Should I use `this` within a class?

Question

Within a member function of a class in C++, does it make a difference, if I use this->dataMember or just dataMember? What is considered better

Answer 1

I always use this when calling member functions.

1. It turns the function name into a dependent name so that base class member functions are found within a class template.
2. It suppresses argument-dependent lookup. ADL has its advantages, but it can lead to surprising behavior, and I like it if it's not getting in my way.
3. It has no real disadvantages, and so I use it for all member function calls for consistency reasons.
4. I program in Python a lot where an explicit self is mandatory, so it's not a real burden for me.

But for data members I use it only when necessary because there is no ADL taking place. To answer your specific questions:

Within a member function of a class in C++, does it make a difference, if I use this->dataMember or just dataMember?

Yes, if this is within a class template. Then dataMember is considered a non-dependent name, which can lead to semantic differences. For example:

#include 

int i = 1;

struct R {
  int i;
  R(): i(2) { }
};

template
struct S: T {
  void f() {
    std::cout << i << ' '     // selects ::i
              << this->i      // selects R::i
              << std::endl;
  }
};

int main() {
  S().f();
}

What is considered better style?

I don't think that there is a strong opinion within the community about this. Use either style, but be consistent.

Is there any performance difference?

I'm pretty sure there isn't.