When it comes to programming, data structures are essential components of programming that help in arranging, manipulating, and even storage of data in a more effective manner. The best algorithms and programs are built around data structures. There are several types of data structures out there and among the most popular ones are the Linked list, stack and queue especially in C++. This helps programmers organize the data in a manner that allows fast retrieval, insertion, and deletion of the desired information. In this article, we will begin by introducing these three data structures with an overview of what they are, their specific applications, and how these structures work in C++.

The Linked List

The linked list is a clear example of the single most common construction used in C++, as it is easy to understand and implement. In a linked list, a node contains a single application which is to point to the next node. This construction eliminates the requirement for arrays where elements must be organized in one memory location. One advantage of Linked lists is the ease and flexibility with which nodes can be added and deleted. In other words, deleting an element does not constitute removing a node; rather, it entails freeing the node that points to the element to be deleted, thus allowing shifts in address resources.

A node in a linked list consists of two main parts:

1. Data: a single value that the node has been assigned.

2. Pointer: points towards the next element of the list, thereby making the next element part of the list.

There are different types of linked lists such as:

- Singly Linked List: This type of list only allows the nodes to point to the next node, with no pointer back to the previous node.

- Doubly Linked List: Every node contains a pointer to its next and its previous node, allowing the traversal in both directions.

- Circular Linked List: By utilizing the fact that the last node in the list can always point back towards the first node, a structure which is circular in nature can be created.

The most notable feature of any linked list is that it is dynamic in nature. It differs from arrays in the sense that while arrays have a set number of items, linked lists grow or reduce according to their demand. This makes them the most suitable linked data structure depending on the conditions, where the size of the dataset keeps on changing.

The Stack

A Stack is a type of data structure that can only add and remove elements from the end of the increasingly ordered nodes and sacrifices the more primitive structure’s breadth first property allowing for more narrow cases over the most recently added or last added as the first to go out and as the last functionality to come in. Looking at a stack can be as though you were to look at how plates are laid out at a seating area in a restaurant where the last plate that was added will be the first one to be taken to use in terms of removing pots. That is how stacks work too. For a stack only the last added item can be viewed. There are several permutations of this structure but one of the more frequently used is when times are unstable in terms of what needs to be shown or when the state can be saved in a singular form.

The main operations on a stack include the following:

1. Push: If you want to add an item to the stack, this is the action that you take.

2. Pop: This process returns the item at the top of the stack while also removing its content.

3. Peek: This process allows the user to look at the topmost item of the stack while in theory, it does not take it out.

4. IsEmpty: This process contains the queries that can determine whether a given stack is empty or not.

Now, what comes to our mind when we think of a stack, we can consider a few examples: - Function calls: In many programming languages, function calls are handled with the help of a stack, as is the case with most other data structures. Each time a function is called, all the state information associated with that function (local variables, the return address, etc.) is transferred to the stack. After the function ends, the information in the stack is returned to the caller.

- Storing Mechanism: When it comes to assaying mathematical expressions, there are instances when there is a need to convert infix expressions to postfix or prefix expressions and much more can be done using stacks.

- Relieving burden of undo: In word processors, graphic editors, etc, suppressing the most recent one or the last one can last up to a pool of actions. This can be done by expanding a stack which is a pool of actions that were most recent.

In C++, linked lists and arrays are used to construct stacks whereas, in the Standard Template Library (STL) of C++, stack classes are included by default.

The Queue

A queue is an example of a linear list that is accessible according to the ‘First in First out’ or ‘FIFO’ rule. Queues resemble standing in a line for a box office ticket — the person who stands first will be served first. Basically, in queues or queues, q1 or q2, the element that was first enqueued will also be the first one to get dequeued. In computer science, however, queues come in handy primarily when processes need to occur in the order the data was received — for example, when scheduling execution or asynchronous event handlers.

A queue has the following primary operations:

1. Enqueue: This operation adds an element to the end of the queue.

2. Dequeue: This operation removes the element from the front of the queue.

3. Front: This particular operation serves to provide access to the item located at the front of the line without removing it from that position.

4. Addressed And IsEmpty: This operation helps in checking the status of the queue being empty.

Queues Find Application in Various Areas Such As: - Task Queues: Operating Queues refer to the management of tasks within a multi-tasking operating system. Tasks that the system needs to get done are set in a line and are executed on a first come first serve basis.

- When one or more documents that are intended for the printer are sent: It is put in a line to be printed in the order in which it was sent to the printer.

- BFS or Breadth- First Search: BFS is a technique that operates all the nodes of a graph starting with the node in the outermost layer and going one level deeper with deeper becoming more and more inaccessible each level, efficiently making use of the other nodes until all relevant nodes are accessible or all nodes which can be reached on that level are exhausted, it makes use of Queues.

Apart from the English Queues might also be represented by arrays and linked lists, Queues like stacks are part of the STL library in C++. Therefore, it is easier and more effective to handle them in C++.

Analysing Linked Lists, Stacks, and Queues

The main differences between Linked Lists, Stacks and Queues are their structures and the operations that they enable. The main purpose of these data structures is to categorize or arrange data in an efficient manner. The main differences between these data structures are access patterns:

- Linked List: Offers a certain degree of freedom in terms of inclusion and exclusion but does not provide a definite order of access. Nodes are included in the free form and can also be used to construct other data structures like stacks and queues.

- Stack: The last-in-first-out mechanism assists in using the data which is required most recently, allowing easier fashioning of the data which is most recently at the top, this is useful since sometimes only the topmost element is required and that provides a simple and efficient solution.

- Queue: The first in first out mechanism supports the real-life event of which elements need to be processed when they are received and does so in a logical way.