Sometimes, the Rust compiler cannot determine the size of a trait object at compile time. For example, if a function returns a trait object based on a condition, in such cases, impl Trait
is not going to work. This is because the size of the trait object is not known at compile time. In such cases, you can use Box<dyn Trait>
to return a trait object.
Box<T>
lets you allocate memory on the heap and store the value of T
in that memory. Box<dyn Trait>
is a trait object that allows you to store a value of any type that implements Trait
in the heap.
This is called dynamic dispatch because the method to call is determined at runtime, not at compile time. This is in contrast to static dispatch, where the method to call is determined at compile time.
You need to define a function that returns a Box<dyn Speakable>
based on a condition.
Here is what you need to do:
Speakable
trait with a method speak
that returns a String
.Dog
with two fields: name
and breed
, both of type String
.Speakable
trait for Dog
to return a string Woof
.Robot
with two fields: model
and purpose
, both of type String
.Speakable
trait for Robot
to return a string Beep boop
.get_speaker
that takes a &str
parameter and returns either a Dog
or a Robot
based on the parameter.dog
or robot
.pub trait Speakable { fn speak(&self)-> String;}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String,}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog::default()) } "robot" => { Box::new(Robot::default()) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_owned() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_owned() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog{ name: "".to_string(), breed: "".to_string() }), "robot" => Box::new(Robot{ model: "".to_string(), purpose: "".to_string() }), _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_owned() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_owned() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog{ name: "".to_owned(), breed: "".to_owned() }), "robot" => Box::new(Robot{ model: "".to_owned(), purpose: "".to_owned() }), _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_owned() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_owned() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog{ name: "".to_owned(), breed: "".to_owned() }), "robot" => Box::new(Robot{ model: "".to_owned(), purpose: "".to_owned() }), _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { breed: "frenchie".to_string(), name: "bill".to_string() }) } "robot" => { Box::new(Robot { model: "deepseek".to_string(), purpose: "coding".to_string() }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}pub trait Speakable { fn speak(&self) -> String;}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog{name: String::from("Max"), breed: String::from("German Shepherd")}) } "robot" => { // Return a Robot instance here Box::new(Robot{model: String::from("H1234"), purpose: String::from("house helper")}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog {name: "Cat".to_string(), breed: "Mix".to_string()}) } "robot" => { // Return a Robot instance here Box::new(Robot {model: "T-800".to_string(), purpose: "Be back".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog { name : "Wuffi".to_string(), breed : "Doggi".to_string(), }), "robot" => Box::new(Robot { // Return a Robot instance here model: "HAL2001".to_string(), purpose: "destroy".to_string(), }), _ => panic!("Unknown speaker type"), }}pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { name: String::default(), breed: String::default() } ) // Return a Dog instance here } "robot" => { Box::new(Robot{model: String::default(), purpose: String::default()}) // Return a Robot instance here } _ => panic!("Unknown speaker type"), }}pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here let dog = Dog { name: String::from("Doggy"), breed: String::from("Doggy"), }; Box::new(dog) } "robot" => { // Return a Robot instance here let robot = Robot { model: String::from("Robby"), purpose: String::from("Robby"), }; Box::new(robot) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String}pub struct Robot{ pub model: String, pub purpose: String}impl Speakable for Dog { fn speak(&self) -> String { return "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { return "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { return Box::new(Dog{name: String::default() , breed: String::default()}) } "robot" => { return Box::new(Robot{model: String::default() , purpose: String::default()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String}impl Speakable for Dog { fn speak(&self) -> String { format!("Woof") }}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> String { format!("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog{ name: "bobby".to_string(), breed:"terrier".to_string()}) } "robot" => { Box::new(Robot { model:"1".to_string(), purpose:"destroy".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: String::from("a"), breed: String::from("b") }) } "robot" => { // Return a Robot instance here Box::new(Robot { model: String::from("c"), purpose: String::from("d") }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog::default()) // Return a Dog instance here } "robot" => { Box::new(Robot::default()) // Return a Robot instance here } _ => panic!("Unknown speaker type"), }}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String}pub trait Speakable { fn speak(&self) -> String;}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> &'static str;}pub struct Dog { pub name: String, pub breed: String}impl Speakable for Dog { fn speak(&self) -> &'static str { return "Woof"; }}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> &'static str { "Beep boop" }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog{name: "x".to_string(), breed: "y".to_string()}) } "robot" => { // Return a Robot instance here Box::new(Robot{ model: "x".to_string(), purpose: "y".