Regarding Virtual Destructor

Question

I have two classes Parent and child. Child is derived from Parent class. Parent class is having Show method as virtual. But it do not contain any virtual destructor.
Parent *p;
Child c;
p = &c;
p->show();
delete p;
When i run the above code it calls both classes destructor. But as i read somewhere in case of upcasting if base class destructor is not virtual then compiler will not call derived class destructor.

And 2nd Scenario with Same above classes, when i write below piece of code inside main,

Parent *p = new Derived;
p->show();
delete p;

Then its just called base class destructor and not derived.

Can someone tell me the difference? Why in first scenario it has called base plus derived both?

Answer 1

In first case how can u apply delete operator to pointer p which points to statically allowed object c.... That's not correct... And the deatructor is getting called for c because it's a object whose scope will end when main() ends

Answer 2

In second case it's the actual deletion taking place through delete operator which is applied to base pointer... Hence no derived class destructor call...

Answer 3

In simple terms u should delete only stuff u allocate through new or get unexpected results

Answer 4

Thanks Saurabh B