Thread: trouble to measure time with time.h

hello ebverybody.
I need to measure the time in some statement and i have the following code to do that

Code:

#include <stdio.h>
#include <time.h>
int main () {
  clock_t time_before;
  clock_t time_after;
  int i_value=0;
double tot_time;
for(i=0; i<N_RUNS; i++)
    {
      i_value++;
    }
  time_after=clock();
  tot_time=((double)(time_after-time_before)/(double)CLOCKS_PER_SEC); /*time in seconds */
  printf("total time %f \n",tot_time);

The last statement print 0 when i test it. Can somebody tell me what is wrong whith those statement and how should i correct it

Watch the clock on the wall, then look at your processor spec and work out how many instructions it can execute in the time it takes the second hand to move.

Using clock() is like trying to time a bullet out of a gun using a sun dial.

You're going to need a much better timer to time short-lived code like that.
Do a board search for some of my RDTSC examples.

FAQ > How do I... (Level 2) > Time my application/function