newbie,determine the size of an array

lets say you have a dynamically allocated array called darray
how do u determine the size of the array?

i tried:
int size = sizeof(darray) * sizeof(arraytype)
but the sizeof(darray) dosen't check the whole array. it only checks the sizeof of the pointer to the first element.

i also tried
int size = sizeof(*darray) * sizeof(arraytype)
but i guess that was a stupid move cuz it would give me the data at the location of the pointer which is not an array just one element.

i think i also tried something else but i can't remember what lol.

can someone tell me the formula for finding the size of the array, both dynamic and static?
well i think the first thing i tried would work for static arrays so.

Generally you use a variable to keep track of how much memory you ask for.

Just to expand on Dave's suggestion:

If you created the array yourself, you already know how large the array is, because you malloc'ed or new'ed the memory. If you need that information elsewhere in your program store it as a variable or a #define (depending on your design).

If you called some API call that returned a pointer to a dynamically created array, I sincerely hope it also gives you the size of the array. If it does not, either a) shoot the person who wrote the API, or b) get yourself a new API.

On second thought, you should probably do both.

lol, thanks for ur advice that would get me in jail, then i'll never be able to program again