Hello guys 
What’s up
I’d like to know if someone can explain me how to use interfaces and abstract classes, why and when. I’d like to explain me this topic in details if possible and I’d be glad if you can provide me with some code ( a lot of cod if possible ). I really want to understand how to use them. As far as I know its very useful in API but dont know much about it. All the information I get is from JAVA, C# and so on.
Thanks ^^
g3n1u5