9.10 Visibility and Modules

Rust carefully manages visibility. By default, structs and fields are private to the module in which they’re defined. Making them accessible outside their module requires using the pub keyword.

9.10.1 Visibility with pub

pub struct PublicStruct {
    pub field: Type,
    private_field: Type,
}
  • PublicStruct is visible outside its defining module.
  • field is publicly accessible, but private_field remains private.

9.10.2 Modules and Struct Visibility

By default, structs and fields are private within their module, meaning they cannot be accessed externally. This design promotes well-defined APIs and prevents external code from relying on internal implementation details. You will learn more about modules and crates later in this book.