Difference between Encapsulation and Abstraction

Question

I had an interview today. I had a question from OOP, about the difference between Encapsulation & Abstraction?

Answer 1

Encapsulation: Wrapping code and data together into a single unit. Class is an example of encapsulation, because it wraps the method and property.

Abstraction: Hiding internal details and showing functionality only. Abstraction focus on what the object does instead of how it does. It provides generalized view of classes.

int number = 5;
string aStringNumber = number.ToString(); 

Here, ToString() is abstraction. And how this mechanism number variable converted to string and initialize into aStringNumber is encapsulation.

Let us take a real world example of calculator. Encapsulation is the internal circuits, battery, etc., that combine to make it a calculator. Abstraction is the different buttons like on-off, clear and other buttons provided to operate it.