Question

When a member function’s body is written inside a class declaration, the function is a(n) _________ function.

Short answer

Answer: Inline

Step-by-step solution

1. Recall the term describing member functions with bodies inside class declarations

In object-oriented programming languages like C++, when a member function's body is written inside a class declaration it is referred to as an "inline" function.

2. Fill in the blank

The correct term to complete the given statement is: "inline". The completed statement is: "When a member function’s body is written inside a class declaration, the function is an inline function."

Key concepts

Member Function

A member function is a vital part of a class in object-oriented programming (OOP). It's a function that has access to the data members of a class and can be leveraged to define the behavior of objects created from the class. Unlike regular functions, member functions are called on objects, which allows them to act on the data contained within those objects.

For instance, if we consider a class called 'Book', a member function might be 'read', which allows us to perform operations related to reading a book. As member functions can directly access and modify the class's data members, they offer a convenient and effective way to manipulate object state, serving as a key mechanism of encapsulation in OOP.

It is essential to understand that member functions can be defined within the class declaration or outside it using the scope resolution operator. When defined within the class, they can be made 'inline'—a concept that allows for potentially faster execution, as the function's code will be copied to the point of call during compilation, rather than being accessed through a typical function call stack.

Class Declaration

The class declaration, in object-oriented programming, is a blueprint from which objects are created. This blueprint includes details such as which variables, known as data members, and functions, known as member functions, the objects of the class will contain.

An example of a class declaration is as follows:
class Rectangle
{
public:
    int width, height;
    void setValues(int, int);
    int area() { return width * height; }
};
In this example, 'Rectangle' is declared with data members 'width' and 'height', and a member function 'area' is defined within the class that calculates the area of the rectangle. The class declaration provides a template that dictates what each object of the class will consist of and how it's expected to behave. This creates an organized, modular approach to programming, which simplifies coding, debugging, and collaboration.

Object-Oriented Programming

Object-oriented programming (OOP) is a programming paradigm based on the concept of 'objects', which are instances of classes. These classes form the cornerstone of OOP and are defined by their member functions and data members.

Four main principles govern OOP:

• Encapsulation: Enclosing the data and functions that operate on data within a single unit or class.
• Inheritance: Creating new classes that are based on existing classes to facilitate reuse of code.
• Polymorphism: Allowing entities to take on more than one form, depending on the context.
• Abstraction: Hiding complex details and showing only the necessary features of an object.

These principles guide the creation of complex applications by enabling developers to craft objects that interact in a clear and controlled manner. OOP languages, such as C++, Java, and Python, use classes and objects to structure software in a way that is robust, easy to maintain, and scalable over time.