Welcome back! In part 3 I discussed classes, polymorphism, references and templates, and finally built a source indexer out of basic containers that achieves 60MB/s indexing speed. In this part we continue with further C++ features that you can use to spice up your code ’line by line’, without immediately having to use all 1400 pages of ‘The C++ Programming Language’. There is frequent reference to the indexing example from part 3 so you may want to make sure you know what that is about.