Programming

Hey all,

i need a program to get the CPU ticks at certain points of my program. So, i thought about using the clock function, but i'm having a hard time figuring out how it really works. I wrote this simple program to try to understand it but it made me feel more confused:

#include <stdio.h>
#include <string.h>
#include <time.h>

clock_t start, end;
double cpu_time_used;

int main(int argc, char* argv[])
{
clock_t start, end;
double cpu_time_used;
long int i;

for (i=1; i<ITERATIONS; i++)
;
start = clock();

for (i=1; i<1000000000; i++)
;
end = clock();

printf("start: %d\n",start);
printf("end: %d\n",end);

cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
printf("cpu_time_used: %f\n",cpu_time_used);

return 0;
}

when i run my program with ITERATIONS = 100000, i get as result
start: 0
end: 2760000
cpu_time_used: 2.760000

it also happens when ITERATIONS = 1.

Why is that?!?

thanks in advance,
Breno Kastrup