c++ - Getting a time difference in milliseconds -

i´m trying thought simple have looked everywhere , can´t figure out. i´m new c++ , have no understanding of templates , such.

i need function measures time program´s launch point in milliseconds, like:

class timecounter {      private:         long starttime;         long currenttime;         long timedifference;     public:         long gettime(); }  timecounter::timecounter () {     starttime = time.now(); }  long timecounter::gettimepassed () {     currenttime = time.now();     timedifference = timenow - timestart;     return timedifference; } 

i´ve tried clock() / clocks_per_seconds result slower second.

can me out?

thank much!

i writing similar system delta time game engine.

using std::chrono library, here's example:

#include <iostream> #include <chrono> #include <thread>  class timer {     // alias our types simplicity     using clock             = std::chrono::system_clock;     using time_point_type   = std::chrono::time_point < clock, std::chrono::milliseconds > ; public:     // default constructor stores start time     timer()     {         start = std::chrono::time_point_cast<std::chrono::milliseconds>(clock::now());     }      // gets time elapsed construction.     long /*milliseconds*/ gettimepassed()     {         // new time         auto end = clock::now();          // return difference of times         return (end - start).count();     }  private:     time_point_type start; };  int main() {     timer t;      std::this_thread::sleep_for(std::chrono::seconds(5));      std::cout << t.gettimepassed();      std::cin.get(); }