c++11 std::chrono

#include <iostream> 
#include <iomanip>
#include <ctime>
#include <chrono>

int main (int argc, char ** argv)
{
    auto begin_clock = std::chrono::system_clock::now();

    std::chrono::system_clock::time_point now = std::chrono::system_clock::now();
    std::time_t time = std::chrono::system_clock::to_time_t(now +
            std::chrono::hours(24*5));
    struct tm ti = *std::localtime(&time);

    char date_time_buf[32];
    sprintf(date_time_buf, "%04d-%02d-%02d %02d:%02d:%02d", 1900 + ti.tm_year,
            ti.tm_mon + 1, ti.tm_mday, ti.tm_hour, ti.tm_min, ti.tm_sec);

    std::cout << date_time_buf << std::endl;


    auto end_clock = std::chrono::system_clock::now();
    std::cout << std::chrono::duration_cast<std::chrono::microseconds>
    (end_clock - begin_clock).count() << std::endl;

    return 0;   
}