#include <iostream>
#include <vector>
#include <random>
#include <ctime>
#include <chrono>
#include <string>
#include <fstream>

using namespace std::chrono;


class LogDuration {
public:
    explicit LogDuration(const std::string& msg = "")
            : message(msg + ": ")
            , start(steady_clock::now())
    {
    }

    ~LogDuration() {
        auto finish = steady_clock::now();
        auto dur = finish - start;
        std::cerr << message
                  << duration_cast<milliseconds>(dur).count()
                  << " ms" << std::endl;
    }
private:
    std::string message;
    steady_clock::time_point start;
};

#define UNIQ_ID_IMPL(lineno) _a_local_var_##lineno
#define UNIQ_ID(lineno) UNIQ_ID_IMPL(lineno)

#define LOG_DURATION(message) \
  LogDuration UNIQ_ID(__LINE__){message};

template<typename T>
void print1(const std::vector<T> v)
{
    std::ofstream file("text1.txt");
    for (const auto i : v)
        file << i;
    std::cout << std::endl;
}

template<typename T>
void print2(const std::vector<T> v)
{
    std::ofstream file("text2.txt");
    for (const auto& i : v)
        file << i;
    std::cout << std::endl;
}

template<typename T>
void print3(const std::vector<T>& v)
{
    std::ofstream file("text3.txt");
    for (const auto i : v)
        file << i;
    std::cout << std::endl;
}

template<typename T>
void print4(const std::vector<T>& v)
{
    std::ofstream file("text4.txt");
    for (const auto& i : v)
        file << i;
    std::cout << std::endl;
}


int main ()
{
    std::mt19937 gen(time(0));
    std::uniform_int_distribution<> uid(0, 500);

    std::vector<std::string> v(100000);

    for (auto& str : v)
    {
        str.resize(uid(gen));
        for (auto& c : str)
            c = char(uid(gen));
    }


    LOG_DURATION("Output without &")
    {
        print1(v);
    }

    LOG_DURATION("Output with &i")
    {
        print2(v);
    }

    LOG_DURATION("Output with &v")
    {
        print3(v);
    }

    LOG_DURATION("Output with &v and &i")
    {
        print4(v);
    }

  return 0;
}