 board: catches moving 1 as a legal move
:) 3x3 board: move blank up twice
:) 3x3 board: move blank left twice
:) 3x3 board: move blank left then right
:) 3x3 board: move blank up then down
:) 3x3 board: move up-up-left-down-down-left-up-up-right-down-down-right
:) 3x3 board: make sure none of 2, 4, 5, 6, 7, 8 move tile
:) 3x3 board: move blank left (tile 1) then up (tile 4), then try to move tiles 1, 2, 6, 8
:( 3x3 board: make sure game is winnable
    expected "Tile to move:", not "\x1b[2J\x1b[0;0..."
:( 4x4 board: make sure game is winnable
    timed out while waiting for program to exit

This is my code:

// Initializes the game's board with tiles numbered 1 through d*d - 1
// (i.e., fills 2D array with values but does not actually print them)
void init(void)
{
    int num = (d * d) - 1;
    for (int i = 0, w = d; i < w; i++)
    {
        for (int ii = 0, ww = d; ii < ww; ii++)
        {
            board[i][ii] = num;
            num--;
            //printf("%i ", board[i][ii]); // For Testing
        }
        //printf("\n"); // For Testing
    }
    if (d == 4 || d == 6 || d == 8)
    {
        int a = board[d - 1][d - 2];
        int b = board[d - 1][d - 3];
        board[d - 1][d - 2] = b;
        board[d - 1][d - 3] = a;
    }
}

// Prints the board in its current state
void draw(void)
{
    for (int i = 0, z = d; i < z; i++)
    {
        for (int f = 0, zz = d; f < zz; f++)
        {
            if (board[i][f] == 0)
            {
                printf("%2c", '_');
            }
            else if (board[i][f] > 9 )
            {
                printf("%i ", board[i][f]);
            }
            else if (board[i][f] == 9 || board[i][f] < 9)
            {
                printf("%2i", board[i][f]);
            }

        }
        printf("\n");
    }
    // TODO
}

// If tile borders empty space, moves tile and returns true, else returns false
bool move(int tile)
{
    for (int i = 0, z = d; i < z; i++)
    {
        for (int ii = 0, zz = d; ii < zz; ii++)
        {
            if (tile == board[i][ii])
            {
                // Testing + YouTube Link
                //printf("%i\n", board[i][ii]);
                //printf("%i\n", board[i - 1][ii]);
                //printf("%i\n", board[i][ii - 1]);
                //printf("%i\n", board[i + 1][ii]);
                //printf("%i\n", board[i][ii + 1]);
                //printf("%i\n", d);
                // https://youtu.be/Rx_FJb3vr9U?t=369
                if (i + 1 != d)
                {
                    if (board[i + 1][ii] == 0)
                    {
                        int f = board[i + 1][ii];
                        int z = board[i][ii];
                        board[i + 1][ii] = z;
                        board[i][ii] = f;
                        return true;
                    }
                }
                //printf("%i\n", i - 1);
                if ((i - 1) > -1)
                {
                    if (board[i - 1][ii] == 0)
                    {
                        int f = board[i - 1][ii];
                        int z = board[i][ii];
                        board[i - 1][ii] = z;
                        board[i][ii] = f;
                        return true;
                    }
                }
                if (ii + 1 != d)
                {
                    if (board[i][ii + 1] == 0)
                    {
                        int f = board[i][ii + 1];
                        int z = board[i][ii];
                        board[i][ii + 1] = z;
                        board[i][ii] = f;
                        return true;
                    }
                }
                if ((ii - 1) > -1)
                {
                    if (board[i][ii - 1] == 0)
                    {
                        int f = board[i][ii - 1];
                        int z = board[i][ii];
                        board[i][ii - 1] = z;
                        board[i][ii] = f;
                        return true;
                    }
                }
            }
        }
    }
    return false;
}

// Returns true if game is won (i.e., board is in winning configuration), else false
bool won(void)
{
    int checker[d][d];
    int max = 1;
    int correct = 0;
    for (int i = 0, z = d; i < z; i++)
    {
        for (int ii = 0, zz = d; ii < zz; ii++)
        {
            checker[i][ii] = max;
            if (checker[i][ii] == ((d * d) - 1))
            {
                checker[i][ii] = 0;
            }
            max++;
        }
    }

    for (int i = 0, z = d; i < z; i++)
    {
        for (int ii = 0, zz = d; ii < zz; ii++)
        {
            if (checker[i][ii] == board[i][ii])
            {
                correct++;
            }
        }
    }

    if (correct == (d*d) - 1)
    {
        return true;
    }

    // TODO
    return false;
}

Thanks in Advance

Answer 1

The won() function won't return a true win. Look at the following code:

for (int i = 0, z = d; i < z; i++)
{
    for (int ii = 0, zz = d; ii < zz; ii++)
    {
        if (checker[i][ii] == board[i][ii])
        {
            correct++;
        }
    }
}

if (correct == (d*d) - 1)
{
    return true;
}

Now, say that d=3. The loop will increment correct to 9. The test checks whether correct is 8. Thus, it'll never find a true win. Remember, d*d - 1 is the number of non-zero or non-blank tiles, not the total number of spaces in the matrix.

Hmmm.... how did you get a win notification when you tested your code? I'm sure that you didn't just run check50 to do the testing, right?

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