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 style? Is there any performance difference?
(I am not talking about the case where a local variable has the same name as the data member, in which case you must, to my knowledge, use this-> to distinguish between them.)
Answer
As a general rule, it's a question of local conventions. Most of the
places I've seen do not use this-> except when necessary, and that's
the convention I prefer as well, but I've heard of people who prefer to
use it systematically.
There are two cases when it is necessary. The first is if you've hidden
the name with the same name in local scope; if e.g. you have a member
named toto, and you also named your function argument toto. Many
coding conventions mark either the member or argments to avoid this
case, e.g. all member names start with my or m_, or a parameter name
will start with the.
The other case is that this-> can be used in a template to make a name
dependent. This is relevant if a template class inherits from a
dependent type, and you want to access a member of the base, e.g.:
template <typename T>
class Toto : public T
{
public:
int f()
{
return this->g();
}
};
Without the this-> here, g() would be a non-dependent name, and the
compiler would look it up in the context of the template definition,
without taking the base class into consideration.