The point of the example is that this is how NOT to do it in C++.

There are two better options:

  void f(int n, int x) {
      Gadget p(n); // Stack allocated
      // ...
      if (x < 100) throw new Exception("Weird!); // no leak
      if (x < 200) return;
      // ...
  }

Or, if it really has to be a pointer:

  void f(int n, int x) {
      std::unique_ptr<Gadget> p = new Gadget(n); // Smart pointer
      // ...
      if (x < 100) throw new Exception("Weird!); // no leak
      if (x < 200) return;
      // ...
  }

Both will be automatically freed as soon as the scope is exited.