C++時間計測用コード

gistfile1.cpp

#include <chrono>
#include <utility>

template <class F, class ...Args>
std::chrono::system_clock::duration take_time(F&& f, Args&&... args) {
    namespace chrono = std::chrono;

    auto const begin = chrono::system_clock::now();
    f(std::forward<Args>(args)...);
    auto const end = chrono::system_clock::now();
    return end - begin;
}

#include <iostream>
#include <thread>

int main() {
    auto const time = take_time([] (int millis){
        std::chrono::milliseconds n(millis);
        std::this_thread::sleep_for(n);
    }, 5);
    std::cout << "time: " << std::chrono::duration_cast<std::chrono::milliseconds>(time).count() << " ms" << std::endl;
    return 0;
}