Question

Explain how in a protected inheritance, the members of the base class are inherited by a derived class.

Short answer

Protected inheritance makes base class public and protected members protected in the derived class.

Step-by-step solution

Understanding Protected Inheritance

In protected inheritance, the public and protected members of the base class become protected members of the derived class. Private members of the base class still remain inaccessible to the derived class.

Identify Members for Inheritance

Determine which members of the base class are public and protected. These members will be inherited as protected members in the derived class, meaning they'll be accessible to the derived class and its subclasses, but not to outsiders.

Private Members Management

Acknowledge that private members of the base class do not change with inheritance type. They remain private and inaccessible to any derived classes, maintaining encapsulation from unintended access.

Key concepts

Base Class Members

When discussing object-oriented programming, understanding the concept of base class members is fundamental. Base class members refer to variables and functions that belong to the parent or base class in a class hierarchy. These members are the building blocks, providing functionality and state that derived or child classes can utilize and build upon.

Base class members can have different levels of accessibility:

• **Public:** Members are accessible from anywhere in the program.
• **Protected:** Members are accessible within the class itself and by all derived classes, but not outside.
• **Private:** Members are accessible only within the class they are declared.

In protected inheritance, the focus is primarily on the public and protected members, which the derived class inherits as protected. This inheritance style ensures that private members stay secluded and do not interfere with the derived classes, maintaining a clear and safe inheritance chain.

Derived Class

A derived class is essentially a class built upon another class, known as the base class. It inherits the properties and behaviors of the base class, either adding new features or modifying existing ones to extend the functionality.

Think of a derived class as a specialized version of the base class. While it inherits capabilities and data from the base class, it can also have its own unique features. This allows for code reuse, reducing redundancy and enhancing maintainability.

In protected inheritance, the derived class gains access to the base class’s public and protected members, which become protected in the derived class. This setup helps protect the encapsulated data while providing a framework for further extension. Derived classes can also further inherit their own members to other subclasses, continuing the inheritance chain.

Encapsulation

Encapsulation is a core principle of object-oriented programming. It refers to the bundling of data and the methods that operate on that data within a single unit, or class. By doing this, we can limit access to some of the components of an object and prevent the accidental modification of data.

Encapsulation is often accomplished using access specifiers, which control the visibility of class members to other parts of the program. By marking members as private, they remain hidden from external classes, promoting a high degree of control over internal data. Protected and public members can be accessed by derived classes and other elements as specified.

In the context of inheritance, protected inheritance particularly emphasizes encapsulation. It ensures that the derived class inherits only what it can appropriately handle and utilize, maintaining a clear boundary of accessed and modified data.

Access Control

Access control is a fundamental aspect of class design in object-oriented programming. It determines which parts of your code can interact with certain class members. This control is managed through access specifiers like public, protected, and private, allowing you to define how much information is exposed or restricted.

Protected inheritance modifies access control by changing how inherited members are accessed. Public and protected members of the base class become protected in the derived class, limiting external access while providing controlled access within the class hierarchy.

This method offers a balance between openness and restriction, helping to maintain a controlled environment for class interaction. Each access level ensures that your programs can grow in complexity without sacrificing security and integrity, making your code more robust and easier to maintain.