Thread: measure time complexity

Hello

I'd like to measure time complexity that its needed for some algorithm/function to complete in my c++ application. I'd like to have it in miliseconds, double format (example: 0.253ms)

I've tried doing the following:

Code:

#include <boost/date_time/posix_time/posix_time_types.hpp>

//..

boost::posix_time::ptime start = boost::posix_time::microsec_clock::universal_time();
function();

boost::posix_time::time_duration time = boost::posix_time::microsec_clock::universal_time() - start;
std::cout << "done in: " << (double)(time.total_microseconds()/1000.0) << " ms\n";

But this will only output 0.

What am I doing wrong?

Is there any better way of doing this?

Thanks for help!