Value-based collection classes are simpler to understand and manipulate. You create a linked list of integers or doubles, for example, or a hash table of shorts. Stored types can be more complicated, like the RWCStrings, but the important point is that they act just like values, even though they may contain pointers to other objects. When an object is inserted into a value-based collection class, a copy is made. The procedure is similar to C’s pass-by-value semantics in function calls.

In a reference-based collection class, you store and retrieve pointers to other objects. For example, you could create a linked list of pointers to integers or doubles, or a hash table of pointers to RWCStrings.