Question

Give a definition for a class SmartBut that is a derived class of the base class Smart, which we reproduce for you here. Do not bother with winclude directives or namespace details. class smart \\{ public: Smart( ) : void print_answer() const; protected: int a : int \(b\) \(y\) This class should have an additional data field, crazy, that is of type bool, one additional member function that takes no arguments and returns a value of type \(b o o l,\) and suitable constructors. The new function is named is_crazy. You do not need to give any implementations, just the class definition.

Short answer

Answer: In the derived class SmartBut, an additional data field named 'crazy' with type bool is included, as well as an additional member function named 'is_crazy' that takes no arguments and returns a bool value.

Step-by-step solution

Class Definition: SmartBut

```cpp class SmartBut : public Smart { public: // Constructors SmartBut() : Smart(), crazy(false) {} SmartBut(int a, int b, int y, bool crazy) : Smart(a, b, y), crazy(crazy) {} // Member function bool is_crazy() const; protected: // Additional data field bool crazy; }; ``` In this class definition, we have derived SmartBut from the base class Smart. We have added the additional data field 'crazy' with type bool, as well as member function 'is_crazy' returning a bool value. We have also included suitable constructors for this class.

Key concepts

Class Derivation in C++

In C++ programming, class derivation is a fundamental concept of object-oriented programming (OOP). It allows a new class to inherit properties and behaviors from an existing class. In the provided exercise, the class SmartBut is derived from the class Smart, using the syntax class SmartBut : public Smart. This indicates that SmartBut is a derived class, or a subclass, and Smart is the base class, or superclass.

Through inheritance, SmartBut gains access to the public and protected members of Smart. It's important to note that private members would not be accessible. Derivation facilitates code reuse and the ability to create more specific classes from more general ones.

In class SmartBut, constructors are defined that initialize both the inherited members and the new member variable crazy. This shows how constructors in derived classes call their base class constructors to ensure all parts of the object are properly initialized.

Object-Oriented Programming

Object-oriented programming (OOP) is a programming paradigm based on the concept of 'objects', which can contain data and code: data in the form of fields (often known as attributes or properties), and code in the form of procedures (known as methods or member functions). OOP allows developers to create modular and reusable code.

In the context of the exercise, SmartBut's ability to derive from Smart demonstrates OOP's principle of inheritance. OOP facilitates four main principles: encapsulation, abstraction, inheritance, and polymorphism.

• Encapsulation: Bundling of data with the methods that operate on it.
• Abstraction: Hiding complex realities while exposing only the necessary parts.
• Inheritance: Extending functionality of existing classes.
• Polymorphism: Accessing objects of different but related types through a common interface.

Understanding these principles is crucial for solving OOP-based exercises and creating well-structured, efficient code.

Member Functions in OOP

Member functions are the operations that an object from a class can perform. They are essential in defining the behavior of the class. In our exercise, the member function is_crazy is added to the derived class SmartBut to perform a specific action related to the SmartBut object.

Member functions can be of several types: constructor functions for initializing objects, destructor functions for cleanup tasks, mutators (also known as setters) for setting object state, accessors (also called getters) for retrieving object state, and other utility functions.

The is_crazy function is an example of an accessor: it provides a safe way to obtain the value of private or protected data members, in this case, the boolean field crazy. Using member functions like this not only ensures data encapsulation but also allows the logic associated with accessing the data to be centrally managed and consistently applied across all instances of the class.