#include <vector>
#include <iostream>

template <typename T>
using matrix = std::vector<std::vector<T>>;

template <typename T>
matrix<T> make_matrix(size_t x, size_t y)
{
    return { x, typename matrix<T>::value_type(y) };
}

int main() {
    auto mat = make_matrix<char>(3, 5);
    for (auto& row : mat)
    {
        for (auto& cel : row)
            std::cout << (int) cel << " ";
        std::cout << "\n";
    }
}