Making a Tic Tac Toe Board Using Vectors-CodePudding

I'm just confused on where to start like how this actually draws a board using a 2d vector. I haven't edited any code and the code below is what is needed. It's unfinished code with several other functions I had to delete so I can just focus on creating the board first. How would I approach with creating this board with just a 3x3 of dashes?

How would I actually print out the 3x3 so it looks like this:

- - -
- - -
- - -

I'm thinking of something like:

// 2D display of board contents
void displayBoard(vector<vector<char>>& board) {
    // Your code here
    for (int i = 0; i < nRows; i  ) {
        
    }
}

But am not too sure how to continue it and print it out.

// Tic-tac-toe board - user plays against computer; displays board after each move
#include <iostream>
#include <vector>

using namespace std;

const int nRows = 3;
const int nCols = 3;

// 2D display of board contents
void displayBoard(vector<vector<char>>& board) {
    // Your code here


}

// Game loop
int main() {
    vector<vector<char>> board{ {'-', '-', '-'}, {'-', '-', '-'}, {'-', '-', '-'}};
    displayBoard(board);
    
}

CodePudding user response：

Each vector knows its own size(), so your display function can look something like this:

// 2D display of board contents
void displayBoard(const vector<vector<char>>& board) {
    for (size_t i = 0; i < board.size(); i  ) {
        for (size_t j = 0; j < board[i].size(); j  ) {
            cout << board[i][j] << ' ';
        }
        cout << endl;
    }
}

Or simpler:

// 2D display of board contents
void displayBoard(vector<vector<char>>& board) {
    for (const auto &vec : board) {
        for (auto ch : vec) {
            cout << ch << ' ';
        }
        cout << endl;
    }
}

CodePudding user response：

For your question, what does

vector<vector<char>> board{ {'-', '-', '-'}, {'-', '-', '-'}, {'-', '-', '-'}};

do? It initializes the board, a vector of vectors, using list initialization. Each {'-', '-', '-'} is a single vector. Three of these vectors in the list provides the "vector of vectors" dimensionality.

           {'-', '-', '-'}
position     0    1    2    for each inner vector

            { {'-', '-', '-'}, {'-', '-', '-'}, {'-', '-', '-'}};
              |_____________|  |_____________|  |_____________|
                     ^                ^                ^
position             0                1                2          for the outer vector

So, when accessing elements, the first index chooses the vector, the second index chooses the element within that vector:

{ {'-', '-', '-'}, {'-', '-', '-'}, {'-', '-', '-'}};
    ^                     ^                     ^
    |                     |                     |
board[0][0]               |                     |
                      board[1][1]               |
                                            board[2][2]

The other answer shows you how to print.