Simple and fun C ++ keywords mutable

Mutable is a fun C ++ keyword and it was my first time. So I checked msdn and found that it was a fun keyword.
First, it can only modify non-const, non-static class data members.
Second, it is used to break through the const function.
Again, it is such a function.

Class X {public: // logically, getflag only obtains my m_flag status, so it is modified to const //. However, I need to know some of the dynamic statuses, so Mutable was born. Bool getflag () const {m_accesscount ++; return m_flag;} PRIVATE: bool m_flag; // The rules of this keyword are non-const and non-staticmutable int m_accesscount ;};

Conclusion: The idea is simple, the design is simple, and the function is simple.