bamch0h https://blog.hatena.ne.jp/bamch0h/ bamchoh’s diary https://bamch0h.hatenablog.com/ Rust Boxでくくって、dyn キーワードをつけるのがミソ trait Animal { fn cry(&self); } struct Dog {} impl Animal for Dog { fn cry(&self) { println!("ワン"); } } struct Cat {} impl Animal for Cat { fn cry(&self) { println!("にゃん"); } } fn new_animal(animal: &str) -> Box<dyn Animal> { if animal == "Dog" { Box::new(Dog{}) } else { B… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fbamch0h.hatenablog.com%2Fentry%2F2022%2F10%2F06%2F230801" title=" トレイトオブジェクトを返す関数の作成 - bamchoh’s diary" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2022-10-06 23:08:01 rich https://bamch0h.hatenablog.com/entry/2022/10/06/230801 1.0 100%