can you be more specific?
on #1, if you are talking about referencing a variable, that means you are not showing it's value , but instead you show it's location in the memory, thus allowing you to mess with the original value.
for more information look up pointers, * , & and memory allocation
as for the second one, the only time I can think of a structure having a "hole" is if it were part of a linked list, or some other usage of a pointer, and the the link or "reference" to that data was lost, thust creating something of a memory "leak" or "hole" meaning unrecoverable data until you reboot, it'll fill up your memory(RAMS)
Karl
kb244@kb244.com
Experienced in : C++(both VC++ and Borland),VB1(dos) thru VB6, Delphi 3 pro, HTML, Visual InterDev 6(ASP(WebProgramming/Vbscript)