Processing nodes in a graph one at a time, usually in some specified order.Traversal of a tree is recursively defined to mean visiting the root node and traversing its children.Visiting a node usually involves transforming it in some way or collecting data from it.In "pre-order traversal", a node is visited _before_ its children.In "post-order" traversal, a node is visited _after_ its children.The more rarely used "in-order" traversal is generally applicable only to binary trees, and is where you visit first a node' s left child, then the node itself, and then its right child.For the binary tree:T /I S /D EA pre-order traversal visits the nodes in the order T I D E S. A post-order traversal visits them in the order D E I S T.An in-order traversal visits them in the order D I E T S.(2001-10-01)