Trait Basics and Implementation

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Trait Basics and Implementation

Traits define shared behavior that multiple types can implement. They are similar to interfaces in other languages. The dyn keyword creates a trait object for dynamic dispatch. Traits enable polymorphism and code reuse across different types.

snippet.rs
rust
trait Summable {
    fn sum(&self) -> i32;
}
 
struct Point {
    x: i32,
    y: i32,
}
 
impl Summable for Point {
    fn sum(&self) -> i32 {
        self.x + self.y
    }
}
 
fn total(items: &[&dyn Summable]) -> i32 {
    items.iter().map(|p| p.sum()).sum()
}
 
fn main() {
    let p1 = Point { x: 3, y: 4 };
    let p2 = Point { x: 5, y: 6 };
    println!("Total: {}", total(&[&p1, &p2]));
}

Breakdown

trait Summable { ... }

Defines a trait with one required method signature

impl Summable for Point { ... }

Implements the trait for the Point struct

&[&dyn Summable]

Reference to slice of trait objects for dynamic dispatch

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