Rust

Hello World & Ownership Example

// Hello World
fn main() {
    println!("Hello, World!");
}

// Basic Struct and Implementation
struct Person {
    name: String,
    age: u32,
}

impl Person {
    fn new(name: String, age: u32) -> Person {
        Person { name, age }
    }
    
    fn introduce(&self) {
        println!("Hi, I'm {} and I'm {} years old.", self.name, self.age);
    }
}

fn main() {
    let person = Person::new("Alice".to_string(), 25);
    person.introduce();
}

// Ownership and Error Handling
use std::fs::File;
use std::io::Read;

fn read_file_contents(filename: &str) -> Result<String, std::io::Error> {
    let mut file = File::open(filename)?;
    let mut contents = String::new();
    file.read_to_string(&mut contents)?;
    Ok(contents)
}

fn main() {
    match read_file_contents("example.txt") {
        Ok(contents) => println!("File contents: {}", contents),
        Err(error) => println!("Error reading file: {}", error),
    }
}

// Pattern Matching with Enums
enum Message {
    Quit,
    Move { x: i32, y: i32 },
    Write(String),
    ChangeColor(i32, i32, i32),
}

fn process_message(msg: Message) {
    match msg {
        Message::Quit => println!("Quit message received"),
        Message::Move { x, y } => println!("Move to coordinates: ({}, {})", x, y),
        Message::Write(text) => println!("Text message: {}", text),
        Message::ChangeColor(r, g, b) => println!("Change color to RGB({}, {}, {})", r, g, b),
    }
}