`operator<<` overload for `std::array` and `std::vector`

pretty_print.hxx

#pragma once

#include <array>
#include <cmath>
#include <vector>
#include <iomanip>
#include <ostream>

using std::ostream;
using std::ios_base;
using std::round;
using std::setw;
using std::scientific;
using std::setprecision;

template <size_t N>
ostream& operator<<(ostream& out, std::array<double, N> arr) {
    ios_base::fmtflags original_flags{out.flags()};
    out << scientific << setprecision(4);
    out << "[" << setw(11) << arr[0];
    for (size_t i{1}; i < N; i++) {
        out << ", ";
        out << setw(11) << arr[i];
    }
    out << "]";
    out.flags(original_flags);
    return out;
}

template <typename T>    // Unused but why not
ostream& operator<<(ostream& out, std::vector<T> vec) {
    ios_base::fmtflags original_flags{out.flags()};
    out << "[" << vec[0];
    for (size_t i{1}; i < vec.size(); i++) {
        out << ", ";
        out << vec[i];
    }
    out << "]";
    out.flags(original_flags);
    return out;
}