Question

How to init constant integer array class member? I think that in same case classic array isn’t best choice, what should I use instead of it?

class GameInstance{
    enum Signs{
        NUM_SIGNS = 3;
    };
    const int gameRulesTable[NUM_SIGNS][NUM_SIGNS]; //  how to init it?
public:
    explicit GameInstance():gameRulesTable(){};
};

Answer 1

Make it static?

class GameInstance{
    enum Signs{
        NUM_SIGNS = 3};
    static const int gameRulesTable[2][2];
public:
    explicit GameInstance(){};
};

...in your cpp file you would add:
const int GameInstance::gameRulesTable[2][2] = {{1,2},{3,4}};