//********************************************************
// The following code example is taken from the book
//  C++ Move Semantics - The Complete Guide
//  by Nicolai M. Josuttis (www.josuttis.com)
//  http://www.cppmove.com
//
// The code is licensed under a
//  Creative Commons Attribution 4.0 International License
//  http://creativecommons.org/licenses/by/4.0/
//********************************************************


#include <iostream>
#include <string>
#include <vector>
#include <chrono>

// string wrapper with move constructor:
struct Str
{
  std::string val;

  // ensure each string has 100 characters:
  Str()
   : val(100, 'a') {   // don't use braces here
  }

  // enable copying:
  Str(const Str&) = default;

  // enable moving (with and without noexcept):
  Str (Str&& s) NOEXCEPT
   : val{std::move(s.val)} {
  }
};

int main()
{
  // create vector of 1 Million wrapped strings:
  std::vector<Str> coll;
  coll.resize(1000000);

  // measure time to reallocate memory for all elements:
  auto t0 = std::chrono::steady_clock::now();
  coll.reserve(coll.capacity() + 1);
  auto t1 = std::chrono::steady_clock::now();

  std::chrono::duration<double, std::milli> d{t1 - t0};
  std::cout << d.count() << "ms\n";
}