Equivalent to copying cells or automatically filling a selection by dragging the fill selection handle with the mouse
[C++]
static int FillAuto(
   const CXlOper& destination_ref,
   unsigned short copy_only = 0
);
Destination_ref is the range of cells into which you want to fill data.
Copy_only is a number specifying whether to copy cells or perform an AutoFill operation.
Zero if the function has been called successfully; non-zero
            if the function could not be called.
            See Error codes for a list
            of return values.
See the Microsoft Excel on-line Help for full details about
            this function.
Header: xlfuncs.h