Preorder traversal of a binary search tree, without using recursion

Preorder traversal of a binary search tree, without using recursion

void preorderTraversal( Node root )
{
    NodeStack stack = new NodeStack();
    stack.push( root );
    while( true )
    {
        Node curr = stack.pop();
        if( curr == null ) break;
        curr.printValue();
        Node n = curr.getRight();
        if( n != null ) stack.push( n );
        n = curr.getLeft();
        if( n != null ) stack.push( n );
    }
}