Grouping related code in modules is a way to organize code within a crate for readability and easy reuse. Modules also allow us to control the privacy of items, because code within a module is private by default. For example, let's say we want to write a library crate that provides the functionality of a restaurant. We could organize our code into modules based on the different areas of the restaurant, such as front of house and back of house.
The front of house module would contain code related to interacting with customers, such as adding customers to the waitlist, seating them at tables, and taking their orders. The back of house module would contain code related to the kitchen, such as cooking food, cleaning dishes, and managing inventory. This would make our code easier to read and understand, and it would also make it easier to reuse our code in other projects. Here is an example of how we could define the front of house module in Rust:
mod front_of_house {
fn add_to_waitlist() {}
fn seat_at_table() {}
fn take_order() {}
}
This module defines three functions: add_to_waitlist(), seat_at_table(), and take_order(). These functions are all related to the front of house area of a restaurant, so it makes sense to group them together in a module.
