问输入字符串中的C++ 3x3棋盘打印

EN

/* Gameboard should look like this when input is "1 1 4 2 1 4 2 3 5":
=============
|   | 1 2 3 |
-------------
| 1 | 1 1 4 |
| 2 | 2 1 4 |
| 3 | 2 3 5 |
=============
*/


#include <iostream>
#include <vector>
#include <string>
#include <sstream>

using namespace std;
using Board = std::vector<vector<int>>;

const unsigned int BOARD_SIDE = 3;
const unsigned char EMPTY = ' ';

void initBoard(Board& board) { // start questions + vector formation

    while (true) {
            cout << "Select start (R for random, I for input): ";
            string start;
            cin >> start;
            if (start == "i" or start == "I") {
                cout << "Input: ";
                string input = "";
                cin.ignore();
                getline(cin, input);

                istringstream is { input };
                vector<vector<int>> board(3, vector<int>(3)); // board is now 2D vector including 9 user input values

                for (auto& row : board)
                {
                    for(auto& column : row)
                    {
                        is >> column;
                    }
                }
                    for(const auto& row : board)
                    {
                        for (const auto column : row)
                        {
                            cout << column << " ";
                        }
                            cout << "\n";
                    }
                break;
                }
      }
}

void printBoard(const Board& board)
{
    // prints a board vector whose elements are vectors
    cout << "=============" << endl;
    cout << "|   | 1 2 3 |" << endl;
    cout << "-------------" << endl;
    for(unsigned int row = 0; row < BOARD_SIDE; ++row)
    {
        cout << "| " << row + 1 << " | ";
        for(unsigned int column = 0; column < BOARD_SIDE; ++column)
        {
            if(board.at(row).at(column) == 0)
            {
                cout << EMPTY << " ";
            }
            else
            {
                cout << board.at(row).at(column) << " ";
            }
        }
        cout << "|" << endl;
    }
    cout << "=================" << endl;
}

int main()
{
    Board board;
    initBoard(board);
    printBoard(board);
}

/* But it looks like this:
1 1 4 
2 1 4 
2 3 5 
=============
|   | 1 2 3 |
-------------
*/