c++， 派生类的构造函数和析构函数

#include <iostream>
using namespace std;
#include <string>

class Basic
{
public:
    string m_name;
    Basic();
    Basic(string name);
    Basic(Basic& bc);

    ~Basic();

    Basic& operator=(const Basic& bc) 
    {
        cout << "Basic::operator=()\n";
        this->m_name = bc.m_name;
        return *this;
    }
};
Basic::Basic()
{
    cout <<"Basic::Basic()"<<endl;
}
Basic::Basic(string name)
{
    m_name = name ;
    cout <<"Basic::Basic(string)"<<"name:"<<m_name<<endl;
}
Basic::Basic(Basic &bc)
{
    this->m_name = bc.m_name;
    cout <<"Basic::Basic(Basic&)"<<"name:"<<bc.m_name<<endl;
}

Basic::~Basic()
{
    cout<<"this is "<<m_name << "Basic::~Basic()"<<endl;;
}


class Derived:public Basic
{
public:
    int m_dx;
    Derived();
    Derived(string name);//m_name
    ~Derived();

    void show();
};
Derived::Derived()
{
    cout <<"Derived::Derived()"<<endl;
}
Derived::Derived(string name)
    :Basic(name)
{
    cout <<"Derived::Derived(string)"<<"name:"<<m_name<<endl;
}
Derived::~Derived()
{
    cout <<"this is "<<m_name <<"Derived::~Derived()"<<endl;;
}
void Derived::show()
{
    cout<<"name: "<<m_name<<endl;
}
void test()
{
    Derived dc1("dc1");
    cout<<""<<endl;

    Derived dc2("dc2");//m_bx
    cout<<""<<endl;


    dc1 = dc2 ;
    cout<<"next is dc1.show():  ";
    dc1.show();
    cout<<""<<endl;
}
int main() {
    test();
    while(1);
}
/**
Basic::Basic(string)name:dc1
Derived::Derived(string)name:dc1

Basic::Basic(string)name:dc2      //生成派生类对象时，先调用基类的构造函数
Derived::Derived(string)name:dc2  //在调用自身的构造函数

Basic::operator=()  //调用了基类的operator= ，并正确地对Derived::m_name进行了赋值。 
　　　　　　　　　　　 //测试时，假如把基类的operator=实现为空函数，那么Derived对象也不能对Derived::m_name进行重新赋值。除非再手动实现Derived的operator=。
　　　　　　　　　　　 //operator= 只有一个，Drived中如果手动实现了，将会覆盖基类的=。就是说，不会执行基类的operator=。

next is dc1.show(): name: dc2 this is dc2Derived::~Derived() //析构和构造的调用顺序刚好相反。先调用自身的析构函数，再调用基类的析构函数。 
this is dc2Basic::~Basic() 
this is dc2Derived::~Derived()//在一个函数体中，先实现的对象后释放。 
this is dc2Basic::~Basic() 
**/

class Basic
{
public:
    int m_number;
    string m_name ;
    char m_sex;//‘m‘ ‘w‘
    Basic(int n ,string name , char s);
};
Basic::Basic(int n,string name ,char s)
    :m_number(n)
    ,m_name(name)
    ,m_sex(s)
{
//     this->m_name = name;
//     this->m_number = n;
//     this->m_sex = s;
}

class Derived:public Basic
{
public:
    int m_age;
    string m_addr;
    Derived(int n,string name,char s,int a, string addr);
};
Derived::Derived(int n,string name,char s,int a, string addr)
    :Basic(n,name,s)
    ,m_age(a)
    ,m_addr(addr)
{

}