#how do we know object type in runtime :? that could be if: the language support RTTI
##type introspection
figuring the metadata at runtime
https://en.wikipedia.org/wiki/Type_introspection
##C++ specific
###dynamic_cast way:
Dynamic cast an object to a class, do we get a bad_cast exception, then it's not the right type
be cautious base class must have at least one virtual method!!
http://stackoverflow.com/a/351865/2730737
###type_id way:
#include <typeinfo>
string s = typeid(YourClass).name()http://stackoverflow.com/a/4325139/2730737
##type reflection
manipulating the metadata at runtime
https://en.wikipedia.org/wiki/Type_reflection
the word binding!
types, functions and values determination at run/compile time (dynamic loading, dispatching and binding)
http://programmers.stackexchange.com/questions/200115/what-is-early-and-late-binding/200123#200123
the four types of polymors
Subtype polymorphism (runtime polymorphism).
Parametric polymorphism (compile-time polymorphism).
Ad-hoc polymorphism (overloading).
Coercion (implicit or explicit casting).
http://www.catonmat.net/blog/cpp-polymorphism/
scope resolution operator ::
use to force traversing from the global namespace downword while figuring out which class to use
http://stackoverflow.com/a/4269064/2730737