I would suggest:
Code:
struct pos {
    int x;
    int y;
    int z;

    pos() {} // perhaps you should zero initialise the member variables?

    pos(int a, int b, int c) : x(a), y(b), z(c) {}

    bool operator==(const pos& p) const
    {
        return (x == p.x) && (y == p.y) && (z == p.z);
    }
};
You might also consider if the member variables should actually be private.