std::chrono::high_resolution_clock::now
From cppreference.com
< cpp | chrono | high resolution clock
static std::chrono::time_point<std::chrono::high_resolution_clock> now() noexcept; |
(since C++11) | |
Returns a time point representing the current point in time.
[edit] Parameters
(none)
[edit] Return value
A time point representing the current time.
[edit] Example
Run this code
#include <chrono> #include <cstddef> #include <iomanip> #include <iostream> #include <numeric> #include <vector> volatile int sink; void do_some_work(std::size_t size) { std::vector<int> v(size, 42); sink = std::accumulate(v.begin(), v.end(), 0); // make sure it is a side effect } int main() { std::cout << std::fixed << std::setprecision(9) << std::left; for (auto size{1ull}; size < 10'00'00'00'00ull; size *= 100) { const auto start = std::chrono::high_resolution_clock::now(); do_some_work(size); const auto end = std::chrono::high_resolution_clock::now(); const std::chrono::duration<double> diff = end - start; std::cout << "Time to fill and iterate a vector of " << std::setw(9) << size << " ints : " << diff << '\n'; } }
Possible output:
Time to fill and iterate a vector of 1 ints : 0.000006568s Time to fill and iterate a vector of 100 ints : 0.000002854s Time to fill and iterate a vector of 10000 ints : 0.000116290s Time to fill and iterate a vector of 1000000 ints : 0.011742752s Time to fill and iterate a vector of 100000000 ints : 0.505534949s