What is inheritance in C++?

Inheritance in C++ is a fundamental concept in object-oriented programming that allows a class to inherit properties and behaviors (attributes and methods) from another class. This relationship creates a hierarchy where the class that is inheriting is called the derived class, and the class it inherits from is called the base class. By utilizing inheritance, the derived class can reuse existing code and extend or modify functionalities of the base class, promoting code reusability and organization.

This mechanism supports the concept of "is-a" relationships, where the derived class can be considered a specific type of the base class. For example, if you have a base class named "Animal," and a derived class named "Dog," the Dog class inherits characteristics of an Animal, while also having additional features specific to dogs.

The other options pertain to different concepts within object-oriented programming: hiding data relates to encapsulation, combining class structures refers to aggregation or composition, and destructors relate to cleanup operations when an object goes out of scope.