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rc1 solution

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This commit is contained in:
mo8it
2024-06-29 01:20:59 +02:00
parent 61c7eaed62
commit f3842aa746
3 changed files with 115 additions and 15 deletions
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21
exercises/19_smart_pointers/rc1.rs
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@@ -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();