#include <algorithm>
#include <vector>


std::vector<int>  v(1000);
std::generate(v.begin(), v.end(), [n = 0] () mutable { return n++; });

static void StringCreation(benchmark::State& state) {
  // Code inside this loop is measured repeatedly
  for (auto _ : state) {
    std::string created_string("hello");
    // Make sure the variable is not optimized away by compiler
    benchmark::DoNotOptimize(created_string);
    std::for_each(begin(v), end(v), [](auto& i){ i += 2; });
  }
}
// Register the function as a benchmark
BENCHMARK(StringCreation);

static void StringCopy(benchmark::State& state) {
  // Code before the loop is not measured
  std::string x = "hello";
  for (auto _ : state) {
    std::string copy(x);
    transform(begin(v), end(v), begin(v), [](const auto& i){ return i + 2; });
  }
}
BENCHMARK(StringCopy);