How can I inherit methods for a struct containing another one - rust

Question

I am from C++ background and very new to rust. I have the following code which I have written to understand the code reusability, which is the sole purpose behind inheritance.
/* in animal.rs */
//declare Animal here
pub struct Animal;
// implement Animal here
impl Animal
{
pub fn breathe(&self)
{
println!("All animals breathe!");
}
}
// declare Dog here
pub struct Dog
{
pub parent: Animal
}
// implement Dog here
impl Dog
{
pub fn bark(&self)
{
println!("Dogs bark!");
}
pub fn breathe(&self)
{
self.parent.breathe();
}
}
/* in main.rs */
mod animal;
fn main()
{
let d = animal::Dog {parent : animal::Animal};
d.bark();
d.breathe();
}
If I don't implement the breathe function in Dog the compiler doesn't find it. In C++ the child inherits the functions from its parent. Can someone explain it?
Additional question: Can someone show some example code how dynamic/late binding works in rust. In C++ it is achieved by virtual functions.

Answer 1

There is no struct inheritance in Rust but you can use trait like in the following example to define a shared behavior. And you can see dyn AnimalTrait keyword which is used for dynamic dispatch in Rust.
trait AnimalTrait {
fn is_canine(&self) -> String {
return String::from("canine");
}
}
pub struct Dog;
impl AnimalTrait for Dog {}
pub struct Cat;
impl AnimalTrait for Cat {}
pub struct Mouse;
impl AnimalTrait for Mouse {
fn is_canine(&self) -> String {
return String::from("not canine");
}
}
fn main() {
let (d, c, m) = (Dog {}, Cat {}, Mouse {});
let all_animals: Vec<Box<dyn AnimalTrait>> = vec![Box::new(d), Box::new(c), Box::new(m)];
for e in all_animals {
match e.is_canine().as_str() {
"canine" => println!("I can tear apart well."),
"not canine" => println!("I will have hard time tearing apart."),
_ => (),
}
}
}