mirror of
https://github.com/notohh/rustlings.git
synced 2024-12-18 06:58:10 -05:00
45 lines
1.5 KiB
Rust
45 lines
1.5 KiB
Rust
// In this exercise, we are given a `Vec` of `u32` called `numbers` with values
|
|
// ranging from 0 to 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, …
|
|
//
|
|
// Each thread should own a reference-counting pointer to the vector of
|
|
// numbers. But `Rc` isn't thread-safe. Therefore, we need to use `Arc`.
|
|
//
|
|
// Don't get distracted by how threads are spawned and joined. We will practice
|
|
// that later in the exercises about threads.
|
|
|
|
// Don't change the lines below.
|
|
#![forbid(unused_imports)]
|
|
use std::{sync::Arc, thread};
|
|
|
|
fn main() {
|
|
let numbers: Vec<_> = (0..100u32).collect();
|
|
|
|
let shared_numbers = Arc::new(numbers);
|
|
// ^^^^^^^^^^^^^^^^^
|
|
|
|
let mut join_handles = Vec::new();
|
|
|
|
for offset in 0..8 {
|
|
let child_numbers = Arc::clone(&shared_numbers);
|
|
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
let handle = thread::spawn(move || {
|
|
let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
|
|
println!("Sum of offset {offset} is {sum}");
|
|
});
|
|
|
|
join_handles.push(handle);
|
|
}
|
|
|
|
for handle in join_handles.into_iter() {
|
|
handle.join().unwrap();
|
|
}
|
|
}
|