Zero Initialized Array

std::vector<int> arr;
arr.resize(100'000'000);
std::fill(arr.begin(), arr.end(), 0);

# Only measure this part
for (auto i = 0u; i < arr.size(); ++i) {
  arr[i] = i;
}
^ This is Faster?
std::vector<int> arr;
arr.resize(100'000'000);

# Only measure this part
for (auto i = 0u; i < arr.size(); ++i) {
  arr[i] = i;
}
^ This is Faster?

* The benchmark is run under AMD Ryzen 9.

* For the full benchmark code, please refer here.

* For illustration purposes only, see FAQ for more details.