When should I make explicit use of the `this` pointer?

Question

When should I explicitly write this->member in a method of a class?

Answer 1

I found another interesting case of explicit usage of the "this" pointer in the Effective C++ book.

For example, say you have a const function like

  unsigned String::length() const

You don't want to calculate String's length for each call, hence you want to cache it doing something like

  unsigned String::length() const
  {
    if(!lengthInitialized)
    {
      length = strlen(data);
      lengthInitialized = 1;
    }
  }

But this won't compile - you are changing the object in a const function.

The trick to solve this requires casting this to a non-const this:

  String* const nonConstThis = (String* const) this;

Then, you'll be able to do in above

  nonConstThis->lengthInitialized = 1;