dynamic_cast
http://en.cppreference.com/w/cpp/language/dynamic_cast
typeid
http://en.cppreference.com/w/cpp/language/typeid
http://en.cppreference.com/w/cpp/header/typeinfo
http://en.cppreference.com/w/cpp/types/type_index
原文：http://my.oschina.net/robslove/blog/478230