Note, by the way, that you can not use the "sizeof" operator on arrays that have been passed to a function, since arrays are always passed by reference (a pointer), and the size of a pointer is always 2.
int myarray[15];
void loop() {
operate(myarray);
}
void operate(int arr[])
{
Serial.print(sizeof(arr));
}
Will print "2."
Yes, there are reasons to support things like dynamically sized arrays, and arrays that contain information about their actual size. But the C language doesn't support either one; it's a "primitive" language.