Question

An overridden base class function may be called by a function in a derived class by using the _________ operator.

Short answer

Answer: Scope resolution operator

Step-by-step solution

Understand Base and Derived Classes

In object-oriented programming, base classes (also known as parent classes) define general properties and behaviors, whereas derived classes (also known as child classes) inherit properties and behaviors from the base class and might override or extend some of these properties and behaviors.

Understand Overridden Functions

An overridden function is a function in the derived class that has the same name and signature (i.e., the same number and types of arguments) as a function in the base class. When an overridden function is called on an object with the derived class type, it calls the derived class's implementation of the function, rather than the base class's implementation.

Identify the Operator to Call an Overridden Base Class Function

To call an overridden base class function from a function in a derived class, you can use the scope resolution operator, which is written as two colons (::). By putting the base class name followed by the scope resolution operator before the function name, like this: BaseClassName::FunctionName(), you tell the compiler to call the base class's implementation of the function instead of the derived class's implementation. So, the answer is the "scope resolution operator".

Key concepts

Base Class

In object-oriented programming (OOP), a base class is often referred to as the parent class. It sets the groundwork for classes derived from it, providing fundamental features and behaviors common to a set of classes.

The base class contains:

• Attributes: These are data members that hold specific types of information.
• Methods: These are functions that define behaviors and are associated with the class.

A base class is crucial because it allows code reuse and a cleaner, more organized code structure. Instead of rewriting the same code across multiple classes, you can define common elements in the base class and extend them in derived classes. By leveraging base classes, developers view their systems in layers, starting broad and narrow them down through inheritance.

Derived Class

A derived class, also known as a child class, builds upon the structure of a base class. When a new class is created out of an existing base class, it becomes a derived class. This process is called inheritance.

Derived classes contain all the features of the base class and can also introduce additional features:

• Inheritance: They inherit attributes and methods from the base class, enabling code simplification and consistent behavior.
• Customization: They can override existing functionalities of the base class or introduce new ones, tailored to their specific needs.

This approach aids in avoiding code duplication, as derived classes can utilize the base class's functionality while making specific adjustments. Derived classes enable a dynamic and flexible design, allowing software to be more modular and adaptable.

Overridden Function

An overridden function is a method in a derived class that redefines a method from the base class. This redefinition is possible when a method in a derived class has the same name and function signature as in the base class.

Overridding allows the derived class to:

• Provide a specific implementation of a method that suits its needs.
• Change or enhance how the base class's function works within its context.

When an overridden function is called on a derived class instance, the method defined in the derived class is executed instead of the base class one. To refer back to the base class function, you use the scope resolution operator (::). For instance, if you want to call the base version of a function named `display`, you might write `BaseClassName::display()`. This gives flexibility to retain or modify functions efficiently and allows maintaining the integrity of the object-oriented design.