Rust by Example

1 Hello World

This is the source code of the traditional Hello World program.

// This is a comment, and will be ignored by the compiler
// You can test this code by clicking the "Run" button over there ->
// or if prefer to use your keyboard, you can use the "Ctrl + Enter" shortcut

// This code is editable, feel free to hack it!
// You can always return to the original code by clicking the "Reset" button ->

// This is the main function
fn main() {
    // The statements here will be executed when the compiled binary is called

    // Print text to the console
    println!("Hello World!");
}

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

A binary can be generated using the Rust compiler: rustc.

$ rustc hello.rs

rustc will produce a hello binary that can be executed.

$ ./hello
Hello World!

Activity

Click 'Run' above to see the expected output. Next, add a new line with a second println! macro so that the output shows:

Hello World!
I'm a Rustacean!