03-rust-basics

Rust Hello World Tutorial

This tutorial provides a basic introduction to Rust programming language. We'll cover essential concepts and basic syntax.

Project Setup

1. Create a new Rust project:

cargo new rust-hello-world
cd rust-hello-world

2. Common Cargo Commands:

• cargo check: Check code for errors without building
• cargo build: Compile the project
• cargo run: Build and run the project
• cargo test: Run tests
• cargo doc: Generate documentation

Basic Concepts

Variables and Mutability

• By default, variables are immutable in Rust
• Use mut keyword to make variables mutable:

let x = 5; // immutable
let mut y = 5; // mutable

Common Data Types

1. Integer Types

   • Default is i32 (32-bit)
   • Signed: i8, i16, i32, i64, i128
   • Unsigned: u8, u16, u32, u64, u128

2. Floating-Point Types

   • Default is f64 (64-bit)
   • Types: f32, f64

3. Boolean Type

   • Values: true, false
   • Size: 1 byte

4. Character Type

   • Unicode scalar value
   • 4 bytes (32-bit)
   • Supports emoji and international characters

5. Compound Types

   • Tuples: Fixed-length collection of values of different types

   let tup: (i32, f64, bool) = (500, 6.4, true);

   • Arrays: Fixed-length collection of same type

   let arr: [i32; 5] = [1, 2, 3, 4, 5];

Functions

fn function_name(parameter: Type) -> ReturnType {
    // function body
}

Ownership

One of Rust's most unique features:

• Each value has a single owner
• Only one owner at a time
• Value is dropped when owner goes out of scope
• Prevents memory leaks and ensures memory safety

Example:

let s1 = String::from("hello");
let s2 = s1; // s1 is moved to s2, s1 is no longer valid

For simple types (integers, booleans, etc.), Rust automatically makes copies instead of moving ownership. These types implement the Copy trait.

Structs and Enums

Structs: Custom data types to group related data

struct User {
    username: String,
    email: String,
    active: bool,
}

Enums: Type that can be one of several variants

enum IpAddrKind {
    V4,
    V6,
}

Learning Resources

• The Rust Programming Language Book
• Rust by Example
• Tour of Rust
• Rust Playground

Next Steps

• Error handling with Result and Option
• Pattern matching with match expressions
• Collections (Vec, HashMap)
• Modules and packages
• Traits and generics