rust入门（4） Trait 特征

//类型 c#中的接口 interface

//      1抽象的方式定义共享的行为

//      2trait bounds 指定泛型是任何拥有特定行为的类型

//定义两个结构体

pub struct  Student{

    pub name:String,

    pub age:u32,

}

pub struct Teacher{

    pub name :String,

    pub age:u32,

    pub subject:String,

}

 

 

//定义trait

pub trait GetInfomation{

    fn get_name(&self)->&String;

    fn get_age(&self)->u32;

}

pub trait GetName{

    fn get_name(&self)->&String;

}

pub trait GetAge{

    fn get_age(&self)->i32;

}

pub trait SchoolName{

　　get_school_name(&self)->String

　　{　String::from("红心学校")　}

}

//实现trait

impl GetInfomation for Student{

    fn get_name(&self)->&String{

        &self.name

    }

    fn get_age(&self)->u32{

        self.age

    }

}

 

impl GetName for Student{

    fn get_name(&self)->&String {

        &&self.name

    }

}

impl GetAge for Student{

    fn get_age(&self)->i32 {

        self.age

    }

}

impl GetInfomation for Teacher{

    fn get_name(&self)->&String{

        &self.name

    }

    fn get_age(&self)->u32{

        self.age

    }

}

//默认实现 学生的是默认实现，老师的在 impl 中重写下

impl SchoolName for Student{}

impl SchoolName for Teacher{

    fn get_school_name(&self)->String{

        String::from("兰心小学")

    }

}

 

//trait 作为参数

fn pint_infomation(item:&impl GetInfomation)

{

　　pintln!("name is {},age is {}",item.get_name(),item.get_age());

}

Trait Bound 语法   就是用trait 作为参数的另一种写法 跟之前的泛型有联系了

fn print_infomation_with_trait_bound<T:GetInfomation>(item:&T){

    println!("name is {}",item.get_name());

    println!("age is {}",item.get_age());

}

fn print_infomation_with_muilty_trait<T>(item:&T)

where T:GetAge+GetName

{

    println!("name is {}",item.get_name());

    println!("age is {}",item.get_age());

}

//trait 作为返回值

fn produce_item_with_age()->impl GetAge{

    Student{name:"小强".to_string(),age:19}

}

fn main() {

     let s = Student{name:String::from("张三"),age:1};

     let t=Teacher{name:String::from("王老师"),age:18,subject:String::from("数学")};

     println!("student name={},age={}",s.get_name(),s.get_age());

     println!("teacher name={},age={}",t.get_name(),t.get_age());

　　let student_school_name = s.get_school_name();

       let teacher_school_name = t.get_school_name();

 let s=produce_item_with_age();

}