История изменений

template<int n, int m>
constexpr int sum_2d_array(const int (&arr)[n][m])
{
    int s = 0;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            s += arr[i][j];
    return s;
}

int main()
{
    constexpr int arr[3][2] = { 1, 2, 3, 4, 5, 6, };
    static_assert(sum_2d_array(arr) == 21);
}