Assign C array to C++’s std::array? (std::array = T[U]) – no suitable constructor exists from “T [U]” to “std::array”

There is no conversion from plain array to std::array, but you can copy the elements from one to the other:

std::copy(std::begin(X), std::end(X), std::begin(Y));

Here’s a working example:

#include <iostream>
#include <array>
#include <algorithm>  // std::copy

int main() {
    int X[8] = {0,1,2,3,4,5,6,7};
    std::array<int,8> Y;
    std::copy(std::begin(X), std::end(X), std::begin(Y));
    for (int i: Y)
        std::cout << i << " ";
    std::cout << '\n';
    return 0;
}