「Rustを30分で紹介する(訳)」のコードを1.9.0で書いてみるとこんな感じ？

README.md

Rustを30分で紹介する(訳) - uehaj's blogのコードをRust 1.9.0で書いてみました。

よくわからない😇

concurrency_01.rs

use std::thread;
use std::sync::mpsc;

fn main() {
    let numbers = [1, 2, 3];

    let (tx, rx) = mpsc::channel();
    tx.send(numbers).unwrap();

    let handle = thread::spawn(move || {
        let numbers = rx.recv().unwrap();
        println!("{}", numbers[0]);
    });

    handle.join().unwrap();
}

concurrency_02.rs

use std::thread;
use std::sync::mpsc;
use std::sync::Arc;

fn main() {
    let numbers = [1, 2, 3];

    let numbers_arc = Arc::new(numbers);

    let handles: Vec<_> = (0..numbers.len()).into_iter().map(|num| {
        let (tx, rx) = mpsc::channel();
        tx.send(numbers_arc.clone()).unwrap();

        thread::spawn(move || {
            let local_arc = rx.recv().unwrap();
            println!("{}", (*local_arc)[num]);
        })
    }).collect();

    for h in handles {
        h.join().unwrap();
    }
}

concurrency_03.rs

use std::thread;
use std::sync::mpsc;
use std::sync::{Arc, Mutex};

fn main() {
    let numbers = [1, 2, 3];

    let numbers_arc = Arc::new(Mutex::new(numbers));

    let handles: Vec<_> = (0..numbers.len()).into_iter().map(|num| {
        let (tx, rx) = mpsc::channel();
        tx.send(numbers_arc.clone()).unwrap();

        thread::spawn(move || {
            let local_arc = rx.recv().unwrap();
            let mut task_numbers = local_arc.lock().unwrap();
            (*task_numbers)[num] += 1;
            println!("{}", (*task_numbers)[num]);
            // println!("{:?}", *task_numbers);
        })
    }).collect();

    for h in handles {
        h.join().unwrap();
    }
}

ownership_01.rs

fn dangling() -> &i32 {
    let i = 1234;
    return &i;
}

fn add_one() -> i32 {
    let num = dangling();
    return *num + 1;
}

fn main() {
    let num = add_one();
    println!("{}", num);
}

ownership_02.rs

fn dangling() -> Box<i32> {
    let x = Box::new(1234);
    return x;
}

fn add_one() -> i32 {
    let num = dangling();
    return *num + 1;
}

fn main() {
    let num = add_one();
    println!("{}", num);
}