多继承

#include <iostream>
using namespace std;

class OBJ1
{
public:
        OBJ1()
        {
                cout<<"construct OBJ1"<<endl;
        }
};

class OBJ2
{
public:
        OBJ2()
        {
                cout<<"construct OBJ2"<<endl;
        }
};

class Base1
{
public:
        Base1()
        {
                cout<<"construct Base1"<<endl;
        }
};

class Base2
{
public:
        Base2()
        {
                cout<<"construct Base2"<<endl;
        }
};


class Base3
{
public:
        Base3()
        {
                cout<<"construct Base3"<<endl;
        }
};

class Base4
{
public:
        Base4()
        {
                cout<<"construct Base4"<<endl;
        }
};

/*
多继承的构造顺序:
1,按照父类被继承的顺序先构造虚拟基类，再构造非虚拟基类
2,成员对象按照声明时的顺序被定义,对于组合的其他类的对象调用构造函数
3，类自己的构造函数
*/
class Derived : public Base1, virtual public Base2,
                                public Base3, virtual public Base4
{
public:
        Derived() : Base4(),Base3(),Base2(),Base1(),obj2(),obj1()
        {
                cout<<"Derived ok."<<endl;
        }
protected:
        OBJ1 obj1;
        OBJ2 obj2;
};


void main()
{
        Derived d;
        cout<<"this is ok."<<endl;
}