Explain the need for "Virtual Destructor"?

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Explain the need for "Virtual Destructor"?..

Answer / lylez00

If A is a base class, and from that, B is derived, and a
dynamically allocated object of type B is deleted via a
pointer of type A, then B's destructor will not be invoked
unless A's destructor is virtual.

A *a = new B();
delete a; // won't invoke B's destructor unless A's
destructor is virtual

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Explain the need for "Virtual Destructor"?..

Answer / p govind rao

A destructor can be declare virtual. virtual destructor is
mainly useful during inheritance.

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

class derv
{ char *p;
public :
derv(){ptr=nes char[2];}
~derv(){delete ptr;}

} ;

main()
{
base *baseptr=new derv();
delete baseptr;
}

If base class, and derived class, and a dynamically
allocated object of type derived is deleted via a pointer
of type base, then derived's destructor will not be invoked
unless base's destructor is virtual.

base *baseptr = new derv();
delete baseptr; // won't invoke B's destructor unless A's
destructor is virtual