The answers for all exercises can be found in Section A.4.
The program from Exercise 2 in Chapter 4 needs to read the entire data file each time it runs. However, the Professor has a new router log file each day and doesn't want to keep all that data in one giant file that takes longer and longer to process.
Fix up that program to keep the running totals in a data file so the Professor can simply run it on each day's logs to get the new totals.
To make it really useful, what other features should be added to that program? You don't need to implement them!