std::chrono::file_clock::now
提供: cppreference.com
< cpp | chrono | file clock
| static std::chrono::time_point<std::chrono::file_clock> now() noexcept; |
(C++11以上) | |
時の現在点を表す time point を返します。
[編集] 引数
(なし)
[編集] 戻り値
現在時刻を表す time point。
[編集] 例
Run this code
#include <iostream> #include <vector> #include <numeric> #include <chrono> volatile int sink; int main() { for (auto size = 1ull; size < 1000000000ull; size *= 100) { // record start time auto start = std::chrono::file_clock::now(); // do some work std::vector<int> v(size, 42); sink = std::accumulate(v.begin(), v.end(), 0u); // make sure it's a side effect // record end time auto end = std::chrono::file_clock::now(); std::chrono::duration<double> diff = end-start; std::cout << "Time to fill and iterate a vector of " << size << " ints : " << diff.count() << " s\n"; } }
出力例:
Time to fill and iterate a vector of 1 ints : 2.43e-07 s Time to fill and iterate a vector of 100 ints : 4.1e-07 s Time to fill and iterate a vector of 10000 ints : 2.519e-05 s Time to fill and iterate a vector of 1000000 ints : 0.00207669 s Time to fill and iterate a vector of 100000000 ints : 0.423087 s
