Question

The derived class named in the following line of code is __________. class Pet : public Dog

Short answer

Answer: Pet

Step-by-step solution

Understand the class declaration syntax

In C++, a class derivation list is used to specify one or more base classes for a derived class. The syntax for a class derivation list looks like this: ```cpp class DerivedClass : access-specifier BaseClass ``` In our given line of code: ```cpp class Pet : public Dog ``` Here, "class" is a keyword that introduces the class definition, and "public" is the access-specifier that specifies the access level for the base class members.

Identify the derived class

Now, we will identify the derived class by matching the syntax with the given code. From the given line of code: ```cpp class Pet : public Dog ``` Using the class derivation syntax, we can see that `Pet` is the DerivedClass, and `Dog` is the BaseClass. Therefore, the derived class name is "Pet".

Key concepts

Derived Class

In C++, a derived class is a class that is created based on another class, called the base class. The derived class inherits the properties of the base class, meaning it can use the data members and member functions of the base class. However, these inherited components' access depends on the access specifier used when inheriting. This allows for code reuse and creates a clear hierarchical structure. When extending the functionality of a base class, the derived class can also introduce its own members, unique to it. This capability makes derived classes a powerful feature in object-oriented programming.

• Code Reuse: When a derived class extends a base class, it doesn't need to rewrite existing functionalities. This promotes efficiency and code simplicity.
• Hierarchical Structure: By using derived classes, developers can make a logical hierarchy in their programs, reflecting real-world relationships.
• Customization: While having access to base class members, a derived class can still introduce its own methods to add specific functionalities.

In our exercise's context, `Pet` acts as the derived class.

Base Class

The base class in C++ refers to the class from which properties and behavior are inherited by another class known as the derived class. It acts like a parent class and provides foundational functionalities that can be utilized or overridden by its child classes. Base classes are central to inheritance and play a crucial role in class hierarchies by allowing shared functionality.

• Foundation: The base class provides the primary functionality that other classes can expand on.
• Inheritance: Derived classes inherit data members and member functions from the base class, enabling shared functionality.
• Programming Principle: A well-established base class can often lead to a cleaner and less error-prone code.

In the given code example, `Dog` is the base class. This means any `Pet` object has access to `Dog`'s members based on the access specifier used.

Access Specifier

Access specifiers in C++ are keywords that define the accessibility of the class members to other parts of the code. There are three main types: `public`, `protected`, and `private`. These keywords help control how and when different parts of your program can interact with various class components. Understanding access specifiers is critical for maintaining a robust and well-structured code.

• Public: Members declared as `public` can be accessed from anywhere where the object is visible.
• Protected: `Protected` members are accessible within the class itself and by any derived classes.
• Private: Members with the `private` specifier can only be accessed within the defining class.

In our exercise, the keyword `public` was used before `Dog`, which means the `Dog` class members are publicly accessible to the `Pet` derived class. This means that all public members of `Dog` become public members of `Pet` as well.