Returns the processor clock time used since the beginning of an
implementation-defined era (normally the beginning of the
program). The returned value divided by CLOCKS_PER_SEC
results in the number of seconds. If the value is unavailable,
then -1 is returned.
clock_t ticks1, ticks2;
printf("Took %ld ticks to wait one second.\n",ticks2-ticks1);
printf("This value should be the same as CLOCKS_PER_SEC which is %ld.\n",CLOCKS_PER_SEC);