Definition: Process all nodes of a tree by processing the root, then recursively processing all subtrees.
Also known as prefix traversal.
Generalization (I am a kind of ...)
tree traversal, depth-first search.
See also in-order traversal, postorder traversal, level-order traversal.
For instance, if the "processing" is just printing, a tree is printed as "root (first subtree) (second subtree) ... (last subtree)." Here is pseudocode for a binary tree:
if tree is null, return;
If you have suggestions, corrections, or comments, please get in touch with Paul E. Black.
Entry modified 14 August 2008.
HTML page formatted Tue Dec 6 16:16:32 2011.
Cite this as:
Paul E. Black, "preorder traversal", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed., U.S. National Institute of Standards and Technology. 14 August 2008. (accessed TODAY) Available from: http://www.nist.gov/dads/HTML/preorderTraversal.html