Rust：结构体

墨蓝 2022-04-01 03:58 201阅读 0赞

### 文章目录 ###

*  普通结构体
 *   *  定义普通结构体以及结构体实例化
     *  使用结构体作为返回值
 *  元组结构体

# 普通结构体 #

## 定义普通结构体以及结构体实例化 ##

fn main(){
        struct User{
        username:String,    //字段
        email:String,
        sign_in_count:u64,
        active:bool,
        }
    
        let  user1 = User{
            email:String::from("someone@example.com"),
            username:String::from("username123"),
            active:true,
            sign_in_count:1,
        };
    
        println!("{}, {}, {}, {}", user1.email, user1.username, user1.active, user1.sign_in_count);
    
        //整个实例必须是可变的；Rust 并不允许只将某个字段标记为可变
         let mut user2 = User{
            email:String::from("someone@example.com"),
            username:String::from("username123"),
            active:user1.active,
            sign_in_count:user1.sign_in_count,
        };
    
        user2.username = String::from("xixibiya");
    
        println!("{}, {}, {}, {}", user2.email, user2.username, user2.active, user2.sign_in_count);
    
        let  user3 = User{
            email:String::from("someone@example.com"),
            username:String::from("username123"),
            ..user1   //为一个 User 实例设置新的 email 和 username 值，不过其余值来自 user1 变量中实例的字段
        };
    
        println!("{}, {}, {}, {}", user3.email, user3.username, user3.active, user3.sign_in_count);
    }

## 使用结构体作为返回值 ##

struct User{
        username:String,
        email:String,
        sign_in_count:u64,
        active:bool,
    }
    
    fn main(){
        let user1 = build_user(String::from("someone@example.com"), String::from("username123"));
        println!("{}, {}, {}, {}", user1.email, user1.username, user1.active, user1.sign_in_count);
    
        let user2 = build_user_two(String::from("someone@example.com"), String::from("username123"));
        println!("{}, {}, {}, {}", user2.email, user2.username, user2.active, user2.sign_in_count);
    }
    
    fn build_user(email:String, username:String)->User{
        return User{
            email:email,
            username:username,
            active:true,
            sign_in_count:1,
        };
    }
    
    //参数名与字段名都完全相同,可以使用 字段初始化简写语法
    fn build_user_two(email:String, username:String)->User{
        return User{
            email,
            username,
            active:true,
            sign_in_count:1,
        };
    }

# 元组结构体 #

> 没有具体的字段名，只有字段的类型

fn main(){
        struct Color(i32, i32, i32);
        struct Point(i32, i32, i32);
    
        let black = Color(0, 0, 0);
        let white = Color(1, 1, 1);
        println!("{}, {}", black.0, white.0);
    
        let point1 = Point(0, 0, 0);
        let point2 = Point(1, 1, 1);
        println!("{}, {}", point1.0, point2.0);
    }

参考：https://kaisery.github.io/trpl-zh-cn/ch05-01-defining-structs.html?search=