Protected Access

#include <iostream>
using namespace std;

class BaseDevice {
protected:

      int id;

};

class DerivedDevice : public BaseDevice {
public:

      void setId(int v) { this->id = v; }
      void printId() { cout << "Device ID: " << this->id; }

};

int main() {
   DerivedDevice d;
   d.setId(101);
   d.printId();
   return 0;
}