What is Virtual Destructor?
Using virtual destructors, you can destroy objects without knowing their type - the correct
destructor for the object is invoked using the virtual function mechanism. Note that
destructors can also be declared as pure virtual functions for abstract classes.
if someone will derive from your class, and if someone will say “new Derived”, where
“Derived” is derived from your class, and if someone will say delete p, where the actual
object’s type is “Derived” but the pointer p’s type is your class.