The Rust Programming Handbook

3

Functions in Rust

Welcome to Chapter 3! Now that we’ve covered Rust’s basic data types, let’s explore how to make them do things. In this chapter, we’ll focus on functions, the primary way to organize code and behavior in Rust. Think of them as the named recipes of your program: they bundle up logic into reusable blocks that you can call whenever you need them, which is fundamental to writing clean and maintainable software. By breaking down a complex problem into smaller, named pieces, your code becomes much easier to read, debug, and update.

While the basic idea of a function might be familiar if you’ve worked with other languages, its behavior in Rust is deeply connected to its most unique feature: the ownership system. A very important ...