Threads overview in Rust - Mini Project: Build & Apply

Threads overview

📖 Scenario: You are building a simple Rust program that uses threads to run tasks at the same time. This is like having multiple friends working on different parts of a project together.

🎯 Goal: Create a Rust program that starts a new thread to print a message, while the main thread prints its own message. You will learn how to create and run threads and wait for them to finish.

📋 What You'll Learn

Create a variable called handle that starts a new thread using std::thread::spawn

Inside the new thread, print the message "Hello from the spawned thread!"

In the main thread, print the message "Hello from the main thread!"

Use handle.join().unwrap() to wait for the spawned thread to finish

💡 Why This Matters

🌍 Real World

Threads let programs do many things at once, like downloading files while showing a progress bar.

💼 Career

Understanding threads is important for building fast and responsive software in many jobs, including systems programming and web servers.

1

Create a new thread

Write a line of Rust code to create a variable called handle that starts a new thread using std::thread::spawn. Inside the thread, print the message "Hello from the spawned thread!".

Rust

# Create a variable called handle that starts a new thread
# Your code here

Hint

Use thread::spawn with a closure || { ... } to create the thread.

2

Print from the main thread

Add a line of Rust code to print the message "Hello from the main thread!" in the main thread after creating the handle variable.

Rust

use std::thread;

let handle = thread::spawn(|| {
    println!("Hello from the spawned thread!");
});

# Print "Hello from the main thread!" here
# Your code here

Hint

Use println!("Hello from the main thread!"); to print the message.

3

Wait for the spawned thread to finish

Add a line of Rust code to wait for the spawned thread to finish by calling handle.join().unwrap() after printing the main thread message.

Rust

use std::thread;

let handle = thread::spawn(|| {
    println!("Hello from the spawned thread!");
});

println!("Hello from the main thread!");

# Wait for the spawned thread to finish
# Your code here

Hint

Use handle.join().unwrap(); to wait for the thread to finish and handle any errors.

4

Run the program and see the output

Run the complete Rust program and print the output. The output should show messages from both the spawned thread and the main thread.

Rust

use std::thread;

fn main() {
    let handle = thread::spawn(|| {
        println!("Hello from the spawned thread!");
    });

    println!("Hello from the main thread!");

    handle.join().unwrap();

    # Run the program and observe the output
    # Your code here
}

Hint

The order of the messages may vary because threads run at the same time.