#include <iostream>

class Screen
{
public:
        void some_member () const;
        size_t get() const { return access_ctr; }
private:
        mutable size_t access_ctr = 0;
};

void Screen::some_member () const
{
        ++access_ctr;
}

int main()
{
        const Screen s;
        for (int i = 0; i < 5; ++i)
        {
                s.some_member();
                std::cout << s.get() << std::endl;
        }
}