RTTI

static_cast: This is used for the normal/ordinary type conversion. This is also the cast responsible for implicit type coersion and can also be called explicitly. You should use it in cases like converting float to int, char to int, etc.

dynamic_cast: This cast is used for handling polymorphism. You only need to use it when you're casting to a derived class. This is exclusively to be used in inheritence when you cast from base class to derived class.

const_cast: can be used to remove or add const to a variable. This can be useful if it is necessary to add/remove constness from a variable.

reinterpret_cast: This is the trickiest to use. It is used for reinterpreting bit patterns and is extremely low level. It's used primarily for things like turning a raw data bit stream into actual data or storing data in the low bits of an aligned pointer.

The typeid keyword is used to determine the class of an object at run time. It returns a reference to std::type_info object, which exists until the end of the program.^[3] The use of typeid, in a non-polymorphic context.

#include     // cout
#include     // for 'typeid'

 class Person
  {
    public:
       virtual ~Person() {}
  };

 class Employee : public Person
 {
 };

 int main() 
 {
   Person person;
   Employee employee;
   Person* ptr = &employee;
   Person& ref = employee;
   // The string returned by typeid::name is implementation-defined
   std::cout << typeid(person).name() << std::endl;   // Person (statically known at compile-time)
   std::cout << typeid(employee).name() << std::endl; // Employee (statically known at compile-time)
   std::cout << typeid(ptr).name() << std::endl;      // Person* (statically known at compile-time)
   std::cout << typeid(*ptr).name() << std::endl;     // Employee (looked up dynamically at run-time
                                                      //           because it is the dereference of a
                                                      //           pointer to a polymorphic class)
   std::cout << typeid(ref).name() << std::endl;      // Employee (references can also be polymorphic)

   Person* p = nullptr;
   try
      {
       typeid(*p); // not undefined behavior; throws std::bad_typeid
      }
       catch (...)
      {
      }

   Person& pRef = *p; // Undefined behavior: dereferencing null
   typeid(pRef);      // does not meet requirements to throw std::bad_typeid
                      // because the expression for typeid is not the result
                      // of applying the unary * operator
  }

Output (exact output varies by system):

Person
Employee
Person*
Employee
Employee