The following technique is known as Euclid's Algorithm because it appears in Euclid's Elements (Book 7, ca. 300 BC). It may be the oldest nontrivial...

implies that the GCD of 36 and 20 is 4. It can be shown that for any two starting numbers, this repeated reduction eventually produces a pair where the second number is 0. Then the GCD is the other number in the pair.

Write a method called gcd that takes two integer parameters and that uses Euclid’s algorithm to compute and return the greatest common divisor of the two numbers.