Expert C++

Encapsulation and the public interface

Encapsulation is a key concept in object-oriented programming. It allows us to hide the implementation details of objects from the client code. Take, for example, a computer keyboard; it has keys for letters, numbers, and symbols, each of which acts if we press on them. Its usage is simple and intuitive, and it hides a lot of low-level details that only a person familiar with electronics would be able to handle. Imagine a keyboard without keys— one that has a bare board with unlabeled pins. You would have to guess which one to press to achieve the desired key combination or text input. Now, imagine a keyboard without pins— you have to send proper signals to the corresponding sockets to get the key