use std::sync::{Arc, Mutex}; // Rc is not thread safe, but Arc is. (Atomic Reference Count)
use std::thread;

fn single_thread_example() {
    let m = Mutex::new(5);

    {
        let mut num = m.lock().unwrap();
        *num = 6;
    } // Reference to mutex value goes out of scope, lock is released

    println!("m = {:?}", m);
}

fn multi_thread_example() {
    let counter = Arc::new(Mutex::new(0));
    let mut handles = vec![];

    for _ in 0..10 {
        let counter = Arc::clone(&counter);
        let handle = thread::spawn(move || {
           let mut num = counter.lock().unwrap();

            *num += 1;
        });
        handles.push(handle);
    }

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

    println!("Result: {}", *counter.lock().unwrap());
}

fn main() {
    single_thread_example();

    multi_thread_example();
}