Container classes are general purpose template classes that store items of a given type in memory. Standard C++ already includes many containers as part of the Standard Template Library (STL).
Qt provides its own container classes, so when we write Qt programs, we can use both the Qt and the STL containers. If you are already familiar with the STL containers and have STL available on your target platforms, there's no particular reason to use the Qt containers.
In this chapter, we review the most important STL and Qt containers. We also look at QString and QVariant, two classes that have many things in common with containers and that can be used as alternatives to containers in some contexts.
For more information about the STL classes and functions, a good place to start is SGI's STL web site: http://www.sgi.com/tech/stl/.