Rust Comments

Commenting in Rust is similar to other languages (C, Java) and supports two types of comments:

Example

// This is the first type of comment

/* This is the second type of comment */

/*
 * Multi-line comment
 * Multi-line comment
 * Multi-line comment
 */

Comments for Documentation

In Rust, using // makes everything after it until the first newline a comment.

Under this rule, three forward slashes /// are still valid as the start of a comment. Therefore, Rust uses /// as the beginning of documentation comments:

Example

/// Adds one to the number given.
///
/// # Examples
///
///

/// let x = add(1, 2); /// /// ```

fn add(a: i32, b: i32) -> i32 { return a + b; }

fn main() { println!("{}", add(2, 3)); } ```

The function add in the program will have an elegant comment and can be displayed in the IDE:

Tip: Cargo has a cargo doc feature that allows developers to convert documentation comments in the project into HTML documentation.