boost chrono

#include <boost/chrono.hpp>
#include <cmath>

int main()
{
        boost::chrono::system_clock::time_point start = boost::chrono::system_clock::now();

        for ( long i = 0; i < 10000000; ++i )
        std::sqrt( 123.456L ); // burn some time

        boost::chrono::duration<double> sec = boost::chrono::system_clock::now() - start;
        std::cout << "took " << sec.count() << " seconds\n";
        return 0;
}