diff --git a/thread/src/main.rs b/thread/src/main.rs
index 90609d8..d7249f3 100644
--- a/thread/src/main.rs
+++ b/thread/src/main.rs
@@ -1,14 +1,19 @@
-use std::{ thread, time::Duration, };
+use std::{
+    thread,
+    sync::{ Arc, Mutex, },
+    time::Duration,
+};
 
-// sleep sort
-fn main() {
-    let in_vec = vec![2, 1, 5, 10, 7];
+fn sleep_sort(in_vec: Vec<u8>) -> Vec<u8> {
+    let out_vec = Arc::new(Mutex::new(vec![]));
 
     let mut all_threads = vec![];
     for i in in_vec {
+        let o_vec = out_vec.clone();
         let child = thread::spawn(move || {
-            thread::sleep(Duration::from_millis(i));
-            println!(">> {}", i);
+            thread::sleep(Duration::from_millis(i as u64));
+            let mut v = o_vec.lock().unwrap();
+            v.push(i);
         });
         all_threads.push(child);
     }
@@ -16,5 +21,18 @@ fn main() {
         t.join().ok();
     }
 
+    let v = out_vec.lock().unwrap();
+    v.to_vec()
+}
+
+// sleep sort
+fn main() {
+    let in_vec = vec![2, 1, 5, 10, 7];
+    let out_vec = sleep_sort(in_vec);
+
+    out_vec.iter().for_each(|i| println!("{}", i));
+
     println!("Finished!");
 }
+
+