Passing an array to a function to display a tic-tac-toe board

Question

I am trying to create a tic-tac-toe game for a homework project, but I am stuck in not knowing how to pass an array. Currently, I have this:

Prototype:

void displayBoard(char);

Variables:

const int COLS = 3;
const int ROWS = 3;
char board[ROWS][COLS] = {'*', '*', '*', '*', '*', '*', '*', '*', '*'};

Function call:

displayBoard(board);

Function:

void displayBoard(char board)
{
    //DISPLAYBOARD displayBoard shows the current tic-tac-toe board
    //along with proper spacing

    cout << "---------------------" << endl << endl;
    cout << "     |     |     " << endl;
    cout << "  " << board[0][0] << "  |  " << board[0][1] << "  |  " << board[0][2] << endl;
    cout << "_____|_____|_____" << endl;
    cout << "     |     |     " << endl;
    cout << "  " << board[1][0] << "  |  " << board[1][1] << "  |  " << board[1][2] << endl;
    cout << "_____|_____|_____" << endl;
    cout << "     |     |     " << endl;
    cout << "  " << board[2][0] << "  |  " << board[2][1] << "  |  " << board[2][2] << endl;
    cout << "     |     |     " << endl;

}

I have tried several variations of passing the multidimensional array to the function displayBoard but I constantly get errors such as this one:

'void displayBoard(char)' cannot convert argument 1 from 'char[3][3]' to 'char' and if I leave the parenthesis () blank I also get an error saying 'board is not initialized' which it isn't, and I don't want to use a global variable.

Answer 1

Prototype should be the unintuitive:

void displayBoard(const char (&board)[ROWS][COLS]);

Using std::array<std::array<char, 3u>, 3u> would have more intuitive syntax.

Answer 2

You can use templates for the displayBoard method if you need to display boards of differents size:

template <int SizeX, int SizeY>
void displayBoard(const char (&board)[SizeX][SizeY])
{
    cout << "---------------------" << endl << endl;
    cout << "     |     |     " << endl;
    cout << "  " << board[0][0] << "  |  " << board[0][1] << "  |  " << board[0][2] << endl;
    cout << "_____|_____|_____" << endl;
    cout << "     |     |     " << endl;
    cout << "  " << board[1][0] << "  |  " << board[1][1] << "  |  " << board[1][2] << endl;
    cout << "_____|_____|_____" << endl;
    cout << "     |     |     " << endl;
    cout << "  " << board[2][0] << "  |  " << board[2][1] << "  |  " << board[2][2] << endl;
    cout << "     |     |     " << endl;

}

But be careful and always check you're accessing existing indexes in your array