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


int main()
{
clock_t begin, end;

    while(1)
    {
        begin = clock();
        sleep(1); // delay for 1 sec
        end = clock();
        printf("Execution time = %fn",((float)(end-begin)/CLOCKS_PER_SEC));

    }

}

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

int main() {

    time_t begin;
    time(&begin);

  // Somethings

   time_t end;
   time(&end);

  printf("Execution time %fn", difftime(end, begin));
  return (0);
}

#include <stdio.h>
#include <time.h>
#include <sys/time.h>

int main() {

  struct timeval  tv;
  gettimeofday(&tv, NULL);

double begin =
  (tv.tv_sec) * 1000 + (tv.tv_usec) / 1000 ;


 sleep(2);

 gettimeofday(&tv, NULL);

double end =
  (tv.tv_sec) * 1000 + (tv.tv_usec) / 1000 ;

  printf("Execution time %fn", end - begin);
  return (0);
}

#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>
#define ELPS_TIME(func_name) do {
    struct timeval tval_before, tval_after, tval_result;
    gettimeofday(&tval_before, NULL);
    func_name;
    gettimeofday(&tval_after, NULL);
    timersub(&tval_after, &tval_before, &tval_result);
    printf("Time elapsed: %ld.%06ld secondsn",
        (long int)tval_result.tv_sec,
        (long int)tval_result.tv_usec); } while(0)

static void test_func1() {
    printf("%s:", __FUNCTION__);
    sleep(1);
}

static void test_func2() {
    printf("%s:", __FUNCTION__);
    sleep(2);
}

int main() {
    ELPS_TIME(test_func1()); //calling test_func1
    ELPS_TIME(test_func2()); //calling test_func2
    return 0;
}

test_func1:Time elapsed: 1.000103 seconds
test_func2:Time elapsed: 2.000974 seconds