Recursive greatest common divisor

Write a recursive function that computes the greatest common divisor of two natural numbers $a$ and $b$ using the fast version of the Euclidean algorithm.

Interface

C++	`int gcd(int a, int b);`
C	`int gcd(int a, int b);`
Java	`public static int gcd(int a, int b);`
Python	`gcd(a, b) # returns int`
	`gcd(a: int, b: int) -> int`

Precondition

Neither $a$ nor $b$ are negative, and at least one of them is strictly greater than zero.

Observation

You only need to submit the required procedure; your main program will be ignored.

Problem information

Author: Unknown
Translator: Carlos Molina

Generation: 2026-09-01T07:40:48.181Z