Re: Interaction of delete and destructor

I use the code below to study delete and destructor.

#include <iostream>
using namespace std;

struct A {
  virtual ~A() { cout << "~A()" << endl; }; //LINE1

  void operator delete(void* p) {
    cout << "A::operator delete" << endl;
    free(p);
  }
};

struct B : A {
  void operator delete(void* p) {
    cout << "B::operator delete" << endl; //LINE2
    free(p);
  }
  ~B(){ cout << "~B()" << endl; }; //LINE3
};

int main() {
  A* ap ;
  B *bp = new B;
  ap = bp;
  delete ap; //LINE4
}

The output of the code is:
~B()
~A()
B::operator delete

I can not understand the output. When LINE4 is executed, LINE1 is
executed, right?
Since ~A() is virtual, LINE3 is called. How can LINE2 be executed?
"delete ap" calls A's destructor. Then B's destructor is called. Can
B's destructor call B's operator delete?

In general, delete invokes destructor, right? Can destructor invoke
delete?

Thanks a lot. I can not find the answer from my C++ books.

Jack