Simple execution timer (C++)

chrono_timer.cpp

#include <chrono>

/*
 * ...
 */

auto start = std::chrono::high_resolution_clock::now();
/* 
 * do stuff
 */
auto stop = std::chrono::high_resolution_clock::now(); 
auto duration = std::chrono::duration_cast<std::chrono::nanoseconds>(stop - start); //or milliseconds
unsigned long duration_count = duration.count();