Rust Cheat Sheet

Rust ownership, borrowing, pattern matching, error handling with Result, and core syntax for memory-safe systems code.

2 PagesAdvancedApr 2, 2026

Basic Syntax

Variables, control flow, and printing.

rust

fn main() {    let age = 30;                 // immutable by default    let mut count = 0;            // mutable    let name = "Ada";    let pi: f64 = 3.14159;    if age >= 18 {        println!("{} is an adult", name);    }    for i in 0..5 {        println!("Count: {}", i);    }}

Ownership & Borrowing

Rust's compile-time memory safety model.

rust

fn main() {    let s1 = String::from("hello");    let s2 = s1;              // s1 moved into s2, s1 no longer valid    // println!("{}", s1);    // compile error: value moved    let s3 = String::from("world");    let len = calculate_length(&s3);   // borrow, not move    println!("{} has length {}", s3, len);}fn calculate_length(s: &String) -> usize {    s.len()}

Error Handling

Result, Option, and the ? operator.

rust

use std::fs::File;fn read_file(path: &str) -> Result<String, std::io::Error> {    let contents = std::fs::read_to_string(path)?;  // ? propagates errors    Ok(contents)}fn main() {    match read_file("data.txt") {        Ok(text) => println!("{}", text),        Err(e) => println!("Error: {}", e),    }}