From a8fd315e099e4b5c24b450eb6ba6ec3cccd96854 Mon Sep 17 00:00:00 2001 From: seporterfield <107010978+seporterfield@users.noreply.github.com> Date: Sun, 1 Jan 2023 01:52:47 +0100 Subject: moved rc to smart_pointers --- exercises/smart_pointers/rc1.rs | 98 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 exercises/smart_pointers/rc1.rs (limited to 'exercises/smart_pointers') diff --git a/exercises/smart_pointers/rc1.rs b/exercises/smart_pointers/rc1.rs new file mode 100644 index 0000000..9b907fd --- /dev/null +++ b/exercises/smart_pointers/rc1.rs @@ -0,0 +1,98 @@ +// rc1.rs +// In this exercise, we want to express the concept of multiple owners via the Rc 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), + Venus(Rc), + Earth(Rc), + Mars(Rc), + Jupiter(Rc), + Saturn(Rc), + Uranus(Rc), + Neptune(Rc), +} + +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); +} -- cgit v1.2.3