Easily measure elapsed time

Question

I am trying to use time() to measure various points of my program.

What I don\'t understand is why the values in the before and after are the same? I understand thi

Answer 1

The values printed by your second program are seconds, and microseconds.

0 26339 = 0.026'339 s =   26339 µs
4 45025 = 4.045'025 s = 4045025 µs

Answer 2

I usually use the following:

#include <chrono>
#include <type_traits>

using perf_clock = std::conditional<
    std::chrono::high_resolution_clock::is_steady,
    std::chrono::high_resolution_clock,
    std::chrono::steady_clock
>::type;

using floating_seconds = std::chrono::duration<double>;

template<class F, class... Args>
floating_seconds run_test(Func&& func, Args&&... args)
{
   const auto t0 = perf_clock::now();
   std::forward<Func>(func)(std::forward<Args>(args)...);
   return floating_seconds(perf_clock::now() - t0);
} 

It's the same as @nikos-athanasiou proposed except that I avoid using of a non-steady clock and use floating number of seconds as a duration.