If you want to try the clock() difference on a real-world example, I provide you with my code for measuring different sort methods:

Code:

#define ARRAY_SIZE 10000
void swap(int *a, int *b)
{
int tmp;
tmp = *a;
*a = *b;
*b = tmp;
}
void bubbleSort(int *array, int size)
{
int swapped = 0;
int x,tmp;
do
{
swapped = 0;
for (x = 0; x < size-1;x++)
{
if (array[x]>array[x+1])
{
swap(&array[x], &array[x+1]);
swapped = 1;
}
}
} while (swapped);
}
int main(int argc, char *argv[])
{
int array[ARRAY_SIZE];
int i;
clock_t start, end;
/* initialize array with ARRAY_SIZE random numbers */
srand(time(NULL));
for (i = 0; i < ARRAY_SIZE; i++)
{
array[i] = rand(); // random number between 0 and RAND_MAX
}
/* start the timer */
start = clock();
bubbleSort(array, ARRAY_SIZE);
end = clock();
/* Print out the difference */
printf ( "The interval was: %f seconds\n", (double)( end - start ) / (double)CLOCKS_PER_SEC );
getchar();
return 0;
}