Question

I have a class which I intend to use for performing calculations. I declare one static object of the class elsewhere which I use to obtain results. The class has one public function apart from the constructor.

public:
    double getProbability(PlayerStats &p1, PlayerStats &p2, Score &score);

As you can see, I have three objects as input parameters. My class then has two private functions which are called from getProbability(). One requires p1 and p2, the other requires all three of the parameters

My question is this. Is it better to pass these objects as parameters to the function or is it better to create private member variables and use these.

So for example

   double MyClass::getProbability(PlayerStats &p1, PlayerStats &p2, Score &score){
            otherFunction(p1,p2);
            anotherFunction(p1,p2,score);
             ....
    }

or

     double MyClass::getProbability(PlayerStats &p1, PlayerStats &p2, Score &score){
            this->p1 = p1;
            this->p2 = p2;
            this->score = score;
            otherFunction();   //use member variables in these functions
            anotherFunction();
             ....
    }       

Answer 1

It’s better to pass them as parameters, as they don’t really represent class state and storing them as members will probably be more performance costly than simply continuing to pass around the references.

But it doesn’t really look like your class has any state at all, which leads me to believe all of these methods should be free-functions in a suitable namespace rather than members of a class (perhaps you come from a Java background?).