Count time of action (using chrono)

time_count.cpp

#include <chrono>
#include <iostream>
 
int main(int ac, char** av) {
    auto start = std::chrono::system_clock::now();
    // action
    auto end = std::chrono::system_clock::now();
    std::chrono::duration<double> total = end - start;
    std::cout << "time : " << total.count();
    return 0;
}