gcd_/
lib.rs

1pub fn gcd(mut first: i128, mut second: i128) -> Result<i128, &'static str> {
2    if first < 0 || second < 0 {
3        return Err("Error, None of the numbers can be negative.");
4    }
5    if first < second {
6        let cash: i128 = first;
7        first = second;
8        second = cash;
9    }
10    if second == 0 {
11        return Ok(first);
12    }
13    gcd(second, first % second)
14}
15
16#[cfg(test)]
17mod tests {
18    use super::*;
19
20    #[test]
21    fn it_works() {
22        let mut result: i128 = gcd(6, 18).unwrap();
23        assert_eq!(result, 6);
24
25        result = gcd(24, 4).unwrap();
26        assert_eq!(result, 4);
27
28        let result = gcd(-10, 10);
29        assert!(result.is_err())
30    }
31}
gcd_/lib.rs

gcd_/
lib.rs
