A matrix with array elements in c++

Question

I happened to need an n by n matrix, each of its elements is an integer array of length m. I was wondering what is the efficient method to create such matrix. By the way, I don't want to use the vectors here; I am interested to do this using c++ arrays. Furthermore, how I would be able to change the element of such matrix after creating one. Thank you for your time.

Answer 1

Using C-style arrays:

int arr [n][n][m];

Using C++ arrays:

std::array<std::array<std::array<int,n>,n>,m> arr;

Answer 2

You can define your own matrix type with C++ arrays (needs C++14):

template <unsigned N, unsigned M, typename T = int>
using Matrix = std::array<std::array<std::array<T, N>, N>, M>;

And, to use it:

Matrix<10, 3> mat1;           // T = int
Matrix<10, 3, unsigned> mat2; // T = unsigned