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std::chrono::high_resolution_clock::now

STD::时间::高[医]分辨力[医]时钟::现在

static std::chrono::time_point now((since C++11)

返回表示当前时间点的时间点。

参数

%280%29

返回值

表示当前时间的时间点。

例外

noexcept规格:

noexcept

二次

#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::high_resolution_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::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"; } }

二次

可能的产出:

二次

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

二次

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