To explain them, not just list them, would take a short amount of time. The only difference between In-order, Post-order, and Pre-order is where the node is printed in the function. In order: traverse(node.left_chld) print(node.value) traverse(node.right_child) post-order: traverse(node.left_chld) traverse(node.right_child) print(node.value) pre-order: print(node.value) traverse(node.left_chld) traverse(node.right_child) level order is what is called breadth first search. Ideally you would use a queue and you'd do something like: levelorder(root) q = empty queue q.enqueue(root) while not q.empty do node << q.dequeue() visit(node) if node.left != null q.enqueue(node.left) if node.right != null q.enqueue(node.right) (adapted the last snippet from Wikipedia)