How do you define structs and impl blocks in Rust?

A struct groups related data under a named type: struct Point { x: f64, y: f64 }. You instantiate it with Point { x: 1.0, y: 2.0 }. An impl block adds methods and associated functions to a struct. Methods take &self (immutable access), &mut self (mutable access), or self (takes ownership). Associated functions (like static methods) do not take a self parameter — Point::new() is a common convention for constructors. Multiple impl blocks are allowed for the same type. Structs plus impl blocks are how Rust achieves object-oriented encapsulation without classes or inheritance.