Virtual Destructors in C++

Example:

struct A
{
int x;
~A(cout<<"A destroyed"<<endl;); //nonvirtual
};
struct B: A //inheriting from a class that has a non-virtual dtor. very bad idea!
{
int y;
~B(cout<<"B destroyed"<<endl;);
};
Now try to run the following code:

int main()
{
A* p = new B;
delete p;
}

Next, change the dtor of A to virtual and run the same code once more. Can you see the difference?