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}pub trait Speakable { fn speak(&self) -> String;}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { name: "vaya".to_string(), breed: "Colley".to_string(), }) } "robot" => { Box::new(Robot { model: "r2d2".to_string(), purpose: "repair ship".to_string(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: String::new(), breed: String::new(), }) } "robot" => { // Return a Robot instance here Box::new(Robot { model: String::new(), purpose: String::new(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog { name: String::new(), breed: String::new(), }), "robot" => { // Return a Robot instance here Box::new(Robot { model: String::new(), purpose: String::new(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { format!("Woof") }}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { format!("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog::default()) } "robot" => { Box::new(Robot::default()) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String }impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog{ breed: String::from("JRT"), name: "Mayo".to_owned() }) // Return a Dog instance here } "robot" => { Box::new(Robot { model: String::from("T1000"), purpose: "Pass the butter".to_owned() }) // Return a Robot instance here } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog {name: "juju".to_string(), breed: "labrador".to_string()}) } "robot" => { Box::new(Robot {model: "model1".to_string(), purpose: "cleaning".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { name: "Max".to_string(), breed: "Labrador".to_string(), }) } "robot" => { Box::new(Robot { model: "ABC-500".to_string(), purpose: "protect".to_string(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable{ fn speak(&self)->String;}pub struct Dog{ pub name: String, pub breed: String}impl Speakable for Dog{ fn speak(&self)->String{ "Woof".to_string() }}pub struct Robot{ pub model: String, pub purpose: String}impl Speakable for Robot{ fn speak(&self)->String{ "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog{ name: "fox".to_string(), breed: "idk".to_string() }) } "robot" => { Box::new(Robot{ model: "fox".to_string(), purpose: "idk".to_string() }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_owned() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_owned() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: "a".to_owned(), breed: "b".to_owned(), }) } "robot" => { // Return a Robot instance here Box::new(Robot { model: "c".to_owned(), purpose: "d".to_owned(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new( Dog { name: "name".to_string(), breed: "breed".to_string() } ) } "robot" => { Box::new( Robot { model: "model".to_string(), purpose: "purpose".to_string() } ) } _ => panic!("Unknown speaker type"), }}pub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog { name: "name".to_string(), breed: "breed".to_string(), }), "robot" => Box::new(Robot { model: "model".to_string(), purpose: "purpose".to_string(), }), _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
#[derive(Default)]pub struct Dog{ pub name: String, pub breed: String,}pub trait Speakable{ fn speak(&self) -> String;}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String{ "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog::default()) } "robot" => { Box::new(Robot::default()) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog::default()) } "robot" => { // Return a Robot instance here Box::new(Robot::default()) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog::default()) } "robot" => { // Return a Robot instance here Box::new(Robot::default()) } _ => panic!("Unknown speaker type"), }}pub trait Speakable { fn speak(&self) -> String;}#[derive(Debug, Default)]pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".into() }}#[derive(Debug, Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".into() }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { name: "".to_string(), breed: "".to_string()}) } "robot" => { Box::new(Robot { model: "".to_string(), purpose: "".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> &'static str;}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> &'static str { "Woof" }}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> &'static str { "Beep boop" }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog::default()) } "robot" => { // Return a Robot instance here Box::new(Robot::default()) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: "Scooby".to_string(), breed: "Doo".to_string()}) } "robot" => { // Return a Robot instance here Box::new(Robot { model: "Bender".to_string(), purpose: "drink".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog::default()) } "robot" => { Box::new(Robot::default()) // Return a Robot instance here } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}#[derive(Debug, Default)]pub struct Dog { pub name: String, pub breed: String,}#[derive(Debug, Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog::default()), "robot" => Box::new(Robot::default()), _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".into() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".into() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { breed: "Dog".into(), name: "Alpha".into(), }) } "robot" => { Box::new(Robot { model: "Model".into(), purpose: "Robot".into(), }) } _ => panic!