Question

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

Short answer

Answer: When a member function's body is written inside a class declaration, it is called an inline function.

Step-by-step solution

Understand the concept of member functions

Member functions are functions that are declared within a class definition. They are used to modify or access the data members (variables) of an object, which is an instance of that class.

Identify the type of member function with body inside the class declaration

When a member function's body is written inside a class declaration, it means the function definition is directly provided within the class definition itself. Such functions are called inline functions.

Explain the benefits of inline functions

Inline functions are used to reduce the overhead of function calls, as the function is directly inserted into the code rather than being called separately. This can improve the performance of the code, especially for small and frequently called functions.

Key concepts

Member Functions in C++

In the realm of C++, member functions can be thought of as the actions that an object of a class can perform. They are integral to the idea of encapsulation, one of the fundamental principles of object-oriented programming. Encapsulation enables us to bundle data and the functions that operate on that data within a single unit, namely a class.

Member functions have access to the private and protected data members of their class and are commonly used to get (accessors) or set (mutators) the values of those members. Moreover, they can be used to perform operations specific to the class's functionality, making them a powerful tool for constructing orderly and modular code.

Here are some key aspects of member functions in C++:

• Accessibility: They can be public, private, or protected, controlling the scope of accessibility from outside the class.
• Const Member Functions: Declaring a function as 'const' assures that it won't modify the object it's called on, increasing reliability and predictability.
• Static Member Functions: These functions belong to the class as a whole rather than any object instance and can be called without an object.

Member functions ensure that the internal state of an object can be carefully controlled and manipulated, preserving the integrity of the object.

Class Declaration Essentials

A class declaration in C++ is a blueprint for creating objects, a core concept of object-oriented programming. It provides a template for defining the structure and behaviors (member functions) of objects that belong to the class. Think of a class as a custom data type that encapsulates data and the functions which work with that data.

When declaring a class, you are designing a new type that can include a combination of variables (data members), functions (member functions), and even other types (e.g., enums, other classes). Once a class is declared, it can be instantiated to create objects with properties and behavior as defined by its attributes and member functions.

The basic structure of a class declaration in C++ might look like this:

class MyClass {public:  MyClass(); // constructor  void MyFunction(); // member functionprivate:  int myData;  // data member};

Within this template:

• The public section is accessible by all parts of a program.
• The private section is only accessible within the class itself.
• Constructors are special member functions called when an instance of the class is created.

Understanding class declarations is fundamental to harnessing the full potential of C++ as it sets the stage for advanced features like inheritance, polymorphism, and encapsulation.

Understanding C++ Function Calls

A function call in C++ is a point in the program where we invoke or 'call' a function to execute. When a function is called, the program control gets transferred to the called function. This is an essential concept because functions allow a programmer to break down complex problems into smaller, more manageable, and reusable pieces of code.

Here’s what happens during a function call in C++:

• The actual parameters (arguments) are passed to the function’s formal parameters.
• The function body is executed.
• Upon reaching the return statement, or the end of the function body, the program control returns to the point where the function was called and continues with the next statement.
• If the function returns a value, it can be used immediately in expressions or stored in a variable.

In the context of member functions, the syntax for calling a function might look like this:

MyClass myObject;myObject.MyFunction();

Here, MyFunction is a member of MyClass, and we're calling it on an instance of MyClass named myObject. For an inline function, this call is particularly efficient because inline functions are expanded at compile time, replacing the function call with the actual function code, thus reducing the overhead that typically comes with a function call.