How can I make an instant-dependant static variabe in a class method?

Question

I have a function in a class the more or less works like so:

class Player {
private:
    Object* minions[16]
public:
    void Summon(Object* obj);
};

Player::Summon(Object* obj) {
    static int i = 0;
    if (i == 16)
        return;
    minions[i] = obj;
    i++;
}

The problem arise when trying to use more than one player, like so:

Player playerone;
Player playerthree;
playerone.Summon(new Object("o1"));
playerthree.Summon(new Object("o2"));

o1 is located in playerone.minions[0], as is expected, however, o2 is located in playerthree.minions[1], the Summon() function using the same i variable. Is there a way to make the Summon() function use a static i variable for a single instance, but use separate i variables for each instance? I know I could do something like make a for loop to the first spot in minions[] equal to NULL, or make i a member of Player directly, but I want to know if there is a better way before I do either of those.

Answer 1

Change Object* minions[16]; to a std::vector<Object*> minions;. That way you can just use minions.size() to know how many there are, or minions.push_back(obj); to add one without worrying about array index stuff.

Answer 2

Why don't you simply put i in each Player? I'd rename it something like summonned_minion_count, but that's the actual intent of what you want to do.

Answer 3

Making a local variable static is effectively making it global. You should simply make i a data member of class Player. And probably give it a more descriptive name.

Answer 4

You need to make your i a member variable of Player.

Or even better you could do something like this:

#include <vector>

class Player {
private:
    static int const MAX_MINION_COUNT = 16;
    std::vector<Object *> minions;
public:
    void Summon(Object* obj) {
        if (minions.size() < MAX_MINION_COUNT) {
            minions.push_back(obj);
        }
    }
};