C++考前复习——继承构造的顺序

        根据书上所说，虚继承后由第二级派生类对底层的基类进行构造，而第一级派生类不对底层基类进行构造，所以需要加上base(i);

        派生类构造时先对基类进行构造，所以是按照(base),(base1,base2),(mem1,mem2)的顺序构造的；

        因为继承时public base2, public base1           base2在base1前面，所以先构造base2;

        因为定义时base2 mem2;

                          base1 mem1;先定义的base2所以先构造base2；


#include<iostream>
using namespace std;
class base
{
public:
base(int i){ cout << i; }
~base(){}
};
class base1 :virtual public base
{
public:
base1(int i, int j = 0) :base(j){ cout << i; }
~base1(){}
};
class base2 :virtual public base
{
public:
base2(int i, int j = 0) :base(j){ cout << i; }
~base2(){}
};
class derived :public base2, public base1
{
public:
derived(int a, int b, int c, int d) :mem1(a), mem2(b), base1(c), base2(d), base(a)
{
cout << b;
}
private:
base2 mem2;
base1 mem1;
};
int main()
{
derived ob(1, 2, 3, 4);
}