How can we call "delete this; " in a const-member function?

Question

I saw the code snippet as follows:

class UPNumber {
public:
  UPNumber();
  UPNumber(int initValue);
  ...

  // pseudo-destructor (a const member function, because
  // even const objects may be destroyed)
  void destroy() const { delete this; } // why this line is correct???

  ...

private:
  ~UPNumber();
};

First, I am sure that above class definition is correct. Here is my question, why we can define the function 'destroy' as above? The reason being asking is that why we can modify 'this' in a const-member function?

Answer 1

That works for the same reason that this work:

const int* upn = new int();
delete upn;

You can delete a pointer to a const-qualified object. The const-qualification on the member function just means that this has a type const UPNumber*.