Implementing Traits

trait Pet {
    fn talk(&self) -> String;

    fn greet(&self) {
        println!("Oh you're a cutie! What's your name? {}",;

struct Dog {
    name: String,
    age: i8,

impl Pet for Dog {
    fn talk(&self) -> String {
        format!("Woof, my name is {}!",

fn main() {
    let fido = Dog { name: String::from("Fido"), age: 5 };
  • To implement Trait for Type, you use an impl Trait for Type { .. } block.

  • Unlike Go interfaces, just having matching methods is not enough: a Cat type with a talk() method would not automatically satisfy Pet unless it is in an impl Pet block.

  • Traits may provide default implementations of some methods. Default implementations can rely on all the methods of the trait. In this case, greet is provided, and relies on talk.