public String toString () {
		// Perform a depth-first search (DFS)
		// with two stacks: one for the nodes (as in the usual DFS)
		// and another, parallel one, for their string prefixes
		//
		// A null on the Node stack means that the corresponding
		// string on the string stack needs to be output
		
		Stack<TernaryTreeNode> nodeStack = new Stack<TernaryTreeNode>();
		Stack<String> prefixStack = new Stack<String>();
		String ret = "";
		
		if (root != null) {
			nodeStack.push(root);
			prefixStack.push("");
			do 
			{
				TernaryTreeNode n = nodeStack.pop();
				String prefix = prefixStack.pop();
				if (n == null) // print the string -- it's complete
				{
					ret+=prefix+"\n";
				} 
				else 
				{
					// Push the right child first, so its popped last,
					// to ensure alphabetical order
					if (n.right != null) 
					{
						nodeStack.push(n.right);
						prefixStack.push(prefix);
					}
					
					// Push the center child, regardless of whether it's null
					// (if it's not null, it needs to be traversed, else it needs
					// to be printed when it's popped off)
					nodeStack.push(n.center);
					prefixStack.push(prefix+n.splitChar);
					
					// Push the left child last, to ensure alphabetical order
					if (n.left != null) 
					{
						nodeStack.push(n.left);
						prefixStack.push(prefix);
					}
				}
			} while (!nodeStack.isEmpty());
		}
		return ret;
	}