How to get the execution time of a code fragment in nanoseconds using chrono?

Question

I have a function and I wish to get the time taken by the compiler to execute it (the runtime). But as the process can be fast, I wish to get the time in nanoseconds, to see all changes.

I tried using chrono, like this:

using namespace chrono;

auto start = high_resolution_clock::now();
/* code block */
auto end = high_resolution_clock::now();

cout<<duration_cast<nanoseconds>(end - start) . count();

However, I just get a 0. Please help me correct my code!

Answer 1

have you looked here:http://en.cppreference.com/w/cpp/chrono/duration

Answer 2

@Ace
Sir, why is it that with a steady clock like in your program, I could get a non-zero value but with a high resolution clock, I couldn't?