Implement the functions given, instructions of what each function needs to do is given in their respective comments. Only need a smart_ptr.h file. ```cpp// object will be created. This new copy will be the// object that this smart_ptr points and its reference// count will be one.int ref_count() const;// Returns the reference count of the pointed to data.T& operator*();// The dereference operator shall return a reference to// the referred object. Throws null_ptr_exception on// invalid access.T* operator->();// The arrow operator shall return the pointer ptr_.// Throws null_ptr_exception on invalid access.~smart_ptr(); // deallocate all dynamic memoryprivate: T* ptr_; // pointer to the referred object int* ref_; // pointer to a reference count};```### ExplanationThis code represents a simplified implementation of a smart pointer in C++. A smart pointer is a class that ensures that dynamically allocated memory is properly managed, and automatically deallocates memory when it's no longer needed. This helps in avoiding memory leaks.- **int ref_count() const;** - This member function returns the number of references pointing to the current object. It's essential in managing memory to know how many times an object is being used before deciding when to delete it.- **T& operator*();** - This function overloads the dereference operator `*`, allowing access to the object pointed to by the smart pointer. It throws an exception `null_ptr_exception` if an attempt is made to access an object that doesn't exist.- **T* operator->();** - This function overloads the arrow operator `->`, which allows the smart pointer to behave like a pointer. It returns the pointer `ptr_`, and like the dereference operator, it throws `null_ptr_exception` if invalid access is attempted.- **~smart_ptr();** - The destructor deallocates all dynamic memory managed by the smart pointer, preventing memory leaks.- **private variables:** - `T* ptr_;`: This is a pointer to the object being managed. - `int* ref_;`: This tracks the number of references (or smart pointers) pointing to the same object, enabling shared ownership management.``` **Requirements/Hints**Here are some of the requirements for writing the class. Test the implemented member functions to verify their basic functionality, and also how much of the desired semantics that is achieved by this implementation, and also if there are any undesired effects.1. The `null_ptr_exception` is an exception that you will define, it should be derived from an STL exception.2. Label the above member functions as `noexcept` where appropriate.3. You may add additional member functions, if you'd like.4. Recognize that move constructors/assignments result in the reference count remaining the same, hence there's no need to change it.5. Think about writing as exception safe code as possible. What type of guarantees should each member function have?

Answered: int ref_count () const; // Returns the…

Computer Networking: A Top-Down Approach (7th Edition)

7th Edition

ISBN:9780133594140

Author:James Kurose, Keith Ross

Publisher:James Kurose, Keith Ross

Chapter1: Computer Networks And The Internet

Section: Chapter Questions

Problem R1RQ: What is the difference between a host and an end system? List several different types of end...

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Question

Implement the functions given, instructions of what each function needs to do is given in their respective comments. Only need a smart_ptr.h file.

```cpp
// object will be created. This new copy will be the
// object that this smart_ptr points and its reference
// count will be one.

int ref_count() const;
// Returns the reference count of the pointed to data.

T& operator*();
// The dereference operator shall return a reference to
// the referred object. Throws null_ptr_exception on
// invalid access.

T* operator->();
// The arrow operator shall return the pointer ptr_.
// Throws null_ptr_exception on invalid access.

~smart_ptr(); // deallocate all dynamic memory

private:
T* ptr_; // pointer to the referred object
int* ref_; // pointer to a reference count
};
```

### Explanation

This code represents a simplified implementation of a smart pointer in C++. A smart pointer is a class that ensures that dynamically allocated memory is properly managed, and automatically deallocates memory when it's no longer needed. This helps in avoiding memory leaks.

- **int ref_count() const;**
- This member function returns the number of references pointing to the current object. It's essential in managing memory to know how many times an object is being used before deciding when to delete it.

- **T& operator*();**
- This function overloads the dereference operator `*`, allowing access to the object pointed to by the smart pointer. It throws an exception `null_ptr_exception` if an attempt is made to access an object that doesn't exist.

- **T* operator->();**
- This function overloads the arrow operator `->`, which allows the smart pointer to behave like a pointer. It returns the pointer `ptr_`, and like the dereference operator, it throws `null_ptr_exception` if invalid access is attempted.

- **~smart_ptr();**
- The destructor deallocates all dynamic memory managed by the smart pointer, preventing memory leaks.

- **private variables:**
- `T* ptr_;`: This is a pointer to the object being managed.
- `int* ref_;`: This tracks the number of references (or smart pointers) pointing to the same object, enabling shared ownership management.
```

**Requirements/Hints**

Here are some of the requirements for writing the class. Test the implemented member functions to verify their basic functionality, and also how much of the desired semantics that is achieved by this implementation, and also if there are any undesired effects.

1. The `null_ptr_exception` is an exception that you will define, it should be derived from an STL exception.
2. Label the above member functions as `noexcept` where appropriate.
3. You may add additional member functions, if you'd like.
4. Recognize that move constructors/assignments result in the reference count remaining the same, hence there's no need to change it.
5. Think about writing as exception safe code as possible. What type of guarantees should each member function have?

Expert Solution

Step 1

First of all you have not mentioned anywhere that templating is used in the code. So please mention it next time before uploading the question. First of all before asking this question you should have good understanding of pointers and class. these two are the prerequisites for this question. In the next step I have provided the code.