dynamic_cast operator

dynamic_cast operator

Polymorphic cast of class type objects

  postfix-expr  := dynamic_cast <  type-id  > (  expression  )

The dynamic_cast operator performs a polymorphic cast on a pointer or reference to an object of class type. If expression is a pointer or reference to a base class, type-id can be a pointer or reference to a derived class. If the dynamic type of the object is not that of type-id or a class derived from type-id , the cast fails. If expression is a pointer, failure returns a null pointer; if expression is a reference, failure throws std::bad_cast . Casts from a derived to an unambiguous, accessible base class always succeed.

If expression is a null pointer, the result is a null pointer. If type-id is a pointer to void , the cast succeeds and returns a pointer to the most-derived object that expression represents.

Example

 struct base {}; struct derived : base {}; base* b = new derived; derived* d =  dynamic_cast  <derived*>(b);

Example

See Also