代写关于Linked List的Lab小作业，包括一个需要用Recursion的Extra point代码。
Requirement
Implement the LListCursor class as defined on iLearn. Remember, a class invariant must be true at all times; it is an extra set of pre and post conditions. Methods without a precondition do not have a precondition beyond the class invariant.
The remove methods are fairly complex. I highly recommend you draw a diagram and think about each of the possible cases such as the list being empty, the cursor being at the item we are deleting, the cursor being at the start of the list, the cursor being at the end of the list, etc. If you stop by my office for help, I will ask to see your diagram for the method you are asking for help on. I have written one of the remove methods for you. I have also written a few test methods. You can use the checkList method as a helper for your tests as I did in one of the sample test methods I gave you.
In addition to your LListCursor.py file, also write your own unit test file named test_LListCursor.py. You may use mine as a starting point. My unit test file has 20 separate tests. You should test all the possible cases for the inserts and removes along with the other methods. See my one sample tests for how to check that a method properly raises an assertion. Note that you do NOT put parentheses after the method when you are using assertRaises to check if it raises an exception.
Extra
In Python, write two different implementations of a Bag class. A Bag is similar to a Set in that it is an unordered collection of items except that duplicates are allowed. Write one Bag in a file named BagList.py that stores the data as a list and write a separate implementation in a file named BagDictionary that uses a dictionary to store the data. Each implementation must pass the tests in the provided test Bag.py file. See the test file for the methods the Bag class must implement. Change the import statement at the top of the test Bag.py file depending on which implementation you are writing.
Write a C++ Bag class in files named Bag.h and Bag.cpp. Your code must pass all the tests in the provided main.cpp file.
Write two different recursive functions named base2AsString(n) and base2AsInt(n). The one returns a string such as “1011” when called with 11 and the other returns an int such as 1011 when called with 11. Your code must pass the tests in the provided test base2.py. Write the provided linked list assignment.