Program to find time used by Loop

#include <time.h>

#include <stdio.h>

  main()

  {

    time_t start, end;

    volatile long unsigned t;

    start = time(NULL);

    for(t=0; t<500; t++) ;

    end = time(NULL);

    printf("Loop used %f seconds.\n", difftime(end, start));

    getch();

    //return 0;

  }