diff options
| -rw-r--r-- | exercises/19_smart_pointers/rc1.rs | 21 | ||||
| -rw-r--r-- | rustlings-macros/info.toml | 4 | ||||
| -rw-r--r-- | solutions/19_smart_pointers/rc1.rs | 105 |
3 files changed, 115 insertions, 15 deletions
diff --git a/exercises/19_smart_pointers/rc1.rs b/exercises/19_smart_pointers/rc1.rs index 19de3db..ecd3438 100644 --- a/exercises/19_smart_pointers/rc1.rs +++ b/exercises/19_smart_pointers/rc1.rs @@ -1,15 +1,12 @@ // 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. +// `Rc<T>` type. This is a model of our solar system - there is a `Sun` type and +// multiple `Planet`s. The planets take ownership of the sun, indicating that +// they revolve around the sun. use std::rc::Rc; #[derive(Debug)] -struct Sun {} +struct Sun; #[derive(Debug)] enum Planet { @@ -25,7 +22,7 @@ enum Planet { impl Planet { fn details(&self) { - println!("Hi from {:?}!", self) + println!("Hi from {self:?}!"); } } @@ -39,7 +36,7 @@ mod tests { #[test] fn rc1() { - let sun = Rc::new(Sun {}); + let sun = Rc::new(Sun); println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference let mercury = Planet::Mercury(Rc::clone(&sun)); @@ -63,17 +60,17 @@ mod tests { jupiter.details(); // TODO - let saturn = Planet::Saturn(Rc::new(Sun {})); + 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 {})); + 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 {})); + let neptune = Planet::Neptune(Rc::new(Sun)); println!("reference count = {}", Rc::strong_count(&sun)); // 9 references neptune.details(); diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml index 744ad08..5b3f781 100644 --- a/rustlings-macros/info.toml +++ b/rustlings-macros/info.toml @@ -993,11 +993,11 @@ of the `Sun`. After using `drop()` to move the `Planet`s out of scope individually, the reference count goes down. -In the end the `Sun` only has one reference again, to itself. +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 -* Unfortunately Pluto is no longer considered a planet :(""" +Unfortunately, Pluto is no longer considered a planet :(""" [[exercises]] name = "arc1" diff --git a/solutions/19_smart_pointers/rc1.rs b/solutions/19_smart_pointers/rc1.rs index 4e18198..c0a41ab 100644 --- a/solutions/19_smart_pointers/rc1.rs +++ b/solutions/19_smart_pointers/rc1.rs @@ -1 +1,104 @@ -// Solutions will be available before the stable release. Thank you for testing the beta version 🥰 +// 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 `Planet`s. The planets take ownership of the sun, indicating that +// they revolve around the sun. + +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() { + // You can optionally experiment here. +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn rc1() { + 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(); + + let saturn = Planet::Saturn(Rc::clone(&sun)); + println!("reference count = {}", Rc::strong_count(&sun)); // 7 references + saturn.details(); + + // TODO + let uranus = Planet::Uranus(Rc::clone(&sun)); + println!("reference count = {}", Rc::strong_count(&sun)); // 8 references + uranus.details(); + + // TODO + let neptune = Planet::Neptune(Rc::clone(&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 + + drop(earth); + println!("reference count = {}", Rc::strong_count(&sun)); // 3 references + + drop(venus); + println!("reference count = {}", Rc::strong_count(&sun)); // 2 references + + drop(mercury); + println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference + + assert_eq!(Rc::strong_count(&sun), 1); + } +} |