Function gcd 

pub const fn gcd(left: u64, right: u64) -> u64

Computes the greatest common divisor of two unsigned integers.

This helper uses the Euclidean algorithm and keeps the required edge cases explicit: gcd(0, 0) == 0 and gcd(a, 0) == a.

Examples

use use_arithmetic::gcd;

assert_eq!(gcd(54, 24), 6);
assert_eq!(gcd(0, 0), 0);
assert_eq!(gcd(21, 0), 21);