mirror of
https://github.com/notohh/rustlings.git
synced 2024-11-29 00:34:17 -05:00
feat: add rc1.rs exercise
This commit is contained in:
parent
c791cf4232
commit
ce86d252e5
2 changed files with 112 additions and 0 deletions
98
exercises/standard_library_types/rc1.rs
Normal file
98
exercises/standard_library_types/rc1.rs
Normal file
|
@ -0,0 +1,98 @@
|
|||
// rc1.rs
|
||||
// In this exercise, we want to express the concept of multiple owners via the Rc<T> type.
|
||||
// This is a model of our solar system - there is a Sun type and multiple Planets.
|
||||
// The Planets take ownership of the sun, indicating that they revolve around the sun.
|
||||
|
||||
// Make this code compile by using the proper Rc primitives to express that the sun has multiple owners.
|
||||
|
||||
// I AM NOT DONE
|
||||
use std::rc::Rc;
|
||||
|
||||
#[derive(Debug)]
|
||||
struct Sun {}
|
||||
|
||||
#[derive(Debug)]
|
||||
enum Planet {
|
||||
Mercury(Rc<Sun>),
|
||||
Venus(Rc<Sun>),
|
||||
Earth(Rc<Sun>),
|
||||
Mars(Rc<Sun>),
|
||||
Jupiter(Rc<Sun>),
|
||||
Saturn(Rc<Sun>),
|
||||
Uranus(Rc<Sun>),
|
||||
Neptune(Rc<Sun>),
|
||||
}
|
||||
|
||||
impl Planet {
|
||||
fn details(&self) {
|
||||
println!("Hi from {:?}!", self)
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {
|
||||
let sun = Rc::new(Sun {});
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference
|
||||
|
||||
let mercury = Planet::Mercury(Rc::clone(&sun));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 2 references
|
||||
mercury.details();
|
||||
|
||||
let venus = Planet::Venus(Rc::clone(&sun));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 3 references
|
||||
venus.details();
|
||||
|
||||
let earth = Planet::Earth(Rc::clone(&sun));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 4 references
|
||||
earth.details();
|
||||
|
||||
let mars = Planet::Mars(Rc::clone(&sun));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 5 references
|
||||
mars.details();
|
||||
|
||||
let jupiter = Planet::Jupiter(Rc::clone(&sun));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 6 references
|
||||
jupiter.details();
|
||||
|
||||
// TODO
|
||||
let saturn = Planet::Saturn(Rc::new(Sun {}));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 7 references
|
||||
saturn.details();
|
||||
|
||||
// TODO
|
||||
let uranus = Planet::Uranus(Rc::new(Sun {}));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 8 references
|
||||
uranus.details();
|
||||
|
||||
// TODO
|
||||
let neptune = Planet::Neptune(Rc::new(Sun {}));
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 9 references
|
||||
neptune.details();
|
||||
|
||||
assert_eq!(Rc::strong_count(&sun), 9);
|
||||
|
||||
drop(neptune);
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 8 references
|
||||
|
||||
drop(uranus);
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 7 references
|
||||
|
||||
drop(saturn);
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 6 references
|
||||
|
||||
drop(jupiter);
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 5 references
|
||||
|
||||
drop(mars);
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 4 references
|
||||
|
||||
// TODO
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 3 references
|
||||
|
||||
// TODO
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 2 references
|
||||
|
||||
// TODO
|
||||
println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference
|
||||
|
||||
assert_eq!(Rc::strong_count(&sun), 1);
|
||||
}
|
14
info.toml
14
info.toml
|
@ -929,6 +929,20 @@ is too much of a struggle, consider reading through all of Chapter 16 in the boo
|
|||
https://doc.rust-lang.org/stable/book/ch16-00-concurrency.html
|
||||
"""
|
||||
|
||||
[[exercises]]
|
||||
name = "rc1"
|
||||
path = "exercises/standard_library_types/rc1.rs"
|
||||
mode = "compile"
|
||||
hint = """
|
||||
This is a straightforward exercise to use the Rc<T> type. Each Planet has
|
||||
ownership of the Sun, and uses Rc::clone() to increment the reference count of the Sun.
|
||||
After using drop() to move the Planets out of scope individually, the reference count goes down.
|
||||
In the end the sun only has one reference again, to itself. See more at:
|
||||
https://doc.rust-lang.org/book/ch15-04-rc.html
|
||||
|
||||
* Unforunately Pluto is no longer considered a planet :(
|
||||
"""
|
||||
|
||||
# THREADS
|
||||
|
||||
[[exercises]]
|
||||
|
|
Loading…
Reference in a new issue