GCD Exercise

[Michael Catanzaro]

There appears to be a problem with the GCD exercise in the chapter on functions: http://www.itmaybeahack.com/book/python-2.6/html/p01/p01c09_functions.html#function-exercises

This algorithm is an infinite loop - trace with p=4, q=2 to see why.

From your iterative version, the third step should be: if p > q, return GCD(p-q, q)

Thanks for the free book. :-)