cp_cv_ws/cpp_pkgs/src/inheritance.cpp

#include <iostream>

/**
 * c->A->D
 *  ->B->
 */
using namespace std;
//基类
class D
{
public:
    D(){cout<<"D()"<<endl;}
    ~D(){cout<<"~D()"<<endl;}
    void print(){cout<<"print d"<<endl;}
    virtual void print_virtual() = 0;//{cout<<"print virtual d"<<endl;}
protected:
    int d;
};

class B:public D
{
public:
    B(){cout<<"B()"<<endl;}
    ~B(){cout<<"~B()"<<endl;}
    void print(){cout<<"print b"<<endl;}
    virtual void print_virtual(){cout<<"print virtual b"<<endl;}
protected:
    int b;
};

class A:public D
{
public:
    A(){cout<<"A()"<<endl;}
    ~A(){cout<<"~A()"<<endl;}
    void print(){cout<<"print a"<<endl;}
    virtual void print_virtual(){cout<<"print virtual a"<<endl;}
protected:
    int a;
};

class C:public B, public A
{
public:
    C(){cout<<"C()"<<endl;}
    ~C(){cout<<"~C()"<<endl;}
    void print(){cout<<"print c"<<endl;}
    virtual void print_virtual(){cout<<"print virtual c"<<endl;}
protected:
    int c;
};

void global_print(D& s){
    s.print();
    s.print_virtual();
}

int main()
{
    cout << "Hello World!" << endl;
    //D d; //抽象类，含纯虚函数
    B b;
    A a;
    C c;   //D, B, A ,C
    //cout<<sizeof(d)<<endl;
    cout<<sizeof(b)<<endl;
    cout<<sizeof(a)<<endl;
    cout<<sizeof(c)<<endl;
    //global_print(d);
    global_print(b);
    global_print(a);
    // global_print(c); // 多继承，重构二义性
    return 0;
}