Using override and final for virtual methods

Unlike other similar programming languages, C++ does not have a specific syntax for declaring interfaces (which are basically classes with pure virtual methods only) and also has some deficiencies related to how virtual methods are declared. In C++, the virtual methods are introduced with the virtual keyword. However, the keyword virtual is optional for declaring overrides in derived classes, which can lead to confusion when dealing with large classes or hierarchies. You may need to navigate throughout the hierarchy up to the base to figure out whether a function is virtual or not. On the other hand, sometimes, it is useful to make sure that a virtual function or even a derived class can no longer be overridden or derived further. In this recipe, we will see how to use the C++11 special identifiers override and final to declare virtual functions or classes.

Getting ready

You should be familiar with inheritance and polymorphism in...