cpp_playground/class/inherit.cpp

#include <iostream>

class Base1 {
    virtual void func() {}
    char ch;
    // int val;
};

class Base2 {
    virtual void func() {}
    // char ch;
    int val;
};

class Base3 {
    // virtual void func() {}
    char ch;
    // int val;
    // double val;
};

class Base4 {
    // virtual void func() {}
    // char ch;
    int val;
    // double val;
};
class Derived : public Base1, public Base2, public Base3, public Base4 {
    virtual void func() {}
    double val;
};

int main() {
    Derived d1;
    Derived* pd1 = &d1;
    Base1* pb1 = &d1;
    Base2* pb2 = &d1;
    Base3* pb3 = &d1;
    Base4* pb4 = &d1;

    std::cout << "notice how those casts are performed according to member alignments" << std::endl;
    std::cout << pd1 << std::endl
              << pb1 << std::endl
              << pb2 << std::endl
              << pb3 << std::endl
              << pb4 << std::endl;

    std::cout << sizeof(Derived) << std::endl
              << sizeof(Base1) << std::endl
              << sizeof(Base2) << std::endl
              << sizeof(Base3) << std::endl
              << sizeof(Base4) << std::endl;
}