Measuring time in C

Question

I\'m trying to measure some activity in C (Matrix multiplying) and noticed that I should do something like this:

clock_t start = clock();
sleep(3);
clock_t e         


        

Answer 1

As a side note, if you want to measure execution time in a more precise manner (milliseconds), time is not precise enough. You can use gettimeofday instead:

#include 
#include 
#include 

int main() {
    long start, end;
    struct timeval timecheck;

    gettimeofday(&timecheck, NULL);
    start = (long)timecheck.tv_sec * 1000 + (long)timecheck.tv_usec / 1000;

    usleep(200000);  // 200ms

    gettimeofday(&timecheck, NULL);
    end = (long)timecheck.tv_sec * 1000 + (long)timecheck.tv_usec / 1000;

    printf("%ld milliseconds elapsed\n", (end - start));

    return 0;
}