Originariamente inviato da ZioBeLu
e appunto come faccio a misurarlo se gia mi esce 1000000 subito
non hai bisogno di orologi 
codice:
#include <stdio.h>
#include <time.h>
#define GREAT_VAR 3000000000
#define INTER_VAR 1000000000
int main(void)
{
int start, elaps, rel = 0;
double end = 0.0;
unsigned int var = 1;
start = time(NULL);
while (var <= GREAT_VAR) {
if (var % INTER_VAR == 0) {
elaps = time(NULL) - start;
rel = elaps - rel;
printf("ELAPSED TIME FOR %u CALLS: %d sec.\n%s%d sec.\n",
var, elaps, " RELATIVE: ", rel );
}
++var;
}
end = (double) elaps / (double) GREAT_VAR;
printf("TIME FOR EACH CALL: %.10f sec.\n", end);
return 0;
}