Multidimensional Array Assignment

[thewitchking15]

I posted this in beginners and it generated no response so I figured I'd post it here
Hi guys, semi-noob here. I am making my third implementation of Tic Tac Toe with Artificial intelligence with this version being more streamlined and with less (Hopefully 0) globals. I am having trouble with the assignment and passing of multidimensional arrays. Specifically one, GameBoardInit[3][3], that contains a numeric representation of the game board

int main()//Game Loop
{
    using namespace std;
    //Variables
    int NumberOfPlayers;
    string PlayerOneName, PlayerTwoName;
    int Difficulty;
    char GameBoardState[3][3] = {'X', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '};
    int GameBoardInit[3][3] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
    int Move;

    //Game Initialization
    while (NumberOfPlayers == 0 || NumberOfPlayers > 2) //PseudoRecursive Menu Loop.
    {
        NumberOfPlayers = GameSetup();
    }
    PlayerOneName = PlayerNameInput(1, NumberOfPlayers); //Gather Player 1 Info
    if (NumberOfPlayers == 2) PlayerTwoName = PlayerNameInput(2, 0); //Gather Player 2 Info
    Difficulty = SetDifficulty();
    DisplayGameBoard(GameBoardState);
    //GameBoardInit[3][3] = InitializeGameBoard(GameBoardState);//This is the one I am having problems with
    Move = ComputerMoveMainLoop(GameBoardInit, Difficulty);
    cout << Move;

    return 0;
}

The Problematic Function:

int InitializeGameBoard(char GameBoardChar[][3])
{
    int x;
    int y;
    int GameBoardInit[3][3];
    for (x = 0; x < 3; x++)//Cycle Through Collumns
    {
        for (y = 0; y < 3; y++)//Cycle Through Rows
        {
            if (GameBoardChar[x][y] == 'X') GameBoardInit[x][y] = 1;
            else if (GameBoardChar[x][y] == 'O') GameBoardInit[x][y] = 2;
        }
    }
    return GameBoardInit[3][3];
}

Is there a way to alter GameboardInit and pass it back with another function. Running this code currently crashes the program. I'm using windows if that helps any.

[Duthomhas]

Remember that in C and C++, the range of indices in an array is 0 to N-1, where N is the number of elements in the array.

int xs[ 12 ];
xs[ 12 ] = -7; // hey, I'm indexing an element not in the array. 

With multidimensional arrays, the error is compounded.

Hope this helps.

[thewitchking15]

Duoas, You are correct, and I am aware of this. However, I am not assigning a value to one single point on the array, but reassigning values to the whole array. Is there a way to do this like I have set up?

[D80DSL3A]

You can't return an entire array like that. Try passing the 2nd array to the function as an argument:

void InitializeGameBoard(char GameBoardChar[][3], int GameBoardInit[][3] )
{
    int x;
    int y;
    for (x = 0; x < 3; x++)//Cycle Through Collumns
    {
        for (y = 0; y < 3; y++)//Cycle Through Rows
        {
            if (GameBoardChar[x][y] == 'X') GameBoardInit[x][y] = 1;
            else if (GameBoardChar[x][y] == 'O') GameBoardInit[x][y] = 2;
        }
    }
    return;// return nothing
}

Call it in main() like so:
InitializeGameBoard(GameBoardState, GameBoardInit);

[thewitchking15]

But then they would have to be Globals, right?

[Zhuge]

There's no need. Just like how you didn't need GameBoardState to be global to pass it, neither do you need GameBoardInit to be global.

[thewitchking15]

Yeah, but when I want to use them in other functions they won't work?

[Duthomhas]

The example given to you used the same names as your variables for arguments. But they aren't exactly the same thing.

void sum( int a[], unsigned n )
{
  int result = 0;
  for (unsigned x = 0; x < n; x++)
    result += a[ x ];
  return result;
}

int main()
{
  int primes[ 7 ] = { 2, 3, 5, 7, 11, 13, 17 };
  cout << "The sum of the first seven primes is " << sum( primes, 7 ) << "\n";

  int fibonaccis[] = { 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 };
  cout << "The sum of the first six fibonacci numbers is " << sum( fibonaccis, 6 ) << "\n";
}

The argument a could have been named "primes" or "fibonaccis" or anything else, because it doesn't matter. When you pass your array as argument, it gets a new name inside the function.

The new name could be the same as the old name, but that doesn't matter.


So, any time you have a function, pass the game board arrays as arguments the same way.

Hope this helps.

[D80DSL3A]

You would have to pass them to other functions too.

The use of global variables is often discouraged here, but I do use them sometimes for the "core" objects in a game eg. the gameboard, or other objects which the whole game centers on. I think it's reasonable in these cases.

[Duthomhas]

Agreed.