Description : Copies n elements starting in the ranged passed, to another range beginning at passed argument.
Example:
std::vector<int> origin {1, 2, 3};
std::vector<int> destination;
// Will copy 2 values starting at origin.begin, to destination
std::copy_n(origin.begin(), 2, std::back_inserter(destination));
// destination is now {1, 2}
for (auto value : destination) {
std::cout << value << " ";
}