threads1 solution

exercises/20_threads/threads1.rs

@@ -3,31 +3,35 @@
 // wait until all the spawned threads have finished and should collect their
 // return values into a vector.
 
-use std::thread;
-use std::time::{Duration, Instant};
+use std::{
+    thread,
+    time::{Duration, Instant},
+};
 
 fn main() {
-    let mut handles = vec![];
+    let mut handles = Vec::new();
     for i in 0..10 {
-        handles.push(thread::spawn(move || {
+        let handle = thread::spawn(move || {
             let start = Instant::now();
             thread::sleep(Duration::from_millis(250));
-            println!("thread {} is complete", i);
+            println!("Thread {i} done");
             start.elapsed().as_millis()
-        }));
+        });
+        handles.push(handle);
     }
 
-    let mut results: Vec<u128> = vec![];
+    let mut results = Vec::new();
     for handle in handles {
-        // TODO: a struct is returned from thread::spawn, can you use it?
+        // TODO: Collect the results of all threads into the `results` vector.
+        // Use the `JoinHandle` struct which is returned by `thread::spawn`.
     }
 
     if results.len() != 10 {
-        panic!("Oh no! All the spawned threads did not finish!");
+        panic!("Oh no! Some thread isn't done yet!");
     }
 
     println!();
     for (i, result) in results.into_iter().enumerate() {
-        println!("thread {} took {}ms", i, result);
+        println!("Thread {i} took {result}ms");
     }
 }