Animals Part 1. OOP basics

Story points 3
Tags oop
Hard Prerequisites
  • PROJECTS: Person

    • This Challenge should test topics from your OOP knowledge

    1. Encapsulation
    2. Inheritance
    3. Polymophism
    4. Composition

    Screenshot 2019-11-11 at 10 21 38

    In this challenge you will create 3 classes

    1. Super class called Animal
    2. Dog and Cat class which both extends Animal class (a dog is an animal and a cat is an animal)
    3. Dog and Cat class should only have 1 function, which is their own implementation of the sound() function. This is polymorphism
    4. a Home class. But we’ll talk about that later…
    // Java

? dog = new Dog()

dog.eat()    // -> 'Rax eats'
dog.sounds() // -> 'Dog barks'

? cat = new Cat()

cat.eat()    // -> 'Stormy eats'
cat.sounds() // -> 'Cat meows'

    // Javascript

var dog = new Dog();

dog.eat(); // -> 'Rax eat'
dog.sounds();// -> 'Dog barks'

var cat = new Cat();

cat.eat();// -> 'Stormy eats'
cat.sounds();// -> 'Cat meows'

    Now let’s add composition. Make a new class called Home. Lots of people have dogs and cats in their homes. Home should have a function called adoptPet that takes any Animal as an input. The new pet should be stored in the Home object in an array/list. The Home object should also have a function called makeAllSounds. It should work like this:

    // Java

Home home = new Home()
? dog1 = new Dog()
? dog2 = new Dog()
? cat = new Cat()

home.makeAllSounds() // this doesn't do anything
home.adoptPet(dog1)
home.makeAllSounds()
// this prints:
// Dog barks

home.adoptPet(cat)
home.makeAllSounds()
// this prints:
// Dog barks
// Cat meows

home.adoptPet(dog2)
home.makeAllSounds()
// this prints:
// Dog barks
// Cat meows
// Dog barks

    // Javascript

var home = new Home();
var dog1 = new Dog();
var dog2 = new Dog();
var cat = new Cat();


home.makeAllSounds();// this doesn't give/return any result/data
home.adoptPet(dog1);
home.makeAllSounds();
// this prints :
// Dog barks

home.adoptPet(cat);
home.makeAllSounds();
// this prints :
// Dog barks
// Cat meows

home.adoptPet(dog2);
home.makeAllSounds();
// this prints :
// Dog barks
// Cat meows
//Dog barks

    Up for a Challenge?

    This section is not compulsory. If you do this we’ll think you’re cool.

    Add some functionality to adoptPet so that an error/exception gets raised if you try to adoptThe same pet twice

    eg:

    home.adoptPet(dog1) // totally ok
home.adoptPet(dog1) // not ok at all
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