Structs

A struct groups related values together under one named type. Unlike a tuple, every field has a name, which makes the code that creates and uses it self-documenting.

main.rs

Try it yourself →

struct Person {
    name: String,
    age: u32,
}

fn main() {
    let alice = Person {
        name: String::from("Alice"),
        age: 30,
    };

    println!("{} is {} years old", alice.name, alice.age);
}

Output

Alice is 30 years old

Methods with impl

An impl block attaches functions to a struct. A method that takes &self borrows the instance it's called on, reading its fields without taking ownership of it — rect.area() below reads width and height without consuming rect.

main.rs

Try it yourself →

struct Rectangle {
    width: u32,
    height: u32,
}

impl Rectangle {
    fn area(&self) -> u32 {
        self.width * self.height
    }
}

fn main() {
    let rect = Rectangle { width: 10, height: 5 };
    println!("Area: {}", rect.area());
}

Output

Area: 50

Next: enums and pattern matching — representing a value that's one of several distinct variants, and match's guarantee that you've handled every one.

Practice exercise

Define a struct Book with fields title: String and price: f64. Add a method total(&self, quantity: u32) -> f64 that returns self.price * quantity as f64. Create a Book with title "Dune" and price 15.0, then print book.total(3).

← Strings and Slices Enums and Pattern Matching →