rustp-3.trait

//1.trait定义与其他类型共享的功能，类似其他语言的接口
//（1）可以通过trait以抽象的方式定义共享的行为
// (2) 可以使用trait bounds指定泛型是任何拥有特定行为的类型
//2. 定义trait
//3. 实现trait
//4. 默认实现: 可以在定义trait的时候提供默认的行为,trait的类型可以使用默认的行为.
//5. trait作为参数

//2.
pub trait GetInformation {
    fn get_name(&self) -> &String;
    fn get_age(&self) -> u32;
  }
trait SchoolName {
    fn get_school_name(&self) -> String {//默认实现
        String::from("HongXing School")//避免悬垂引用
      }
  }
//3.
pub struct Student {
    pub name: String,
    pub age: u32,
  }

impl SchoolName for Student {
     
  }
impl GetInformation for Student {
    fn get_name (&self) -> &String {
        &self.name
      }
    fn get_age(&self) -> u32 {//这里因为u32实现了copy trait类型，所以返回本体
        self.age
      }
  }
pub struct Teacher {
    pub name:String,
    pub age: u32,
    pub subject: String,
  }
impl GetInformation for Teacher {
    fn get_name (&self) -> &String {
        &self.name
      }
    fn get_age(&self) -> u32 {//这里因为u32实现了copy trait类型，所以返回本体
        self.age
      }
  }
impl SchoolName for Teacher {
    fn get_school_name(&self) -> String {
        String::from("Guangmingschool")//修改默认实现
      } 
  }
//4.
//5.
fn print_information(item: impl GetInformation) {
  //这里只关心是否实现impl trait，然后调用item实现的方法即可
  println!("name = {}",item.get_name());
  println!("age = {}",item.get_age());

  }
fn main() {
   let s = Student{name:"xiaoming".to_string(),age:10};
   let t = Teacher{name:"xiaohu".to_string(),age:30,subject: "math".to_string};
   println!("student, name = {},age = {}",s.get_name(),s.get_age());
   println!("student, name = {},age = {}",t.get_name(),t.get_age());
   
   let s_school_name = s.get_school_name();
   println!("student school name = {}",s_school_name);
   let t_school_name = t.get_school_name();
   print_information(s);
   print_information(t);
  }