public IEnumerable <T> Traverse(TraverseOrder order)
{
if (_root == null)
{
throw new InvalidOperationException();
}
var traversal = default(IEnumerable <T>);
switch (order)
{
case TraverseOrder.InOrder:
traversal = _root.TraverseInOrder();
break;
case TraverseOrder.PostOrder:
traversal = _root.TraversePostOrder();
break;
case TraverseOrder.PreOrder:
traversal = _root.TraversePreOrder();
break;
case TraverseOrder.LevelOrder:
traversal = _root.TraverseLevelOrder();
break;
}
return(traversal);
}