SPECADT05: Sample Solution Exercise 3

Dear course participants,

please find attached a sample solution to Exercise 3. Most of your solutions
were more or less okay but there were also many minor or major problems.
So before you go to the implementation in Exercise 5, please cross-check
your solution with the solution presented below (which may also have its problems, of course).

There is one major problem which no one noticed: when deleting or renaming
an entry which is a *directory* rather than a file, also all other entries with
that directory as an ancestor directory in its path have to be renamed. In
the attached solution, I exclude this case by a corresponding check (for sake of simplicity), you may also do so in your implementation.

Best regards, WS