struct

5 Struct

结构体是一个自定义的数据类型，允许你把一些相关的数据组合打包到一起，组成一个有意义的组。

define

struct User {
	username: String,
	email: String,
	sign_in_count: u64,
	active: bool,
}

instance

let user1 = User{
	username: String::from("wutb"),
	email: String::from("wutb@asiainfo.com")
	sign_in_count: 1,
	active: true,
}

create from other instance

let user2 = User{
	username: String::from("lixu"),
	email: String::from("lixu@qq.com"),
	..user1
}

Tuple Struct without named fields

struct Color(i32, i32, i32);

method syntax

method(方法)，与function(函数)非常相似，不同之处：

1. 必须在struct的上下文中声明
2. 第一个参数必须是self

   #[derive(Debug)] // annotation
   struct Rectangle {
       width: u32,
       height: u32,
   }
   impl Rectangle {
       fn area(&self) -> u32 {
           self.width * self.height
       }
   }

associated function 关联函数

functions within impl blocks that don’t take self as a parameter.
调用关联函数时使用::标识符，例如， String::from()

Multiple impl Blocks

struct is allowed to have multiple impl blocks