//类语法
class Dog {
  constructor(name ,age) {
   this.name = name
   this.age = age
  }
  
  eat() {
    console.log('肉骨头真好吃')
  }
}

//构造函数
function Dog(name, age) {
  this.name = name
  this.age = age
}
Dog.prototype.eat = function() {
  console.log('肉骨头真好吃')
}