# Class 19: Tail Recursion

Back to Recursion Basics. On to Recursion, Revisited.

This outline is also available in PDF.

Held: Monday, 1 October 2007

Summary: Today we consider a particular kind of recursion, tail recursion. A tail recursive procedure is one that returns recursive results directly, without further processing. We study tail recursion primarily because a common technique for making a procedure tail recursive is also helpful in other circumstances.

Related Pages:

Notes:

• Extra credit (EC) for attending today's Mathematics and Statistics Student Seminar.
• The President's Office scheduled me for a meeting at 1pm today (and another at 2:30 pm), so no office hours today, and I will be unavailable this afternoon.
• Reading for tomorrow: Recursion, Revisited.

Overview:

• The key idea of recursion.
• A new technique: Passing along intermediate results.
• Special case: Tail recursion.

Back to Recursion Basics. On to Recursion, Revisited.

Disclaimer: I usually create these pages on the fly, which means that I rarely proofread them and they may contain bad grammar and incorrect details. It also means that I tend to update them regularly (see the history for more details). Feel free to contact me with any suggestions for changes.

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Samuel A. Rebelsky, rebelsky@grinnell.edu

Copyright © 2007 Janet Davis, Matthew Kluber, and Samuel A. Rebelsky. (Selected materials copyright by John David Stone and Henry Walker and used by permission.) This material is based upon work partially supported by the National Science Foundation under Grant No. CCLI-0633090. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License. To view a copy of this license, visit `http://creativecommons.org/licenses/by-nc/2.5/` or send a letter to Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 94105, USA.