Re: copy construct

From:

Saeed Amrollahi <amrollahi.saeed@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 8 Aug 2009 00:59:58 -0700 (PDT)

Message-ID:

<aac7d652-77dd-4f67-860f-fd9e09858155@p9g2000vbl.googlegroups.com>

On Aug 8, 8:52 am, exergy <nicholas.entr...@gmail.com> wrote:

Hello, if I have a class like this:

class Node{
   private:
      int x;
      Node* parent;
   public:
       Node(const Node& N)
         {
               ......
         }
        Node& operator =(const Node& n)
       {
                ......
        }

      ~Node()
       {
             .....
       }
        // other member functions
}

[SA] };

How do I make a copy of private field Node* parent itself? I read some
references online, some use "new" operator to allocate dynamic memory,
so what I did was

   Node(const Node& p)
     {
       x=p.x;
       Node temp=*(p.parent)
       parent=new node(temp);
     }
However, x value was copied, not the parent pointer.
anyone can help?

[SA] What is wrong with reference semantic (copy semantic)? consider
the following code:

class Node {
// as before
public:
Node() : x(0), parent(0) {} // for root
Node(int xx, Node* p) : x(xx), parent(p) {}
Node(const Node& N) : x(N.x), parent(N.parent) // pointer semantic
{
}
// as before
};

void use_node()
{
Node root; // root of say tree
Node n(1, &root); // one node
Node n2(2, &n); // another node
Node n3 = n2; // copy of node
}

of course we can use copy semantic ...

I hope it helps
-- Saeed Amrollahi