Question

我一直在寻找派生类的复制构造函数的例子，但我真的不明白我应该怎么写这个。

我有三个课程LinkList，CD和Media。

我为Media和LinkList但不是CD编写了副本构造函数，它是Media的派生类，其成员变量的LinkList 。

请不要对此提供任何帮助。

class LinkList
{
  private:      
    struct ListNode
    {
      T value1;                
      struct ListNode *next;  
    }; 

    ListNode *head;   // List head pointer

  public:
    //***Constructor***
    LinkList();
    LinkList(const LinkList<T> &);
    //***Destructor***
    ~LinkList();

    //***LinkList Operations***
    //....operation functions
};      

//***Constructor***
template <class T>
LinkList<T>::LinkList()
{
    head = NULL;
}

//***Copy Constructor***
template <class T> 
LinkList<T>::LinkList( const LinkList &listObj )
{

    head = NULL;
    ListNode *nodePtr;
nodePtr = listObj.head;
    while(nodePtr != NULL)
    {
      appendNode(nodePtr->value1);
      nodePtr = nodePtr->next;
}
}

class Media
{
  private:

    string title;
    string length;

  public:       
    //***Constructors***
     Media();
     Media(string, string);
     Media(const Media &obj);
     //***destructor***
     ~Media();

     //***Mutators***
    void setTitle(string);
    void setLength(string);

    //***Accessors***
    string getTitle();
    string getLength();

    //Overloaded Operators

    bool operator < (const Media &);
    bool operator > (const Media &);
    bool operator != (const Media &);
    bool operator == (const Media &right);
 };

/*****Implimentation*********/
//***Constructors***
Media::Media()
{
title = "  ";
length = " ";
}

//***Constructors***
Media::Media(string t, string l)
{
title = t;
length = l;
}

//***Copy Constructor***
Media::Media(const Media &obj)
{
title = obj.title;
length = obj.length;
}

//LinkList structure for CD class

struct CdContence
{
string song;
string length;
};



class CD : public Media
{
public:

      LinkList<CdContence> Cd;

      //***Constructors***
      CD(string, string);
  CD();

      //***destructor***
      ~CD();

      //***Mutators***
      void setCD(string, string, string, string);

     //***Accessors***
     LinkList<CdContence> getCD();


     //Overloaded Operators

     bool operator < (CD &);
     bool operator > (CD &);
     bool operator != (CD &);
     bool operator == (CD &);
};

/*****Implimentation*********/
//***Constructors***
CD::CD(string T, string L)
{
 setTitle(T);
 setLength(L);
 LinkList<CdContence>Cd;

   cout<<"CD CONSTRUCTOR2"<<endl;
}

CD::CD() : Media()
{
LinkList<CdContence>Cd;

cout<<"CD CONSTRUCTOR"<<endl;
}

CD::CD(const CD &obj) :Media(obj)
{
//not sure what to put here since the member variable is 
// a linklist

}

Answer 1

使用@Remy Lebeau提供的解决方案

CD::CD(const CD &obj) :Media(obj), Cd(obj.Cd) {}

使用linklist成员复制派生类的构造函数

1 个答案: