Delta_G:
http://arduino.cc/en/Reference/SizeofDoesn't work? Is that because it is being passed as an argument to the function?
No. As I said earlier, when you pass the array to a function, it is converted to a pointer to the first element. This means in the caller when the compiler knows it is an array, sizeof returns what you expect (size of each element times the number of elements). Inside the function, sizeof returns the size of a pointer (2 bytes in the case of the Arduino, 4 bytes on 32-bit systems, 8 bytes for 64-bit systems).