模块基础 #

mod front_of_house {
    pub mod hosting {
        pub fn add_to_waitlist() {
            println!("添加到等待列表");
        }
    }
}

fn main() {
    front_of_house::hosting::add_to_waitlist();
}

src/
├── main.rs
└── front_of_house/
    ├── mod.rs
    └── hosting.rs

// src/main.rs
mod front_of_house;

fn main() {
    front_of_house::hosting::add_to_waitlist();
}

// src/front_of_house/mod.rs
pub mod hosting;

// src/front_of_house/hosting.rs
pub fn add_to_waitlist() {
    println!("添加到等待列表");
}

mod back_of_house {
    pub struct Breakfast {
        pub toast: String,
        seasonal_fruit: String,
    }
    
    impl Breakfast {
        pub fn summer(toast: &str) -> Breakfast {
            Breakfast {
                toast: String::from(toast),
                seasonal_fruit: String::from("peaches"),
            }
        }
    }
}

fn main() {
    let mut meal = back_of_house::Breakfast::summer("Rye");
    meal.toast = String::from("Wheat");
    // meal.seasonal_fruit = String::from("blueberries");  // 错误：私有字段
}

mod front_of_house {
    pub mod hosting {
        pub fn add_to_waitlist() {}
    }
}

use front_of_house::hosting;

fn main() {
    hosting::add_to_waitlist();
}

use std::io::Result as IoResult;

use std::io::{self, Read, Write};
use std::collections::{HashMap, HashSet};

use std::collections::*;