[c++]容器類。繼承類的構造和析構

#include<iostream>
using namespace std;
class Base
{
    int x;
public:
    Base(int a)
    {
        x = a;
        cout<<"father constructing "<<x<<endl;
    }
    ~Base()
    {
        cout<<"father destructing "<<x<<endl;
    }
};
class Dervied:public Base
{
    int y;
    Base B2,B1;//只與定義順序有關
public:
    Dervied(int a = 0,int b = 0,int c = 0,int d = 0):B1(d),Base(b),B2(c),y(a)//與參數列表的順序無關
    {
        cout<<"son constructing "<<y<<endl;
    }
    ~Dervied()
    {
        cout<<"son destructing "<<y<<endl;
    }
};
int main()
{
    Dervied(1,2,3,4);
    return 0;
}