feat:exercises

Author: build

exercises/smart_pointers/arc1.rs

@@ -21,19 +21,60 @@
 //
 // 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 = Arc::new(numbers);
+    let mut joinhandles = Vec::new();
+
+    for offset in 0..8 {
+        let child_numbers =  Arc::clone(&shared_numbers);
+        joinhandles.push(thread::spawn(move || {
+            let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
+            println!("Sum of offset {} is {}", offset, sum);
+        }));
+    }
+    for handle in joinhandles.into_iter() {
+        handle.join().unwrap();
+    }
+}
+// arc1.rs
+//
+// In this exercise, we are given a Vec of u32 called "numbers" with values
+// ranging from 0 to 99 -- [ 0, 1, 2, ..., 98, 99 ] We would like to use this
+// set of numbers within 8 different threads simultaneously. Each thread is
+// going to get the sum of every eighth value, with an offset.
+//
+// The first thread (offset 0), will sum 0, 8, 16, ...
+// The second thread (offset 1), will sum 1, 9, 17, ...
+// The third thread (offset 2), will sum 2, 10, 18, ...
+// ...
+// The eighth thread (offset 7), will sum 7, 15, 23, ...
+//
+// Because we are using threads, our values need to be thread-safe.  Therefore,
+// we are using Arc.  We need to make a change in each of the two TODOs.
+//
+// Make this code compile by filling in a value for `shared_numbers` where the
+// first TODO comment is, and create an initial binding for `child_numbers`
+// where the second TODO comment is. Try not to create any copies of the
+// `numbers` Vec!
+//
+// Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
 #![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);
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
-        let child_numbers = // TODO
+        let child_numbers =  Arc::clone(&shared_numbers);
         joinhandles.push(thread::spawn(move || {
             let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);