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# Hello World

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

    // This is a comment, and is ignored by the compiler.
    // You can test this code by clicking the "Run" button over there ->
    // or if you 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() {
        // Statements here are 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!