Introduction

Iterators are an extremely important concept in C++. The STL aims to be as flexible and generic as possible, and iterators are a great help in that regard. Unfortunately, they are sometimes a bit tedious to use, which is why many novices avoid them and fall back to C-Style C++. A programmer who avoids iterators basically waives half the potential of the STL. This chapter deals with iterators and quickly casts some light on how they work. That very quick introduction is probably not enough, but the recipes are really here to give a good feeling for iterator internals.

Most container classes, but also old-school C-style arrays, in one or the other way, contain a range of data items. A lot of day-to-day tasks that process a lot of data items do not care how to get at that data. However, if we regard, for example, an array of integers and a linked list of integers and want to calculate the sum of all the items of both the structures, we would end up with two different algorithms...