Don't know what interfaces or pure virtual functions are. Ask yourself, "what does the generic animal say?"

ylevis.cpp

/* 
Someone on reddit asked is the point of pure virtual function in c++.
Here was my response
@kuberlog the [CyberRanger](https://www.youtube.com/channel/UChsxOQf3j6Jw_BbzWcsIQPg)
*/

Vector<Animal> animals = getZoo();
for(auto it = animals.begin(); it != animals.end(); it++) {
    it->vocalize()
}

/* Prints the following:
    "Dog goes woof
     Cat goes meow
     Bird goes tweet
     Mouse goes squeek
     
     Cow goes moo
     Frog goes croak
     Elephant goes toot
     Ducks say quack
     Fish go blub
     Seal goes ow, ow, ow"

...but there is one sound that no one knows...
What does the generic Animal say?
*/