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

The main (or I can say, the only) purpose of this pointer is that it points to the object used to invoke a member function.

Base on this purpose, we can have some cases that only using this pointer can solve the problem.

For example, we have to return the invoking object in a member function with argument is an same class object:

class human {

... 

human & human::compare(human & h){
    if (condition)
        return h;       // argument object
    else 
        return *this;   // invoking object
    }
};