src/doc/rust-by-example/src/hello.md

   1 # Hello World
   2
   3 This is the source code of the traditional Hello World program.
   4
   5 ```rust,editable
   6 // This is a comment, and is ignored by the compiler
   7 // You can test this code by clicking the "Run" button over there ->
   8 // or if you prefer to use your keyboard, you can use the "Ctrl + Enter" shortcut
   9
  10 // This code is editable, feel free to hack it!
  11 // You can always return to the original code by clicking the "Reset" button ->
  12
  13 // This is the main function
  14 fn main() {
  15     // Statements here are executed when the compiled binary is called
  16
  17     // Print text to the console
  18     println!("Hello World!");
  19 }
  20 ```
  21
  22 `println!` is a [*macro*][macros] that prints text to the
  23 console.
  24
  25 A binary can be generated using the Rust compiler: `rustc`.
  26
  27 ```bash
  28 $ rustc hello.rs
  29 ```
  30
  31 `rustc` will produce a `hello` binary that can be executed.
  32
  33 ```bash
  34 $ ./hello
  35 Hello World!
  36 ```
  37
  38 ### Activity
  39
  40 Click 'Run' above to see the expected output. Next, add a new
  41 line with a second `println!` macro so that the output
  42 shows:
  43
  44 ```text
  45 Hello World!
  46 I'm a Rustacean!
  47 ```
  48
  49 [macros]: macros.md