实现复制构造函数 [英] implementing a copy constructor

问题描述

我有以下类定义，它需要一个复制构造函数，因此可以进行深层复制来复制原始指针。有人可以建议如何做到最好吗？

I have the following class definition and it needs a copy constructor so deep copies are made to copy the raw pointers. Can anybody advice on how to best do this?

使用 xerces-c ++ for XML

Using xerces-c++ for XML

class XMLDocument 
 {
 private:
  typedef std::vector<XML::XMLNode> v_nodes;
 public:
  XMLDocument::XMLDocument();
  XMLDocument::XMLDocument(const XMLDocument& copy); 
  XMLDocument::~XMLDocument();

  XMLDocument& operator=(XMLDocument const& rhs);

  void CreateDocument(const std::string& docname);
  void AddChildNode(XMLNode& node);
  void RemoveNode(XMLNode& node);
  void AddNodeValue(XMLNode& node, const std::string& value);
  void AddNodeValue(XMLNode& node, int value);
  void AddNodeValue(XMLNode& node, double value);
  void AddNodeValue(XMLNode& node, float value);
  std::string GetXMLAttributes();
  std::string GetXMLAttribute(const std::string& attrib);
  std::string GetXMLNodeText(XML::XMLNode& node);
  std::string DumpToString();
  XMLNode GetXPathNode(const std::string xpathXpression);
  XMLNode GetNode(const XMLNode &currentnode);

  typedef v_nodes::iterator nodes_iterator;
  nodes_iterator begin()
  {
   nodes_iterator iter;
   iter = xmlnodes.begin();

   return iter;
  }
  nodes_iterator end()
  {
   nodes_iterator iter;
   iter = xmlnodes.end();

   return iter; 
  }


 private:
  v_nodes xmlnodes;

  bool InitializeXML();
  DOMImplementation* impl; //Abstract
  DOMDocument* document; //Abstract
  DOMElement* rootelement; //Abstract

 };

创建DOMDocument 调用函数，而因此 DOMElement。因此，我不能只是在这些指针上调用new。

The DOMDocument is created calling a function and so is the DOMElement. So I can't just call new on these pointers.

不确定我是否只是从字面上重新创建了所有这些对象？

Not sure if I just literally recreate all these object?

示例：

document = impl->createDocument(0, "mydoc", 0);

谁经历了一次投票失败却没有给出原因？???

Who's gone on a downvote rage and not given a reason???

推荐答案

此页面可能会有所帮助：

http://icu-project.org/docs/papers/cpp_report/the_anatomy_of_the_assignment_operator.html

This page might certainly help:
http://icu-project.org/docs/papers/cpp_report/the_anatomy_of_the_assignment_operator.html

请注意，它们是编写复制构造函数和赋值运算符之间的区别，但是这一点也在本文中进行了讨论。

Note their is a difference between writing a copy-constructor and an assignment operator but this point is also discussed in the paper.

这篇关于实现复制构造函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！