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Trait1: exercises/traits/traits1.rs

题目

rust
// traits1.rs
//
// Time to implement some traits! Your task is to implement the trait
// `AppendBar` for the type `String`. The trait AppendBar has only one function,
// which appends "Bar" to any object implementing this trait.
//
// Execute `rustlings hint traits1` or use the `hint` watch subcommand for a
// hint.

// I AM NOT DONE

trait AppendBar {
    fn append_bar(self) -> Self;
}

impl AppendBar for String {
    // TODO: Implement `AppendBar` for type `String`.
}

fn main() {
    let s = String::from("Foo");
    let s = s.append_bar();
    println!("s: {}", s);
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn is_foo_bar() {
        assert_eq!(String::from("Foo").append_bar(), String::from("FooBar"));
    }

    #[test]
    fn is_bar_bar() {
        assert_eq!(
            String::from("").append_bar().append_bar(),
            String::from("BarBar")
        );
    }
}

这次来实现一些Trait,您的任务是为String类型实现AppendBar Trait。这个Trait只有一个函数,它将Bar字符串追加到实现此Trait的任何对象后面。

题目解析

rust
trait AppendBar {
    fn append_bar(self) -> Self;
}

impl AppendBar for String {
    // TODO: Implement `AppendBar` for type `String`.
    fn append_bar(self) -> Self { 
        self + "Bar" 
    } 
}

参考资料

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