Rust中struct的function与method

//类似java里的pojo类
struct Pet{
    name:String,
    age:i8, //最后1个,不能省略
}

impl Pet{
    //定义函数(类似java里的static方法)
    fn to_string(pet:&Pet)->String{
        format!("name:{},age:{}",pet.name,pet.age)
    }

    //定义方法(类似java里的实例方法)
    fn to_str(&self)->String{
        format!("name:{},age:{}",self.name,self.age) 
    }
}

fn main() {
    let dog = Pet{
        name:String::from("dog"),
        age:1
    };
    //调用Pet里的function
    println!("{}",Pet::to_string(&dog));
    //调用Pet实例dog上的method
    println!("{}",dog.to_str());
}