সি clock

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

int main() {
  clock_t start = clock();

  for (long i = 0; i < 1000000; i++) {
  }

  clock_t end = clock();

  printf("%f",
    (double)(end - start) / CLOCKS_PER_SEC
  );

  return 0;
}