Description: An open class is a fundamental concept in object-oriented programming that allows the creation of classes that can be inherited by others. This means that an open class can serve as a base for other classes, facilitating code reuse and the extension of functionalities. Open classes are essential for creating class hierarchies, where subclasses inherit attributes and methods from the parent class, thus promoting modularity and code organization. This approach not only improves code readability but also allows developers to build more complex applications more efficiently. In many programming languages, open classes are a standard feature that enables programmers to define common behaviors in a base class and then specialize them in derived classes. This encourages cleaner design and better code management, as changes in the base class are automatically reflected in subclasses, reducing code duplication and potential errors. In summary, open classes are a pillar of object-oriented programming, providing a flexible and scalable structure for software development.