In the previous tutorial, we learned lifetimes. Now we learn two features that make Rust code clean and expressive: closures and iterators. Closures are anonymous functions you can store in variables and pass to other functions. Iterators let you process collections step by step. Together, they replace most loops with short, readable code. What Is a Closure? A closure is a function without a name. It can capture variables from its environment: ...
In the previous tutorial, we learned generics. Now we learn lifetimes — the last piece of Rust’s ownership system. Lifetimes answer one question: “How long does this reference live?” The Rust compiler uses lifetimes to make sure every reference is always valid. No dangling pointers. No use-after-free bugs. No segfaults. If you have struggled with lifetime errors, this tutorial will help. Most of the time, lifetimes are invisible — the compiler figures them out for you. But sometimes you need to tell the compiler what you mean. ...
In the previous tutorial, we learned traits — how to define shared behavior. Now we learn generics — how to write code that works with many types without repeating yourself. You already use generics every day in Rust. Vec<T>, Option<T>, Result<T, E> — these are all generic types. The T is a placeholder for any type. In this tutorial, you learn to write your own. Why Generics? Without generics, you would write separate functions for each type: ...
In the previous tutorial, we learned error handling with Result and Option. Now we learn traits — Rust’s way to define shared behavior between types. If you know interfaces in Java, Kotlin, or TypeScript, traits are similar. A trait says “any type that implements me must have these methods.” But Rust traits go further — they support default methods, operator overloading, and dynamic dispatch. What Is a Trait? A trait defines a set of methods that a type must implement. Think of it as a contract. Any type that signs the contract must provide the required methods. ...