std::chrono::time_point<Clock,Duration>::time_point

#include <chrono>
#include <iostream>
 
using Clock = std::chrono::high_resolution_clock;
using TimePoint = std::chrono::time_point<Clock>;
 
void print_ms(const TimePoint& point) 
{
    using Ms = std::chrono::milliseconds;
    const Clock::duration since_epoch = point.time_since_epoch();
    std::cout << std::chrono::duration_cast<Ms>(since_epoch).count() << " ms\n";
}
 
int main() 
{
    const TimePoint default_value = TimePoint(); // (1)
    print_ms(default_value); // 0 ms
 
    const Clock::duration duration_4_seconds = std::chrono::seconds(4);
    const TimePoint time_point_4_seconds(duration_4_seconds); // (2)
      // 4 seconds from start of epoch
    print_ms(time_point_4_seconds); // 4000 ms
 
    const TimePoint time_point_now = Clock::now(); // (3)
    print_ms(time_point_now); // 43098276 ms
}