private List <ISBNclass> GetAllIsbns(BSTnode current, List <ISBNclass> currentList)
{
if (current == null)
{
return(currentList);
}
ISBNclass alISBN = new ISBNclass();
alISBN.ISBN = current.bstKey;
currentList.Add(alISBN);
GetAllIsbns(current.LeftNode, currentList);
GetAllIsbns(current.RightNode, currentList);
return(currentList);
}
public List <ISBNclass> GetISBN()
{
ISBNclass currentISBN = new ISBNclass();
List <ISBNclass> isbnList = new List <ISBNclass>();
BSTnode currentBSTnode; // walk the tree by using this pointer to the current node
Stack myStack = new Stack(); // instantiate the .NET supplied stack class, which will hold objects
if (bstTop == null) // if the stack is empty ...
{
return(null); // nothing to print
}
else// adjust our pointer to the top node in the BST
{
currentBSTnode = bstTop;
}
bool done = false; // get out of our while loop when this is set to true
while (!done) // loop until we are done
{
if (currentBSTnode != null)
{
isbnList.Add(new ISBNclass(currentBSTnode.bstKey));
}
if (currentBSTnode == null) // if there is no node here
{
if (myStack.Count == 0) // and the stack is empty, we have walked the entire tree, so done
{
done = true;
}
else// otherwise go back up the tree one level, by doing a pop
{
currentBSTnode = (BSTnode)myStack.Pop(); // (need to cast object back to a BSTnode)
currentBSTnode = currentBSTnode.RightNode; // now go down the right side
}
}
else // if we have not moved down to a null
{
myStack.Push(currentBSTnode); // save this upper node onto the top of the stack
currentBSTnode = currentBSTnode.LeftNode; // and take a step down the left side
}
}
return(isbnList);
}