Exceptional C++: 47 Engineering Puzzles, Programming Problems, and Solutions

Chapter 23. Class Relationships—Part 2

Difficulty: 6

Design patterns are an important tool in writing reusable code. Do you recognize the patterns used in this Item? If so, can you improve them?

A database manipulation program often needs to do some work on every record (or selected records) in a given table, by first performing a read-only pass through the table to cache information about which records need to be processed, and then performing a second pass to actually make the changes.

Instead of rewriting much of the common logic each time, a programmer has tried to provide a generic reusable framework in the following abstract class. The intent is that the abstract class should encapsulate the repetitive work by first, compiling a list of table ...