virtual destructor

[sanjay123456]

Dear friends

In following peace of code which type of destructor are deleate and why ?

 
class Base {
        // ...
        virtual ~Base();
    };
 
    class Derived : public Base {
        // ...
        ~Derived();
    };
 
    void f()
    {
        Base* p = new Derived;
        delete p;    // virtual destructor used to ensure that ~Derived is called
    }
 

sanjay

[vermarajeev]

Dear friends

In following peace of code which type of destructor are deleate and why ?

 
class Base {
        // ...
        virtual ~Base();
    };
 
    class Derived : public Base {
        // ...
        ~Derived();
    };
 
    void f()
    {
        Base* p = new Derived;
        delete p;    // virtual destructor used to ensure that ~Derived is called
    }
 

sanjay

Object are always deleted in the reverse order of construction, In the example above, the type of object is of type Derived and the pointer to object is of type Base hence when you say delete, first the Derived class destructor is called then the Base class's.
Also remember that, virtual destructor are use when you are trying to delete Derived class object via a Base class pointer.