chay.dev
1use std::cmp::Ordering;
2
3#[derive(PartialEq, Debug)]
4enum CreationError {
5 Negative,
6 Zero,
7}
8
9#[derive(PartialEq, Debug)]
10struct PositiveNonzeroInteger(u64);
11
12impl PositiveNonzeroInteger {
13 fn new(value: i64) -> Result<Self, CreationError> {
14 match value.cmp(&0) {
15 Ordering::Less => Err(CreationError::Negative),
16 Ordering::Equal => Err(CreationError::Zero),
17 Ordering::Greater => Ok(Self(value as u64)),
18 }
19 }
20}
21
22fn main() {
23 // You can optionally experiment here.
24}
25
26#[cfg(test)]
27mod tests {
28 use super::*;
29
30 #[test]
31 fn test_creation() {
32 assert_eq!(
33 PositiveNonzeroInteger::new(10),
34 Ok(PositiveNonzeroInteger(10)),
35 );
36 assert_eq!(
37 PositiveNonzeroInteger::new(-10),
38 Err(CreationError::Negative),
39 );
40 assert_eq!(PositiveNonzeroInteger::new(0), Err(CreationError::Zero));
41 }
42}