抽象（OOP编程）

Abstraction is a process of managing complexity. In programming, it involves creating a simplified representation of a system or component. In OOP, this is primarily done using abstract classes and interfaces. An abstract class is a class that cannot be instantiated on its own and is meant to be subclassed. It can contain abstract methods (methods without a body) that subclasses must implement. An interface is a similar concept but is purely abstract; it can only define 方法 signatures, not implementations. A class can then ‘implement’ an interface, promising to provide the functionality defined in it.

This allows programmers to define a common contract or API that multiple different classes can adhere to. For example, an interface ‘Storable’ could define ‘save()’ and ‘load()’ methods. Different classes like ‘Document’, ‘Image’, and ‘UserSettings’ could all implement the ‘Storable’ interface, each providing its own logic for saving and loading. Code that works with ‘Storable’ objects doesn’t need to know the specific type of object it’s dealing with; it only needs to know that it can call ‘save()’ and ‘load()’. This decouples the client code from the specific implementations, making the system more modular, flexible, and easier to understand at a high level.