C库函数 difftime()

#include <stdio.h>

#include <time.h>



int main () {

   time_t start_t, end_t;

   double diff_t;



   printf("Starting of the program...\n");

   time(&start_t);



   printf("Sleeping for 5 seconds...\n");

   sleep(5);



   time(&end_t);

   diff_t = difftime(end_t, start_t);



   printf("Execution time = %f\n", diff_t);

   printf("Exiting of the program...\n");



   return(0);

}