BasicsOfComputerSoftwareEngineering/OOP/test.cpp

#include <iostream>

class A {
protected:
    int a;

public:
    A(int _a) : a(_a) {
    }
    void display() {
        std::cout << a << std::endl;
    }
};

class B : virtual public A {
protected:
    int b;

public:
    B(int _a, int _b) : A(_a+1), b(_b) {
    }
    void display() {
        A::display();
        std::cout << b << std::endl;
    }
};

class C : virtual public A {
protected:
    int c;

public:
    C(int _a, int _c) : A(_a + 2), c(_c) {
    }
    void display() {
        A::display();
        std::cout << c << std::endl;
    }
};

class D : public B, public C {
protected:
    int d;

public:
    D(int _a, int _b, int _c, int _d) :A(_a), B(_a, _b), C(_a, _c), d(_d){};

    void display() {
        A::display();
        B::display();
        C::display();
        std::cout << d << std::endl;
    }
};

int main() {
    D objD(1, 2, 3, 4);
    objD.display();
    return 0;
}