Complete thread1 and thread2

exercises/19_smart_pointers/arc1.rs

@@ -21,19 +21,17 @@
 //
 // Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
 use std::thread;
 
 fn main() {
     let numbers: Vec<_> = (0..100u32).collect();
-    let shared_numbers = // TODO
+    let shared_numbers = Arc::new(numbers); // TODO
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
-        let child_numbers = // TODO
+        let child_numbers = Arc::clone(&shared_numbers); // TODO
         joinhandles.push(thread::spawn(move || {
             let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);

exercises/19_smart_pointers/box1.rs

@@ -18,11 +18,9 @@
 //
 // Execute `rustlings hint box1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 pub enum List {
-    Cons(i32, List),
+    Cons(i32, Box<List>),
     Nil,
 }
 
@@ -35,11 +33,11 @@ fn main() {
 }
 
 pub fn create_empty_list() -> List {
-    todo!()
+    List::Nil
 }
 
 pub fn create_non_empty_list() -> List {
-    todo!()
+    List::Cons(3, Box::new(List::Nil))
 }
 
 #[cfg(test)]

exercises/19_smart_pointers/cow1.rs

@@ -12,8 +12,6 @@
 //
 // Execute `rustlings hint cow1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::borrow::Cow;
 
 fn abs_all<'a, 'b>(input: &'a mut Cow<'b, [i32]>) -> &'a mut Cow<'b, [i32]> {
@@ -49,6 +47,8 @@ mod tests {
         let mut input = Cow::from(&slice[..]);
         match abs_all(&mut input) {
             // TODO
+            Cow::Borrowed(_) => Ok(()),
+            _ => Err("Expected a reference I suppose?"),
         }
     }
 
@@ -61,6 +61,8 @@ mod tests {
         let mut input = Cow::from(slice);
         match abs_all(&mut input) {
             // TODO
+            Cow::Owned(_) => Ok(()),
+            _ => Err("Expected owned value"),
         }
     }
 
@@ -73,6 +75,8 @@ mod tests {
         let mut input = Cow::from(slice);
         match abs_all(&mut input) {
             // TODO
+            Cow::Owned(_) => Ok(()),
+            _ => Err("Expected owned value"),
         }
     }
 }

exercises/19_smart_pointers/rc1.rs

@@ -10,8 +10,6 @@
 //
 // Execute `rustlings hint rc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::rc::Rc;
 
 #[derive(Debug)]
@@ -61,17 +59,17 @@ fn main() {
     jupiter.details();
 
     // TODO
-    let saturn = Planet::Saturn(Rc::new(Sun {}));
+    let saturn = Planet::Saturn(Rc::clone(&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::clone(&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::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 9 references
     neptune.details();
 
@@ -93,12 +91,15 @@ fn main() {
     println!("reference count = {}", Rc::strong_count(&sun)); // 4 references
 
     // TODO
+    drop(earth);
     println!("reference count = {}", Rc::strong_count(&sun)); // 3 references
 
     // TODO
+    drop(venus);
     println!("reference count = {}", Rc::strong_count(&sun)); // 2 references
 
     // TODO
+    drop(mercury);
     println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference
 
     assert_eq!(Rc::strong_count(&sun), 1);

exercises/20_threads/threads1.rs

@@ -8,24 +8,25 @@
 // Execute `rustlings hint threads1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::thread;
 use std::time::{Duration, Instant};
 
+fn thread_func(i: u32) -> u128 {
+    let start = Instant::now();
+    thread::sleep(Duration::from_millis(250));
+    println!("thread {} is complete", i);
+    start.elapsed().as_millis()
+}
+
 fn main() {
     let mut handles = vec![];
     for i in 0..10 {
-        handles.push(thread::spawn(move || {
-            let start = Instant::now();
-            thread::sleep(Duration::from_millis(250));
-            println!("thread {} is complete", i);
-            start.elapsed().as_millis()
-        }));
+        handles.push(thread::spawn(move || thread_func(i)));
     }
 
     let mut results: Vec<u128> = vec![];
     for handle in handles {
+        results.push(handle.join().unwrap());
         // TODO: a struct is returned from thread::spawn, can you use it?
     }
 

exercises/20_threads/threads2.rs

@@ -7,9 +7,7 @@
 // Execute `rustlings hint threads2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
 
@@ -19,7 +17,7 @@ struct JobStatus {
 
 fn main() {
     // TODO: `Arc` isn't enough if you want a **mutable** shared state
-    let status = Arc::new(JobStatus { jobs_completed: 0 });
+    let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
 
     let mut handles = vec![];
     for _ in 0..10 {
@@ -27,7 +25,8 @@ fn main() {
         let handle = thread::spawn(move || {
             thread::sleep(Duration::from_millis(250));
             // TODO: You must take an action before you update a shared value
-            status_shared.jobs_completed += 1;
+            let mut s = status_shared.lock().unwrap();
+            s.jobs_completed += 1;
         });
         handles.push(handle);
     }
@@ -38,5 +37,5 @@ fn main() {
     }
 
     // TODO: Print the value of `JobStatus.jobs_completed`
-    println!("Jobs completed: {}", ???);
+    println!("Jobs completed: {}", status.lock().unwrap().jobs_completed);
 }