Soooo Close- Interesting Question

[darms21]

I am having trouble tweaking my non-recursive preorder to print in a non-recursive preorder fashion. Any ideas?


Preorder recursive

   template< typename T >
   void BinaryTree<T>::preorder( BinaryTreeNode<T> * p )
   {
	   if (  p == NULL )  return  ;
	   else
	   {
		   cout <<  p->data   << "  ";
		   preorder( p->left );			   
		   preorder( p->right );
   }
   }

[darms21]

Any ideas? This is what I have so far but am getting an error

   template< typename T >
   void BinaryTree<T>::nr_preorder( BinaryTreeNode<T> * p )
   {
	   if (  p == NULL )  return ;
	   else
	   {
		   queue< BinaryTreeNode<T> >   que;
		   que.push( *root );
			   while ( !que.empty() )
		   {
			   BinaryTreeNode<T>  temp  =  que.front();
			   que.pop();
			   cout  <<  temp.data  << "  ";
			   if ( temp.left   !=  NULL )  que.push( * temp.left );	
			  
                            if ( temp.right  !=  NULL )  que.push( * temp.right);	
	   }
		   }
	   }

Error:

Error 1 error C2597: illegal reference to non-static member 'hgjhgj::BinaryTree<T>::root'

[darms21]

-

[darms21]

Trying a stack instead of a queue...

	   
template< typename T >
   void BinaryTree<T>::nr_preorder( )
 	   {
	   if (  root == NULL )  return ;
	   else
	   {
		   stack< BinaryTreeNode<T> >   que;
		   que.push( *root );
			   while ( !que.empty() )
		   {
			   BinaryTreeNode<T>  temp;
			   que.push(root);
			   cout  <<  temp.data  << "  ";
			   if ( temp.left   !=  NULL )  que.push( * temp.left );	
			   if ( temp.right  !=  NULL )  que.push( * temp.right ;	  
			   }
		   }
	   }

getting error:

Error 1 error C2664: 'void std::stack<_Ty>::push(fghfh::BinaryTreeNode<T> &&)' : cannot convert parameter 1 from 'fghfh::BinaryTreeNode<T> *' to 'fghfh::BinaryTreeNode<T>

[darms21]

Again I am trying to print the nodes of a binary tree - preorder - using a stack.

[darms21]

Is the forum stumped!?

[shacktar]

To do preorder using a stack, you should push the right child then the left child.

Your last compiler error is happening because on line 13, you're doing:

que.push(root);

where root is a BinaryTreeNode<T>* (pointer) whereas que is a stack of BinaryTreeNode<T> (not pointers). I would make it a stack of pointers to BinaryTreeNodes to avoid copying on push.

[darms21]

Fixed that part but Im still not at a viable solution...

[darms21]

Hmmmm