You can return a struct (by value, i.e. not via a pointer to the struct) which has a float as its only member as well if you really want to return the array. This may copy but the compiler should be able to optimise the copy out.
Don't return the address of a global variable, it doesn't scale well (meaning: doesn't scale at all) if you need to call it recursively or on multiple threads.
EDIT: I see Alvaro suggested making a Point class, missed that, it's the same as what I suggested using a class instead of a struct.