Ch10 2 Inheritance Vs Composition

// C# - Class-based inheritance
public abstract class Animal
{
    public string Name { get; protected set; }
    public abstract void MakeSound();
    
    public virtual void Sleep()
    {
        Console.WriteLine($"{Name} is sleeping");
    }
}

public class Dog : Animal
{
    public Dog(string name) { Name = name; }
    
    public override void MakeSound()
    {
        Console.WriteLine("Woof!");
    }
    
    public void Fetch()
    {
        Console.WriteLine($"{Name} is fetching");
    }
}

// Interface-based contracts
public interface IFlyable
{
    void Fly();
}

public class Bird : Animal, IFlyable
{
    public Bird(string name) { Name = name; }
    
    public override void MakeSound()
    {
        Console.WriteLine("Tweet!");
    }
    
    public void Fly()
    {
        Console.WriteLine($"{Name} is flying");
    }
}

// Rust - Composition over inheritance with traits
pub trait Animal {
    fn name(&self) -> &str;
    fn make_sound(&self);
    
    // Default implementation (like C# virtual methods)
    fn sleep(&self) {
        println!("{} is sleeping", self.name());
    }
}

pub trait Flyable {
    fn fly(&self);
}

// Separate data from behavior
#[derive(Debug)]
pub struct Dog {
    name: String,
}

#[derive(Debug)]
pub struct Bird {
    name: String,
    wingspan: f64,
}

// Implement behaviors for types
impl Animal for Dog {
    fn name(&self) -> &str {
        &self.name
    }
    
    fn make_sound(&self) {
        println!("Woof!");
    }
}

impl Dog {
    pub fn new(name: String) -> Self {
        Dog { name }
    }
    
    pub fn fetch(&self) {
        println!("{} is fetching", self.name);
    }
}

impl Animal for Bird {
    fn name(&self) -> &str {
        &self.name
    }
    
    fn make_sound(&self) {
        println!("Tweet!");
    }
}

impl Flyable for Bird {
    fn fly(&self) {
        println!("{} is flying with {:.1}m wingspan", self.name, self.wingspan);
    }
}

// Multiple trait bounds (like multiple interfaces)
fn make_flying_animal_sound<T>(animal: &T) 
where 
    T: Animal + Flyable,
{
    animal.make_sound();
    animal.fly();
}