C++17 STL Cookbook

How it works...

In order to be able to transform a normal iterator into a reverse iterator, it must at least have support for bidirectional iteration. This requirement is fulfilled by any iterator of the bidirectional category or higher.

A reverse iterator kind of contains a normal iterator and mimics its interface completely, but it rewires the increment operation to a decrement operation.

The next detail is about the begin and end iterator positions. Let's have a look at the following diagram, which shows a standard numeric sequence kept in an iterable range. If the sequence goes from 1 to 5, then the begin iterator has to point to the element 1, and the end iterator must point one element past 5:

When defining reverse iterators, the ...