Function minmax

source/matplot/util/common.cpp:198–205

    }

    std::pair<double, double> minmax(const std::vector<double> &x) {
        if (x.empty()) {
            return std::make_pair(min(x), max(x));
        } else {
            auto [min_it, max_it] = std::minmax_element(x.begin(), x.end());
            return std::make_pair(*min_it, *max_it);
        }
    }

    double mean(const std::vector<double> &x) {
        double sum = 0;