#include <iostream>
#include <cmath>
#include <vector>
#include <chrono>   

// templated alias to vector<>
template <typename T>
using vec = std::vector<T>;

struct MyThing{  
  int idat;
  vec<double> x;
  MyThing(int idat_, vec<double> x_) noexcept : idat{idat_},x{x_}{}
};

int main(){
  using clock = std::chrono::steady_clock;
  using std::chrono::milliseconds, std::chrono::duration_cast;
  const int N=1000000;
  auto t0 = clock::now();
  std::vector<MyThing> v;
  for (auto i=0;i<N;++i){
    v.push_back(MyThing(i,vec<double>{1.0,2.0,3.0,4.0,5.0,6.0}));     
  }
  auto t1 = clock::now();
  auto d = duration_cast<milliseconds>(t1-t0);	      
  std::cout <<"vector push_back took: "<<d.count() << " ms\n";
  
  std::vector<MyThing> w;
  t0 = clock::now();
  for (auto i=0;i<N;++i){
    w.emplace_back(i,vec<double>{1.0,2.0,3.0,4.0,5.0,6.0});
  }
  t1 = clock::now();
  d = duration_cast<milliseconds>(t1-t0);	
  std::cout <<"vector emplace_back took: "<<d.count() << " ms\n";
}