Question

Give the definitions for the member function add_value, the copy constructor, the overloaded assignment operator, and the destructor for the following class. This class is intended to be a class for a partially filled array. The member variable number_used contains the number of array positions currently filled. The other constructor definition is given to help you get started. #include

Short answer

# Answer Here are the definitions for the required member function, copy constructor, overloaded assignment operator, and destructor for PartFilledArray class: 1. add_value definition: ```cpp void PartFilledArray::add_value(double new_entry) { if (number_used < max_number) { a[number_used] = new_entry; number_used++; } else { cout << "The array is full. Cannot add a new value." << endl; } } ``` 2. Copy constructor definition: ```cpp PartFilledArray::PartFilledArray(const PartFilledArray& object) { max_number = object.max_number; number_used = object.number_used; a = new double[max_number]; for (int i = 0; i < number_used; ++i) { a[i] = object.a[i]; } } ``` 3. Overloaded assignment operator definition: ```cpp PartFilledArray& PartFilledArray::operator=(const PartFilledArray& right_side) { if (this == &right_side) { return *this; } delete[] a; max_number = right_side.max_number; number_used = right_side.number_used; a = new double[max_number]; for (int i = 0; i < number_used; ++i) { a[i] = right_side.a[i]; } return *this; } ``` 4. Destructor definition: ```cpp PartFilledArray::~PartFilledArray() { delete[] a; } ```

Step-by-step solution

Copy constructor definition

To create a deep copy of the given array, we need to allocate new memory for the object's array, copy the elements from the source object, and set the max_number and number_used variables. PartFilledArray::PartFilledArray(const PartFilledArray& object) { max_number = object.max_number; number_used = object.number_used; a = new double[max_number]; for (int i = 0; i < number_used; ++i) { a[i] = object.a[i]; } }

Member function add_value definition

For the add_value function, we need to check if there is enough space in the array to add the new value. If there is available space, add the new value to the array at the position indicated by number_used, and increment number_used. void PartFilledArray::add_value(double new_entry) { if (number_used < max_number) { a[number_used] = new_entry; number_used++; } else { cout << "The array is full. Cannot add a new value." << endl; } }

Overloaded assignment operator definition

For the overloaded assignment operator, we need to do a deep copy of the right_side object into the object being assigned to. We also need to check whether it is a self-assignment case. PartFilledArray& PartFilledArray::operator=(const PartFilledArray& right_side) { if (this == &right_side) { return *this; } delete[] a; max_number = right_side.max_number; number_used = right_side.number_used; a = new double[max_number]; for (int i = 0; i < number_used; ++i) { a[i] = right_side.a[i]; } return *this; }

Destructor definition

The destructor deallocates the dynamically allocated memory used by the array a. PartFilledArray::~PartFilledArray() { delete[] a; }

Key concepts

Copy Constructor

In C++ programming, a copy constructor is used to create a new object that is a copy of an existing object. Specifically, when dealing with a partially filled array class, the copy constructor ensures a deep copy of the array contents, rather than just copying the reference.

For example, if you have an instance of the class PartFilledArray and you want to create a new object that is an exact replica, the copy constructor comes into play. It will allocate new memory to the new object and then copy each filled element from the original array.

This process avoids issues that would arise from having two objects pointing to the same memory location, which can lead to unexpected behavior or security vulnerabilities. It's crucial for managing resources in classes that handle direct memory management, like those with dynamic memory allocation.

Overloaded Assignment Operator

The overloaded assignment operator, often represented as =, plays a critical role in managing object states in C++. When you want to assign one instance of a class to another, you are not just copying values but ensuring that any dynamic memory is correctly handled.

For the PartFilledArray class, overloading this operator involves cleaning up any existing memory the array might have used, and then creating a deep copy of the right-hand side object's array into the left-hand side object. It's also vital to prevent self-assignment, which can cause accidental deletion of data.

By handling these operations properly, the overloaded assignment operator ensures that each object instance maintains its own unique state, guarding against potential memory leaks and ensuring program stability.

Destructor

A destructor serves a singular but vital purpose in the lifecycle of a C++ object: it cleans up. When an object goes out of scope or is explicitly deleted, the destructor is called to perform necessary cleanup tasks, such as releasing memory or other resources.

In our PartFilledArray class, the destructor is essential because the class manages a dynamic array. As such, it must delete[] the allocated array to prevent memory leaks, which can exhaust memory resources and cause a program to crash.

Destructors are a cornerstone of C++'s RAII (Resource Acquisition Is Initialization) idiom, ensuring that all resources acquired by an object are released when the object's lifetime ends, thus upholding the integrity of the program's memory usage.

Member Functions

In C++, member functions are functions that belong to a class. They define the behavior of objects created from the class and can access and modify object data. Member functions, such as add_value for the PartFilledArray class, are tailored to meet the specific needs of the class they are a part of.

The add_value member function is designed to add a new entry to the partially filled array, but only if there's sufficient space. It demonstrates how member functions can work with the internal state of objects, manipulating and utilizing member variables to achieve the desired functionality.

Member functions provide a clean interface for object interactions and are fundamental in encapsulating and protecting object data, following the principles of object-oriented design.