#include <string>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <iterator>
#include <algorithm>
#include <numeric>
#include <chrono>
using namespace std;

string const delim = ", ";

string join_auto(vector<string> const& v)
{
  string ret;
  if (! v.empty()) {
    ret = v[0];
    for (auto i = v.begin() + 1; i != v.end(); ++i) { ret += delim; ret += *i; }
  }
  return ret;
}

string join_foreach(vector<string> const& v)
{
  string ret;
  if (! v.empty()) {
    ret = v[0];
    for_each(v.begin() + 1, v.end(), [&](string const& s){ ret += delim; ret += s; });
  }
  return ret;
}

string join_rangefor(vector<string> const& v)
{
  string ret;
  for (auto const& s : v) { ret += s; ret += delim; }
  if (! v.empty()) { ret.resize(ret.size() - delim.size()); }
  return ret;
}

string join_sstream(vector<string> const& v)
{
  ostringstream ss;
  copy(v.begin(), v.end(), ostream_iterator<string>(ss, delim.c_str()));
  return ss.str();
}

string join_accum(vector<string> const& v)
{
  return accumulate(v.begin(), v.end(), string(),
    [](string const& a, string const& b) -> string { return a + delim + b; });
}

string join_accum_move(vector<string> const& v)
{
  return accumulate(v.begin(), v.end(), string(),
    [](string& a, string const& b) -> string { return move(a) + delim + b; });
}

template <string F(vector<string> const&)>
void test(int n, vector<string> const& v, string const& name)
{
  using namespace std::chrono;
  auto start = high_resolution_clock::now();

  for (int i = 0; i < n; ++i)
  {
    F(v);
  }
  
  auto ms = duration_cast<milliseconds>(high_resolution_clock::now() - start);
  cout << ms.count() << "ms\t-- " << name << endl;
}

#define TEST(N, V, F) (test<(F)>((N), (V), #F))

int main()
{
  vector<pair<int, int>> counts { {1000,100}, {1000,1000}, {1000,10000} };
  for (auto const& n : counts)
  {
    cout << endl << "Testing with " << n.first;
    cout << " vectors of " << n.second << " strings:" << endl;
    vector<string> v;
    v.insert(v.begin(), n.second, "foobar");
    TEST(n.first, v, join_auto);
    TEST(n.first, v, join_foreach);
    TEST(n.first, v, join_rangefor);
    TEST(n.first, v, join_sstream);
    TEST(n.first, v, join_accum);
    TEST(n.first, v, join_accum_move);
  }
}