We saw several advanced types:

1) enumerated types

2) unions

3) void *
	
4) function pointers

All of these mechanisms allow for some sort of generic
data structures.  For example, enumerated types and unions were used together
to create tagged unions, allowing a single struct to hold two different, but
related, kinds of data.  void* and function pointers are used to store and 
operate on data of unknown type.

You should be comfortable using data structures that have been declared using
either of these mechanisms.