How do you implement traits in Rust?

Question

Accepted Answer

**Trait** — define shared behavior.

**Definition:**
```rust
trait Summary {
    fn summarize(&self) -> String;

// Default implementation
    fn preview(&self) -> String {
        format!("{}...", &self.summarize()[..50])
    }
}
```

**Implementation:**
```rust
struct Article {
    title: String,
    content: String,
}

impl Summary for Article {
    fn summarize(&self) -> String {
        format!("{}: {}", self.title, self.content)
    }
}
```

**Trait bounds:**
```rust
fn notify(item: &impl Summary) {
    println!("Breaking: {}", item.summarize());
}

// Equivalent
fn notify<T: Summary>(item: &T) {
    println!("Breaking: {}", item.summarize());
}
```

**Key:** Traits for shared behavior, bounds for constraints.

Rust: How do you implement traits in Rust?