Can't Euler's version of gcd be tail-recursive?

[klaeufer]

https://github.com/LoyolaChicagoBooks/introcs-scala-examples/blob/master/gcd/gcd.scala#L5

There is a more general tail-recursive version here, as well as a simpler one for positive arguments:

http://en.wikipedia.org/wiki/Greatest_common_divisor#Using_Euclid.27s_algorithm

[gkthiruvathukal]

Thanks for suggesting this. The original C# version was designed only for positive (well, non-negative, because you do have a base case at x=0) inputs. Technically, this might be more true to Euclid's original algorithm.