Quick clock

ttt.cpp

// clang++ -O3 time.cpp -o ttt

#include <chrono>
#include <iostream>


int main() {
    auto last = std::chrono::duration_cast<std::chrono::nanoseconds>(
            std::chrono::system_clock::now().time_since_epoch()).count();
    while(true) {
        auto const now = std::chrono::system_clock::now();
        auto const ns = std::chrono::duration_cast<std::chrono::nanoseconds>(
            now.time_since_epoch()).count();
        std::cout << (ns / std::nano::den) << '.' << (ns % std::nano::den)
            << " -- " << (ns - last) << "    \r" << std::flush;
        last = ns;
    }
}