Linked List Database

The database files that you used for one of the introduction to programming
labs are coming back again. They all follow this format:

10081957 101440980 Betty Lamprey NY
24061927 103980155 Pinky Fellowes OR
14031947 106100903 Oliver Kringle ND
05011948 108690448 Larry Brown KS
28101964 111180924 Adolf Davies UT
27021971 112200747 Bella Napster OK
16071973 112550407 Marianne Stone OR
04051957 113070570 Apu Mitchell TX
23101940 113220519 Jilly Aston WY
07061967 114680858 Matilda Vincent MI

One person per line, and for each person we are given five things - date of
birth, social security number, first name, last name, and state of residence.

The birth date format is slightly different this semester. Instead of the
usual YYYYMMDD, it has been switched around to DDMMYYYY, so Betty Lamprey's
10081957 means the 10th of August 1957.

This URL gives you access to 9 different data files. Same format, different
lengths:
          http://rabbit.eng.miami.edu/class/een118/labs/152/
if you are working on rabbit, you don't need to download the files into
your own directory, you can access them directly like this:
          f.open("/home/www/class/een118/labs/152/dbfile1.txt");

You are to define four data structures:

1. A simple object to represent a person.

2. A linked list of persons.

3. An object to represent a state, storing the state's name or abbreviation
   and the linked list of all people who live in it.

4. A linked list of states.

Your program needs a method for adding a new person object into the main linked
list, this will require the creation of a new state object when you are adding
the first person from any given state. Do not pre-fill the list of states with
50 empty entries, only create a state object when/if a person residing in that
state appears.

Your program should be interactive, accepting and obeying the following simple
commands from the user.

1. read filename     e.g. "read /home/www/class/een118/labs/152/dbfile1.txt"

  Read the contents of the named file, adding each person to the data structures.
  Note that the files all list people in order of ascending social security
  number. That ordering must be kept in the linked lists.

2. states

  Print a list of all the states that appear in the databsae. 

3. list state        e.g. "list FL"

  Print the details of everyone from the given state

4. oldest state
   youngest state    e.g. "oldest NY"

  Find and print the oldest/youngest person in the given state

5. find fname lname     e.g. "find Larry Brown"

  Find and print the named person, not knowing which state they are in

6. move ssn oldstate newstate    e.g. "move 108690448 KS MD"

  The person with the given social security number has moved to a diferent
  state. Update the data structures to reflect this change

7. merge state1 state2 newstate    e.g. "merge NC SC CR"

  Why do we need a North Carolina and a South Carolina? Perhaps they should
  be merged to form a single state of Carolina. That's what this operation does:
  A new state CR is created, and all the people from the two old states NC and SC
  are moved into it, after which NC and SC are removed.
  Remember that it is necessary to keep all the people in every state in order
  of increasing social security number.