Introduction to Rust

Rust was born at Mozilla in 2010 with a clear goal: memory safety without a garbage collector. Today, Rust powers parts of Firefox, the Linux kernel, Cloudflare Workers, and tools like ripgrep. In this block you will explore what problems Rust solves that C and C++ leave open, and why companies like Microsoft, Google, and Amazon use Rust in safety-critical systems. You will understand the three design principles (safety, speed, concurrency) and assess when Rust is the right choice.

You set up your Rust workspace in the DevNinjas Dojo and get familiar with the toolchain: rustup for version management, cargo as the build system and package manager, rustc as the compiler. With cargo new you create your first project, build it with cargo build, and run it with cargo run. By the end of this block you know the project structure (Cargo.toml, src/main.rs) and have set up clippy and rustfmt as quality tools.

Rust is statically typed but supports type inference, so you do not need to annotate every type explicitly. You work with primitive types (i32, f64, bool, char), tuples, and arrays. Special focus goes to Rust's distinction between let (immutable) and let mut (mutable): immutability by default is a deliberate design decision. For control flow (if, loop, while, for), you will see that if is an expression and can return values directly.

Functions in Rust have explicit return types and return the last expression without return. You write functions with various parameters, use closures as anonymous functions, and organize code into modules with mod. Rust controls visibility through pub: private by default. Then you learn the difference between binary crates and library crates and pull in your first external dependency via Cargo.toml and crates.io.

Why does Rust have two string types? String and &str regularly confuse newcomers. In this block you clarify the difference between owned and borrowed data using strings, preparing you for the ownership concept on day 2. Then you work with Vec as a dynamic array and HashMap<K, V> for key-value pairs. Slices (&[T]) show you how Rust efficiently references parts of data structures without copying them.