Granting Access: Inherit base as private : private inheritance « Class « C++ Tutorial

1. C++ Tutorial
2. Class
3. private inheritance

#include <iostream>
using namespace std;
   
class base {
  int i; // private to base
public:
  int j, k;
  void seti(int x) { i = x; }
  int geti() { return i; }
};
   
// Inherit base as private.
class derived: private base {
public:

  base::j; // make j public again - but not k
  base::seti; // make seti() public
  base::geti; // make geti() public
   
  int a; // public
};
   
int main()
{
  derived ob;
   
  ob.j = 20; // legal because j is made public in derived
   
  ob.a = 40; // legal because a is public in derived
  ob.seti(10);
   
  cout << ob.geti() << " " << ob.j << " " << ob.a;
   
  return 0;
}