Refactor Driver–Bus Relationship

#include <iostream>
using namespace std;

class Bus {
public:
    Bus() {
        cout << "Bus ready" << endl;
    }

    ~Bus() {
        cout << "Bus stopped" << endl;
    }

    void write(int addr, int val) {
        cout << "Bus write: " << addr << " " << val << endl;
    }
};

Bus bus_global;

// WRONG: Each Driver becomes its own Bus
class Driver{
public:
    Bus& bus;
    Driver() : bus(bus_global) {
        cout << "Driver started" << endl;
    }

    void operate(int addr, int val) {
        bus.write(addr, val);
    }

    ~Driver() {
        cout << "Driver stopped" << endl;
    }
};

int main() {
    int a1, v1, a2, v2;
    cin >> a1 >> v1 >> a2 >> v2;

    {
        Driver d1;
        Driver d2;
        d1.operate(a1, v1);
        d2.operate(a2, v2);
    }

    return 0;
}