std::chrono::high_resolution_clock::now
来自cppreference.com
< cpp | chrono | high resolution clock
| static std::chrono::time_point<std::chrono::high_resolution_clock> now() noexcept; |
(C++11 起) | |
返回表示当前时间的时间点。
参数
（无）
返回值
表示当前时间的时间点。
示例
运行此代码
#include <iostream> #include <vector> #include <numeric> #include <chrono> volatile int sink; int main() { for (auto size = 1ull; size < 1000000000ull; size *= 100) { // 记录开始时间 auto start = std::chrono::high_resolution_clock::now(); // 做一些工作 std::vector<int> v(size, 42); sink = std::accumulate(v.begin(), v.end(), 0u); // 确保其副效应 // 记录结束时间 auto end = std::chrono::high_resolution_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"; } }
可能的输出：
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