c++ - is this possible to inherit private class but make members public? -

i want have members inherited private. think saw example of making them public nevertheless fact derived private keyword. question: how it, , if possible shouldn't prohibited?

class u{ public:     int a; protected:     int b; private:     int c; };  class v : private u{ public:     int i;     //can make public again? }; 

how it?

perfectly possible, use using keyword.

shouldn't prohibited?

no need. can return members back accessibility not more initially. so, if base class has declared public , idea/restriction make private, doesn't hurt base class if drop restriction , leave public, in public @ beginning. cite "c++ programming language" best here.

a using-declaration cannot used gain access additional information. mecha- nism making accessible information more convenient use.

so if accessible in base class, , derived class protected or private keyword can remove restriction , return them initial level of access "transporting" them appropriate part (public,protected,private) in derived class definition.

class u{ public:     int a; protected:     int b; private:     int c; };  class v : private u{ public:     using u::b;     using u::a; };  int main(int argc, char** argv) {      v v;     printf("\nv: %d %d %d",v.a,v.a,v.b);      u u;     printf("\nu: %d %d %d",u.a,u.a,u.a);      return 0; }