C语言库clock()函数

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

int main () {
   clock_t start_t, end_t, total_t;
   int i;

   start_t = clock();
   printf(Starting of the program, start_t = %ld\n, start_t);

   printf(Going to scan a big loop, start_t = %ld\n, start_t);
   for(i=0; i< 10000000; i++) {
   }

   end_t = clock();
   printf(End of the big loop, end_t = %ld\n, end_t);

   total_t = (double)(end_t - start_t) / CLOCKS_PER_SEC;
   printf(Total time taken by CPU: %f\n, total_t  );
   printf(Exiting of the program...\n);

   return(0);
}