("Unknown speaker type"), }}pub trait Speakable { fn speak(&self) -> String;}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Dog { fn speak(&self) -> String { "Woof".into() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".into() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance Box::new(Dog{ name: "a".into(), breed: "b".into() }) } "robot" => { // Return a Robot instance here Box::new(Robot{ model: "rn".into(), purpose: "aaaa".into() }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog::new("fido".to_string(), "mix".to_string())) } "robot" => { // Return a Robot instance here Box::new(Robot::new("01".to_string(), "breed".to_string())) } _ => panic!("Unknown speaker type"), }}pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Dog { fn new(name: String, breed: String) -> Dog { Dog{name, breed} }}impl Robot { fn new(model: String, purpose: String) -> Robot { Robot{model, purpose} } }impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog{ name: "Rex".to_string(), breed: "Golden Retriever".to_string(), }) } "robot" => { // Return a Robot instance here Box::new(Robot{ model: "R2D2".to_string(), purpose: "Exploration".to_string(), }) } _ => panic!("Unknown speaker type"), }}pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable{ fn speak(&self) -> String;}pub struct Dog{ pub name: String, pub breed: String}impl Speakable for Dog{ fn speak(&self) -> String{ return String::from("Woof"); }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot{ fn speak(&self) -> String { return String::from("Beep boop"); }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { name: "".to_string(), breed: "".to_string(), }) } "robot" => { Box::new(Robot { model: "".to_string(), purpose: "".to_string(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> &'static str;}#[derive(Default)]pub struct Dog { pub name: String, pub breed: String}impl Speakable for Dog { fn speak(&self) -> &'static str { "Woof" }}#[derive(Default)]pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> &'static str { "Beep boop" }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { ..Default::default() }) } "robot" => { Box::new(Robot { ..Default::default() }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: "".to_string(), breed: "".to_string(), }) } "robot" => { // Return a Robot instance here Box::new(Robot { model: "".to_string(), purpose: "".to_string(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog {name: "".to_string(), breed: "".to_string()}) } "robot" => { Box::new(Robot {model: "".to_string(), purpose: "".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog { name: "Snacky".to_string(), breed: "Golden Retriever".to_string(), }), "robot" => Box::new(Robot { model: "Bishop / HS17B48XG5-D5".to_string(), purpose: "The android executive officer assigned to the Sulaco".to_string(), }), _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: "Bella".to_string(), breed: "Chow-chow".to_string() }) } "robot" => { // Return a Robot instance here Box::new(Robot { model: "C3P0".to_string(), purpose: "Diplomacy".to_string() }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog{name:"Rex".to_string(), breed:"Doberman".to_string()}) } "robot" => { // Return a Robot instance here Box::new(Robot{model:"Claude".to_string(), purpose:"General".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog{ pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".into() }}pub struct Robot{ pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".into() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog{name:"Rex".to_string(), breed:"Doberman".to_string()}) } "robot" => { // Return a Robot instance here Box::new(Robot{model:"".to_string(), purpose:"".to_string()}) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog{ pub name: String, pub breed: String}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}pub struct Robot { pub model: String, pub purpose: String}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog { name: String::from(""), breed:String::from("") }) } "robot" => { Box::new(Robot { model: String::from(""), purpose: String::from("") }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}pub trait Speakable { fn speak(&self) -> String;}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { Box::new(Dog{ name: "Rex".to_string(), breed: "German Shepeard".to_string(), }) } "robot" => { Box::new(Robot{ model: "Robot1".to_string(), purpose: "To kill".to_string(), }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub trait Speakable { fn speak(&self) -> String;}pub struct Dog { pub name: String, pub breed: String,}impl Speakable for Dog { fn speak(&self) -> String { "Woof".to_string() }}pub struct Robot { pub model: String, pub purpose: String,}impl Speakable for Robot { fn speak(&self) -> String { "Beep boop".to_string() }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => Box::new(Dog { name: "Buddy".to_string(), breed: "Golden Retriever".to_string(), }), "robot" => Box::new(Robot { model: "RX-78".to_string(), purpose: "Companion".to_string(), }), _ => panic!("Unknown speaker type"), }}fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}
pub struct Dog { pub name: String, pub breed: String,}pub struct Robot { pub model: String, pub purpose: String,}pub trait Speakable { fn speak(&self) -> String;}impl Speakable for Dog { fn speak(&self) -> String { String::from("Woof") }}impl Speakable for Robot { fn speak(&self) -> String { String::from("Beep boop") }}pub fn get_speaker(kind: &str) -> Box<dyn Speakable> { match kind { "dog" => { // Return a Dog instance here Box::new(Dog { name: String::from("Doggo"), breed: String::from("Chihuahua") }) } "robot" => { // Return a Robot instance here Box::new(Robot { model: String::from("R2D2"), purpose: String::from("Cleaning") }) } _ => panic!("Unknown speaker type"), }}// Example usagepub fn main() { let dog_speaker = get_speaker("dog"); println!("{}", dog_speaker.speak()); // Expected output: Woof let robot_speaker = get_speaker("robot"); println!("{}", robot_speaker.speak()); // Expected output: Beep boop}