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Trait4: exercises/traits/traits4.rs
题目
rust
// traits4.rs
//
// Your task is to replace the '??' sections so the code compiles.
//
// Don't change any line other than the marked one.
//
// Execute `rustlings hint traits4` or use the `hint` watch subcommand for a
// hint.
// I AM NOT DONE
pub trait Licensed {
fn licensing_info(&self) -> String {
"some information".to_string()
}
}
struct SomeSoftware {}
struct OtherSoftware {}
impl Licensed for SomeSoftware {}
impl Licensed for OtherSoftware {}
// YOU MAY ONLY CHANGE THE NEXT LINE
fn compare_license_types(software: ??, software_two: ??) -> bool {
software.licensing_info() == software_two.licensing_info()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn compare_license_information() {
let some_software = SomeSoftware {};
let other_software = OtherSoftware {};
assert!(compare_license_types(some_software, other_software));
}
#[test]
fn compare_license_information_backwards() {
let some_software = SomeSoftware {};
let other_software = OtherSoftware {};
assert!(compare_license_types(other_software, some_software));
}
}
您的任务是替换??
部分的代码,以便代码通过编译。
除了标记行以外,不要有任何的修改行为。
题目解析
在这个题目中,我们可以使用特征,而不使用具体的类型作为参数。
rust
fn compare_license_types(software: ??, software_two: ??) -> bool {
fn compare_license_types(software: impl Licensed, software_two: impl Licensed) -> bool {
software.licensing_info() == software_two.licensing_info()
}