Add progress reporting example

2. Atomics/progress-reporting-parking/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "progress-reporting-parking"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2. Atomics/progress-reporting-parking/src/main.rs

@@ -0,0 +1,45 @@
+use std::{
+    io::{self, Write},
+    sync::atomic::{AtomicUsize, Ordering::Relaxed},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let num_done = AtomicUsize::new(0);
+
+    let main_thread = thread::current();
+
+    let items = (0..100).collect::<Vec<_>>();
+
+    thread::scope(|s| {
+        s.spawn(|| {
+            items.iter().enumerate().for_each(|(i, &item)| {
+                process_item(item);
+                num_done.store(i + 1, Relaxed);
+                main_thread.unpark(); // Wake up the main thread
+            })
+        });
+
+        loop {
+            let n = num_done.load(Relaxed);
+            print_progress(n);
+            if n == 100 {
+                break; // All done
+            }
+            thread::park_timeout(Duration::from_secs(1));
+        }
+    });
+}
+
+fn print_progress(percentage: usize) {
+    match percentage {
+        p if p >= 100 => println!("\nDone!"),
+        _ => print!("\rWorking.. {percentage}/100"),
+    }
+    io::stdout().flush().unwrap();
+}
+
+fn process_item(_item: i32) {
+    thread::sleep(Duration::from_millis(100));
+}

Cargo.toml

@@ -2,4 +2,4 @@
 
 resolver = "2"
 
-members = [ "1. Basics of Rust Concurrency/lifetime-mutexguard","1. Basics of Rust Concurrency/scoped-threads", "2. Atomics/stop-flag"]
+members = [ "1. Basics of Rust Concurrency/lifetime-mutexguard","1. Basics of Rust Concurrency/scoped-threads", "2. Atomics/progress-reporting-parking", "2. Atomics/stop-flag"]