Environment & Hello World

Setting Up Rust

1. Install via rustup

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

On Windows, download and run rustup-init.exe from https://rustup.rs.

After installation:

rustc --version   # rustc 1.78.0 (9b00956e5 2024-04-29)
cargo --version   # cargo 1.78.0 (54d8815d0 2024-03-26)

2. VS Code Setup

Install the rust-analyzer extension (extension id: rust-lang.rust-analyzer). This is the official extension — do not install the old "Rust" extension.

rust-analyzer provides:

• Real-time type inference
• Inline diagnostics from the borrow checker
• Code actions and refactors
• Go-to-definition across crates

3. Create a Project

cargo new hello_rust
cd hello_rust

This creates:

hello_rust/
  Cargo.toml
  src/
    main.rs

4. Your First Program

src/main.rs already contains Hello World:

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

Run it:

cargo run
# Compiling hello_rust v0.1.0
# Finished dev profile
# Running target/debug/hello_rust
# Hello, World!

Build a release binary (optimized):

cargo build --release
./target/release/hello_rust

5. println! is a Macro

The ! suffix means println! is a macro, not a function. Rust macros operate at compile time and can be variadic — that is why println!("{} {}", a, b) works without generic function overloads.

6. Cargo.toml

[package]
name    = "hello_rust"
version = "0.1.0"
edition = "2021"

[dependencies]

The edition field picks which Rust edition to use. Always use 2021 for new projects.

7. Useful Cargo Commands

cargo check      # fast type-check without producing a binary
cargo clippy     # linter — much stricter than the compiler
cargo fmt        # auto-format all Rust files
cargo test       # run all tests
cargo doc --open # build and open docs