code blocks and g++ error "is private"

I'm getting these errors with the code blocks IDE(with g++ compiler) "is private" for every member variable. As far as I know it is only legal to use the private variables within the other members, which is what i'm doing. This is the code of my cpp

/*
bullsAndCows.cpp

*/

using namespace std;

//enum class state {_bull, _cow, _none};

class bullsAndCows {
private:
    const int m_size{4};
    bool m_guessed{false};
    std::vector<char> m_digit;
    std::vector<state> m_digitState;

public:
    bullsAndCows() {
        m_guessed = false;
        for(int i = 0; i < m_size; i++)
            m_digitState[i] = state._none;
    }

    void bullsAndCows::setGuessed(bool value) { _guessed = value; }
    bool bullsAndCows::getGuessed() { return _guessed; }
    void bullsAndCows::setDigit(char value, int i) { m_digit[i] = value; }
    char bullsAndCows::getDigit(int i) { return m_digit[i]; }
    void bullsAndCows::setDigitState(state value, int i) { m_digitState[i] = value; }
    state bullsAndCows::getDigitState(int i) { return m_digitState[i]; }

};

this the code of my main, where i'm testing. #include "bullsAndCows.h"

using namespace std;

int main()
{
    bullsAndCows game;
    for(int i = 0; i < game.m_size; i++) {
        cin >> game.m_digit[i];
        cout << game.m_digit[i];
    }

    return 0;
}

The c++11 flag is activated on the compiler