main.cpp

#include <map>
#include <iostream>

using namespace std;


class NetworkInterface {

public:
    int a = 5;

    NetworkInterface(int a): a(a) {}
};


class SubnetInterface : public NetworkInterface {
public:

    SubnetInterface(int a): NetworkInterface(a * 10) {}
};


class SwitchInterface : public NetworkInterface {
public:

    SwitchInterface(int a): NetworkInterface(a * 100) {}

};


int main() {
    std::map<std::string, NetworkInterface> interfaces = {
        {"subnet", SubnetInterface(1)},
        {"switch", SwitchInterface(1)},
    };

    NetworkInterface ni = NetworkInterface(10);
    cout << "ablabla: " << ni.a << endl;

    SubnetInterface si = SubnetInterface(10);
    cout << "blablab: " << si.a << endl;

    SwitchInterface swi = SwitchInterface(10);
    cout << "aaaaaaa: " << swi.a << endl;

    cout << interfaces["subnet"].a;
}