C++ sadece saat nasıl alınır?

#include <iostream>

#include <chrono>

#include <ctime>   

int main()

{

    auto start = std::chrono::system_clock::now();

    // Some computation here

    auto end = std::chrono::system_clock::now();

    std::chrono::duration<double> elapsed_seconds = end-start;

    std::time_t end_time = std::chrono::system_clock::to_time_t(end);

    std::cout << "finished computation at " << std::ctime(&end_time)

              << "elapsed time: " << elapsed_seconds.count() << "s\n";

}