Re: [Dev-C++] Assingment operator

[Per W. <pw...@ia...>]

The only thing you might check for is of "origTree.root == root". In that
case either both trees are empty, or you have done "mytree = mytree;"
Without the test, your code would always destroy the tree for the
"mytree = mytree;" case.

/Per W

On Mon, 9 Jun 2003, Socha, David F wrote:

> With an assignment operator for a user defined class, a binary Search
> Tree class for example, would it be a problem if my overloaded
> assignment operator only handled cases where you were assigning one tree
> to another.
>
> Here is some sample code:
>
> /****************************************************************************
> Overloaded assignment operator
> Used for: assigning the value of one tree to another tree
> Sent: A reference to the original tree
> Returns: A reference to a tree
> Works by: First checking to see if the tree bieng copyied to has data in it.
> If it does, the deleteTree function is called to empty the tree/free up all the
> memory in the tree.
>      Second, checks to see if the tree being copyied has any data in it.  If it
> does, the copyTree function is called to copy the data from the original tree to
> the copy tree.  If the original tree does not have data on it (root == NULL)
> then the root of the copy tree will be set to null.
> ****************************************************************************/
>
> template<typename T> BST& BST<T>::operator= (const BST& origTree){
>      if(root){
>           destroyTree(root);
>      }
>
>      if(orig.root){
>           copyTree(origTree.root, root);
>      }
>      else{
>           root=NULL;
>      }
>
>      return *this;
> }
> //End operator=
>
> /****************************************************************************
> copyTree function
> Used by the copy constructor / asignment operator to copy the tree
> Sent: pointer to the original node, pointer to the node being copied to
> Returns: Nothing
> Works by: Creating a new node on the tree being copied, copy the data to the
> node, checks to see if a left node exists on the tree, if yes
> repeat the process using on the left node, if not, do nothing.  Then checks
> the right, if it exists repeat process on the right side, if not, do nothing
> NOTE: This function is a recursive process
> ****************************************************************************/
> template<typename T> void BST<T>::copyTree(Node* origNode, Node* copyNode){
>      copyNode = new Node(origNode->data);
>
>      if(origNode->left){
>           copyTree(origNode->left, copyNode->left);
>      }
>
>      if(origNode->right){
>           copyTree(origNode->right, copyNode->right);
>      }
> }
> //End copyTree
>
> I am using the version 4.9.8.0 of Dev C++
>
> Should this work or will I have a problem with this.
> Thanks,
> David Socha
>
>
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