Hello, Rustacean!

👋 Hello, World!

Now that Rust is installed... Let's write your first program!

Open the main.rs file inside your project folder (hello_rust/src/main.rs), and you'll see this:

fn main() {
    println!("Hello, world!");
}

Let's break it down...

🧱 Anatomy of a Rust Program

fn main() {
    println!("Hello, world!");
}

• 🔹 fn means function
• 🔹 main() is where the program starts
• 🔹 { ... } is a code block
• 🔹 println! prints a message to the terminal
• 🔹 "Hello, world!" is a string
• 🔹 ! means it's a macro
• 🔹 Every line ends with a semicolon ;

🖨️ What is println!?

println! is a macro that prints text to the screen.

#![allow(unused)]
fn main() {
println!("Hello, Rustacean!");
}

You can print anything inside the quotes!

Example:

#![allow(unused)]
fn main() {
println!("My favorite number is {}", 42);
}

The {} gets replaced with the value. It's like a mini magic placeholder!

💬 Add Some Comments

Comments are notes for humans. Rust ignores them.

You write them like this:

#![allow(unused)]
fn main() {
// This is a single-line comment

/*
This is a
multi-line comment
*/
}

Comments help you explain what your code does!

✨ Challenge Time!

Try changing your code:

• ✅ Print your name
• ✅ Print your age
• ✅ Print something in your own language
• ✅ Add a comment that explains what you did

✅ Summary

• You wrote your first Rust program!
• Learned about fn, main, and println!
• Understood how macros and strings work
• Learned how to write comments