C++ POlymorphic INhertiance example with SMArt pointers
The example attempts to provide a modern C++ implementation of the following concepts:
- Polymorphism
- Smart pointers
- Containers
It provies in a way to safely and efficiently manage large sets of derived classes.
The classes are organized as follows:
Shape is the abstract base class used to derive the more specific classes from.
Because we want to use std::shared_ptr to address the class, it derives from std::enable_shared_from_this. This allows for Shape and any derived class to safely emit shared_ptr's.
Through polymorphism the is_XXX() functions provide a way to test whether Shape_p was created from a derived class (through conversion to bool), and even to obtain a shared_ptr to the derived class (as shown in main() in main.cpp)
The shared_ptr is obtained through shared_from_this() member of enabled_shared_from_this derived by Shape. To convert it to the another T of shared_ptr<T> in the same control block, std::dynamic_pointer_cast is used.
Given the above we can use Shape_p in a container to hold classes of all derived types. The usage of standard library containers and smart pointers give an excellent flexibility in passing the objects around, while ensuring ellegant and correct memory management.
Is welcome!