mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-25 00:03:43 +00:00
26 lines
505 B
Rust
26 lines
505 B
Rust
// run-pass
|
|
|
|
trait DigitCollection: Sized {
|
|
type Iter: Iterator<Item = u8>;
|
|
fn digit_iter(self) -> Self::Iter;
|
|
|
|
fn digit_sum(self) -> u32 {
|
|
self.digit_iter()
|
|
.map(|digit: u8| digit as u32)
|
|
.fold(0, |sum, digit| sum + digit)
|
|
}
|
|
}
|
|
|
|
impl<I> DigitCollection for I where I: Iterator<Item=u8> {
|
|
type Iter = I;
|
|
|
|
fn digit_iter(self) -> I {
|
|
self
|
|
}
|
|
}
|
|
|
|
fn main() {
|
|
let xs = vec![1, 2, 3, 4, 5];
|
|
assert_eq!(xs.into_iter().digit_sum(), 15);
|
|
}
|