How to share data between threads with Arc Mutex

Wrap your data in Arc for shared ownership and Mutex for safe mutation, then clone the Arc to pass it to each thread.

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

fn main() {
    let data = Arc::new(Mutex::new(vec![1, 2, 3]));
    let mut handles = vec![];

    for _ in 0..3 {
        let data_clone = Arc::clone(&data);
        let handle = thread::spawn(move || {
            let mut num = data_clone.lock().unwrap();
            num.push(4);
        });
        handles.push(handle);
    }

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

    println!("{:?}", *data.lock().unwrap());
}

Think of Arc as a shared ownership ticket that lets multiple threads hold the same data, and Mutex as a lock that ensures only one thread changes the data at a time. You use this combination when you need several threads to safely read and update the same variable simultaneously. It prevents crashes caused by two threads trying to write to the same memory location at once.