Driver Resource Composition

#include <iostream>
using namespace std;

class Buffer {
private:
    int data;

public:
    Buffer() {
        cout << "Buffer created" << endl;
    }

    ~Buffer() {
        cout << "Buffer destroyed" << endl;
    }

    void write(int value) {
        data = value;
    }

    int read() const {
        return data;
    }
};

class RegisterBlock {
private:
    int reg;

public:
    RegisterBlock() {
        cout << "RegisterBlock created" << endl;
    }

    ~RegisterBlock() {
        cout << "RegisterBlock destroyed" << endl;
    }

    void write(int value) {
        reg = value;
    }

    int read() const {
        return reg;
    }
};

class Driver {
private:
    // Declare Buffer first
    Buffer buf;
    // Declare RegisterBlock second
    RegisterBlock regBlock;

public:
    // Constructor must store input values
    // Print "Driver initialized"
    Driver(int _bufVal, int regVal)
    {
        buf.write(_bufVal);
        regBlock.write(regVal);
        cout << "Driver initialized" << endl;
    }

    void print() const {
        // Print buffer value
        // Print register value
        cout << "Buffer value: " << buf.read() << endl
            << "Register value: " << regBlock.read() << endl;
    }

    ~Driver()
    {
        cout << "Driver destroyed" << endl;
    }
    // Destructor must print "Driver destroyed"
};

int main() {
    int a, b;
    cin >> a >> b;

    {
        Driver drv(a, b);
        drv.print();
    }

    return 0;
}