Hello, World!
fn main() {
println!("Hello, World!");
}1 file
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Rust 1.98.1Readymain.rsLn 1, Col 1Spaces: 4UTF-8
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Rust is a statically typed systems programming language that originated as a Mozilla project led by Graydon Hoare, reaching its stable 1.0 release in 2015. Its defining feature is the ownership and borrowing model, which guarantees memory safety and data-race freedom at compile time without a garbage collector. Rust is multi-paradigm, blending imperative, functional, and zero-cost abstractions.
Today Rust is popular for performance-critical and safety-sensitive software, including operating system components, web assembly, networking, and command-line tools, and has been adopted in the Linux kernel. Its package manager Cargo and the crates.io registry make dependency management straightforward. This compiler runs Rust 1.68.2, so you can use the ownership system, traits, pattern matching, and the standard library in your programs.
main.rs is the entry point. Add helper files from the explorer and import them into your project.
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main.rs declares the sibling helper.rs module with mod.
mod helper;
fn main() {
println!("{}", helper::answer());
}
pub fn answer() -> i32 {
42
}
fn main() {
println!("Hello, World!");
}use std::io;
fn main() {
let mut name = String::new();
io::stdin().read_line(&mut name).unwrap();
println!("Hello, {}!", name.trim());
}fn main() {
let fruits = vec!["apple", "banana", "cherry"];
for (i, fruit) in fruits.iter().enumerate() {
println!("{} {}", i + 1, fruit);
}
}fn factorial(n: u64) -> u64 {
if n <= 1 { 1 } else { n * factorial(n - 1) }
}
fn main() {
println!("{}", factorial(5));
}fn parse(s: &str) -> Result<i32, std::num::ParseIntError> {
s.parse::<i32>()
}
fn main() {
match parse("abc") {
Ok(n) => println!("Got {}", n),
Err(e) => println!("Error: {}", e),
}
}use std::collections::HashMap;
fn main() {
let mut counts: HashMap<char, i32> = HashMap::new();
for c in "banana".chars() {
*counts.entry(c).or_insert(0) += 1;
}
for (ch, n) in &counts {
println!("{}: {}", ch, n);
}
}fn main() {
let mut nums = vec![3, 1, 4, 1, 5];
nums.sort();
let doubled: Vec<i32> = nums.iter().map(|x| x * 2).collect();
println!("{:?}", doubled);
}struct Person {
name: String,
age: u32,
}
impl Person {
fn describe(&self) -> String {
format!("{} ({})", self.name, self.age)
}
}
fn main() {
let p = Person { name: String::from("Ada"), age: 36 };
println!("{}", p.describe());
}enum Shape {
Circle(f64),
Square(f64),
}
fn area(s: &Shape) -> f64 {
match s {
Shape::Circle(r) => 3.14159 * r * r,
Shape::Square(side) => side * side,
}
}
fn main() {
println!("{}", area(&Shape::Square(3.0)));
}trait Greet {
fn hello(&self) -> String;
}
struct Dog;
impl Greet for Dog {
fn hello(&self) -> String {
String::from("Woof")
}
}
fn main() {
let d = Dog;
println!("{}", d.hello());
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Rust is one of 25 linked-project compilers. Run always starts main.rs; selecting a helper tab changes what you edit, not the entry file.
main.rs declares the sibling helper.rs module with mod.
Linked-project languages (25): Node.js, TypeScript, Deno, Python, C, Go, Dart, Swift, Rust, Ruby, PHP, Java, Kotlin, C++, C#, Nim, Crystal, Haxe, Zig, Scala, D, Verilog, GDScript, Bun, Objective-C.
Single-file scratchpads (46): Matplotlib, NumPy, pandas, Haskell, Clojure, Perl, Lua, Tcl, jq, Raku, Elixir, Bash, Zsh, Nushell, R, Assembly (NASM), Julia, Octave, Groovy, PowerShell, Visual Basic .NET, Odin, Pascal, Lisp, Erlang, CoffeeScript, COBOL, BASIC, V, Racket, OCaml, Prolog, AWK, Emacs Lisp, Emojicode, Forth, F#, Fortran, Assembly (NASM64), Solidity, Mojo, Ada, WASM (WAT), Gleam, Shell Script (sh), Scheme. Their extra project files are not submitted to the runtime.
Download project exports every Rust tab and a README in one ZIP archive.