use std::sync::Arc;
use std::sync::Mutex;
use std::ops::Deref;
use std::ops::DerefMut;

fn main1() {

    println!("Hello!");

    let n = 10;

    let arc = Arc::new(Mutex::new(Some(n)));

    let arc_clone = arc.clone();

    println!("lock1: req");
    let mut mutex_guard = arc_clone.lock().unwrap();
    println!("lock1: got");

    match mutex_guard.deref_mut() {
        Some(ref mut x) => {
            println!("Got {}", x);
            *x = 11;
        },
        None => panic!("Error."),
    };

    drop(mutex_guard);

    println!("lock2: req");
    let mut mutex_guard = arc_clone.lock().unwrap();
    println!("lock1: got");

    match mutex_guard.deref_mut() {
        Some(ref mut x) => {
            println!("Got {}", x);
            *x = 12;
        },
        None => panic!("Error."),
    };
}

fn main() {

    println!("Hello!");

    let n = 10;

    let arc = Arc::new(Mutex::new(Some(n)));

    let arc_clone = arc.clone();

    println!("lock1: req");
    let mut mutex_guard = arc_clone.lock().unwrap();
    println!("lock1: got");

    let opt = &mut *mutex_guard;
    match opt {
        Some(ref mut x) => {
            println!("Got {}", x);
            *x = 11;
        },
        None => panic!("Error."),
    };

    drop(opt);

    println!("lock2: req");
    let mut mutex_guard = arc_clone.lock().unwrap();
    println!("lock1: got");

    match mutex_guard.deref_mut() {
        Some(ref mut x) => {
            println!("Got {}", x);
            *x = 12;
        },
        None => panic!("Error."),
    };
}