arc1.rs (1514B)
1 // In this exercise, we are given a `Vec` of `u32` called `numbers` with values 2 // ranging from 0 to 99. We would like to use this set of numbers within 8 3 // different threads simultaneously. Each thread is going to get the sum of 4 // every eighth value with an offset. 5 // 6 // The first thread (offset 0), will sum 0, 8, 16, … 7 // The second thread (offset 1), will sum 1, 9, 17, … 8 // The third thread (offset 2), will sum 2, 10, 18, … 9 // … 10 // The eighth thread (offset 7), will sum 7, 15, 23, … 11 // 12 // Each thread should own a reference-counting pointer to the vector of 13 // numbers. But `Rc` isn't thread-safe. Therefore, we need to use `Arc`. 14 // 15 // Don't get distracted by how threads are spawned and joined. We will practice 16 // that later in the exercises about threads. 17 18 // Don't change the lines below. 19 #![forbid(unused_imports)] 20 use std::{sync::Arc, thread}; 21 22 fn main() { 23 let numbers: Vec<_> = (0..100u32).collect(); 24 25 // TODO: Define `shared_numbers` by using `Arc`. 26 // let shared_numbers = ???; 27 28 let mut join_handles = Vec::new(); 29 30 for offset in 0..8 { 31 // TODO: Define `child_numbers` using `shared_numbers`. 32 // let child_numbers = ???; 33 34 let handle = thread::spawn(move || { 35 let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum(); 36 println!("Sum of offset {offset} is {sum}"); 37 }); 38 39 join_handles.push(handle); 40 } 41 42 for handle in join_handles.into_iter() { 43 handle.join().unwrap(); 44 } 45 }