Fix array not properly being assigned

Question

I am trying to assign a specific part of an array a new value, but it doesn't seem to be inserting the new value into the array.

char matrix[20][8] = {/*160 * '#'*/};

void Draw() {
    system("CLS");
    cout << "Welcome to Primitive Pong v1.0!" << endl;
    for (int i = 0; i < 8; i++) {
        cout << endl;
        for (int j = 0; j < 20; j++) {
            cout << matrix[i][j] << " ";
        }
    }
}

while (gameOver == false) {
    matrix[10][4] = 'O';
    Draw();
    this_thread::sleep_for(chrono::milliseconds(1000));
}

I expect this to output a grid of 160 "#" with a "O" near the middle, but instead it just prints 160 "#". I am trying to make a game of console pong. I have tried using 'matrix[10][4] = {'O'};, but that does nothing different.

Your matrix has 20 rows 8 columns but your Draw function accesses 20 columns. — Ben Voigt
– Ben Voigt, Commented Jul 6, 2019 at 5:38
I stared at this code for like 20 minutes and didn't notice that lmao — Kellen Cole
– Kellen Cole, Commented Jul 6, 2019 at 5:48

6502 · Accepted Answer · 2019-07-06 06:04:59Z

4

The problem is that you declare matrix[20][8] but then you access it as if its dimensions are [8][20] instead.

The total is the same but the access doesn't work correctly and, unfortunately, C++ will not check about this kind of mistake. Changing the code to

        cout << matrix[j][i] << " ";

should make things work a you expect.

answered Jul 6, 2019 at 6:04

6502

115k17 gold badges177 silver badges277 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Fix array not properly being assigned

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related