Generics and Traits

Rust

Write reusable functions and types with generics, trait bounds and associated types. Learn to read and express the requirements of an API.

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4 articles

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0 / 4 correct

Why can chosen return different iterator types from its two branches, while fixed returns one hidden type?

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fn fixed() -> impl Iterator<Item = u8> {
    0..3
}

fn chosen(reverse: bool) -> Box<dyn Iterator<Item = u8>> {
    if reverse {
        Box::new((0..3).rev())
    } else {
        Box::new(0..3)
    }
}

fn main() {
    println!("{:?}", fixed().collect::<Vec<_>>());
    println!("{:?}", chosen(true).collect::<Vec<_>>());
}

Question 1 of 4