Protected Access

#include <iostream>
using namespace std;

class BaseDevice {
protected:
    int id;
};

class DerivedDevice : public BaseDevice {
public:
    void setId(int v) { id = v; }
    void printId() { cout << "Device ID: " << id; }
};

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