var Dog = function(name, breed, age, happiness, hunger, energy) {
  this.name = name;
  this.breed = breed;
  this.age = age;
  this.happiness = happiness;
  this.hunger = hunger;
  this.energy = energy;
};

Dog.prototype.feed = function(food){
    if(this.hunger - food > 0) {
      this.hunger -= food;
    } else {
      this.hunger = 0;
    }
  };

Dog.prototype.play = function(time) {
    if(this.happiness + time < 100) {
      this.happiness += time;
    } else {
      this.happiness = 100;
    }
    if(this.energy - time > 0) {
      this.energy -= time;
    } else {
      this.energy = 0;
    }
  };

Dog.prototype.nap = function(time) {
    if(this.energy + time < 100) {
      this.energy += time;
    } else {
      this.energy = 100;
    }
  }

var joey = new Dog('Joey', "Boxer", 10, 95, 10, 70);
console.log(joey.hunger);
joey.feed(2);
console.log(joey.hunger)