Data Structures
•Linear Linked list...
• private:
• node * head;
• node * tail;  //???helpful?
•Absolute lists:  (a poor choice)
–holes: how to deal with them? add a position number to the contents of each node....don’t really allocate nodes for each hole!!!!
–insert, retrieve, removal requires traversal
–how can a tail pointer help? if data is entered in order by position!
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