Storing dynamic number of objects

Question

Say I have a player class and I wanted to store an amount of players given by input. Here's what I've done; I'm just wondering if there's anything wrong with it:

class Obj {
public:
int id;
Obj (int id): id (id) {};
};
vector <Obj> objects;

int main () {
int nObj = 0;
cin >> nObj;
for (int i = 0; i < nObj; ++i) {
objects.push_back (Obj (i));
}
return 0;
}

It just seems too easy to be okay.

Answer 1

Actually, it is that easy :)

The things I would change if I were you are:
Don't put vector<Obj> objects; in global scope,

id shouldn't be publicly accessable, put it under private: instead,

Use a prefix for class data members
id = _id or m_id or mID, whatever you like. It's just easier to recognize member variables,

lastly id is probably never going to change so you might as well make it const.

Answer 2

I would suggest using vector.reserve(nObj); before pushing back with the loop, as this reserves the memory ahead of time instead of it reallocating everytime it doesnt have enough room, which will slow things down.

Answer 3

It is that easy because they are complex stuff in the vector class ^^

Answer 4

@Dennis I know, I was using my phone to type that out, so I had everything public. In my actual code, the vector isn't global, for I know of the dangers by making variables global ;) Thanks for the answers!

Answer 5

Ah yea, I forgot about that one, Aklex, good observation. :)

Answer 6

@aklex ah okay, thanks. Good tip

Answer 7

Oh yea, the phone explains everything. I avoid typing code on a phone just for that reason. ^^