Euclidean Algorithm in C++

gistfile1.txt

=begin
I found this randomly and wanted to save it for future reference.

Let a, b denote the numerator and denomator, respectively.  Let 'gcd' denote the Greatest Common Divisor of both a and b.
=end

 if(a==0 || b==0)
             return gcd =  1;

        else

             {

                r = (a%b);

                while ( r < 0 || r > 0)

                    {

                        a = b;

                        b = r;

                        r = (a%b);

                    }

                 gcd = b;

              }

         return gcd;

@wanderrful

if(a==0 || b==0)
             return gcd =  1;

The code above returns gcd as 1 if either a or b =0 right?
but please take a look at this:

If k is a non-zero integer, then k divides zero. ... So gcd(k, 0) = gcd(0,k) = k. However, gcd(0, 0) isn't defined. All integers are common divisors of 0 and 0, so there is no greatest one.

source:
http://mfleck.cs.illinois.edu/building-blocks/version-1.0/number-theory.pdf
thank you.