¿Cómo mostrar por pantalla el tiempo transcurrido en unity?

#include <iostream>
#include <time.h>

using namespace std;

int main ()
{
  time_t timer;
  struct tm y2k = {0};
  double seconds;

  y2k.tm_hour = 0;   y2k.tm_min = 0; y2k.tm_sec = 0;
  y2k.tm_year = 100; y2k.tm_mon = 0; y2k.tm_mday = 1;

  time(&timer);  /* get current time; same as: timer = time(NULL)  */

  seconds = difftime(timer,mktime(&y2k));

  cout << seconds << " seconds since January 1, 2000 in the current timezone" << endl;
  return 0;
}