Why traits are used in Rust - See It in Action

Why traits are used

📖 Scenario: Imagine you are building a program that handles different types of animals. Each animal can make a sound, but the way they make sounds is different. You want a way to tell your program that all animals can make a sound, without writing the same code for each animal.

🎯 Goal: You will create a trait called AnimalSound that defines a behavior for making a sound. Then, you will implement this trait for different animal types. Finally, you will call the sound method on each animal to see their unique sounds.

📋 What You'll Learn

Create a trait called AnimalSound with a method make_sound

Create two structs: Dog and Cat

Implement the AnimalSound trait for both Dog and Cat

Call the make_sound method for both animals and print the results

💡 Why This Matters

🌍 Real World

Traits are used in Rust to define common behaviors for different types, like animals making sounds or shapes calculating area.

💼 Career

Understanding traits is essential for Rust programming jobs, as they enable writing clean, modular, and maintainable code.

1

Create the structs for animals

Create two structs called Dog and Cat with no fields.

Rust

# Your code here

Hint

Use struct Dog; and struct Cat; to define empty structs.

2

Create the trait AnimalSound

Create a trait called AnimalSound with a method make_sound that returns a &str.

Rust

struct Dog;
struct Cat;

# Your code here

Hint

Define the trait with trait AnimalSound { fn make_sound(&self) -> &str; }.

3

Implement the trait for Dog and Cat

Implement the AnimalSound trait for Dog and Cat. For Dog, make_sound should return "Bark". For Cat, it should return "Meow".

Rust

struct Dog;
struct Cat;

trait AnimalSound {
    fn make_sound(&self) -> &str;
}

# Your code here

Hint

Use impl AnimalSound for Dog and impl AnimalSound for Cat with the method returning the correct sounds.

4

Call the make_sound method and print results

Create instances of Dog and Cat. Call their make_sound methods and print the results using println!.

Rust

struct Dog;
struct Cat;

trait AnimalSound {
    fn make_sound(&self) -> &str;
}

impl AnimalSound for Dog {
    fn make_sound(&self) -> &str {
        "Bark"
    }
}

impl AnimalSound for Cat {
    fn make_sound(&self) -> &str {
        "Meow"
    }
}

// Your code here

Hint

Create dog and cat variables, then print their sounds with println!("Dog says: {}", dog.make_sound()).