Run Time Type Information (RTTI) in C++

Why RTTI?
Up-casting (treating sub-class as base class ) works fine, for example,

However, down-casting might not be safe as correctness cannot be determined by the C++ compiler. See the following example.

So we need RTTI to support both up-casting and down-casting.

Mechanisms for RTTI
1. dynamic_cast operator
2. typeid operator and type_info class

See details of dynamic_cast operator here.

RTTI typeid operator
• Obtains type info of an object/expression which is a reference to a standard library type called type_info.
• usage: typeid( object) - The usage is similar to “sizeof”.
• To get the name of the type, use typeid(object).name().