Getter returning 2d array in C++ - c++

Question

this is my first post on SO, even though i've spent some time already here.
I've got here a problem with a function returning a 2d array. I have defined a private 2d int array property int board[6][7] in my Game class, but i don't know how to create a public getter for this property.
These are relevant parts of my game.h:
#ifndef GAME_H
#define GAME_H
class Game
{
public:
static int const m_rows = 6;
static int const m_cols = 7;
Game();
int **getBoard();
private:
int m_board[m_rows][m_cols];
};
#endif // GAME_H
Now what I would like is something like this in game.cpp (cause I thought array name without brackets is a pointer to first element, obviously it doesn't work with 2d arrays) :
int **Game::getBoard()
{
return m_board;
}
So that i can put this for example in my main.cpp:
Game *game = new Game;
int board[Game::m_rows][Game::m_cols] = game->getBoard();
Can anybody help me, what should i put in my game.cpp ?
Thanks!

Answer 1

You cannot pass arrays by value into and out of functions. But there's various options.
(1) Use a std::array<type, size>
#include <array>
typedef std::array<int, m_cols> row_type;
typedef std::array<row_type, m_rows> array_type;
array_type& getBoard() {return m_board;}
const array_type& getBoard() const {return m_board;}
private:
array_type m_board;
(2) Use the correct pointer type.
int *getBoard() {return m_board;}
const int *getBoard() const {return m_board;}
private:
int m_board[m_rows][m_cols];
An int[][] has no pointers involved. It isn't a pointer to an array of pointers to arrays of integers, it's an array of an array of integers.
//row 1 //row2
[[int][int][int][int]][[int][int][int][int]]
Which means one int* points to all of them. To get to a row offset, you'd do something like this:
int& array_offset(int* array, int numcols, int rowoffset, int coloffset)
{return array[numcols*rowoffset+coloffset];}
int& offset2_3 = array_offset(obj.getBoard(), obj.m_cols, 2, 3);