A linked list is a data structure that consists of a sequence of elements, each of which is connected to the next element by a pointer. In C++, a linked list can be implemented using the template class "list" from the Standard Template Library (STL). In this article, we will discuss the basics of linked lists, how to create and manipulate them in C++, and the advantages and disadvantages of using linked lists in comparison to other data structures.
A linked list is made up of nodes, each of which contains data and a pointer to the next node. The first node in the list is called the head, and the last node is called the tail. The tail node's pointer points to null, indicating the end of the list. There are two types of linked lists: singly linked lists and doubly linked lists. In a singly linked list, each node only has a pointer to the next node, while in a doubly linked list, each node has a pointer to both the next and previous nodes.
Creating a linked list in C++ is simple using the "list" class from the STL. To create a list, you simply need to declare a variable of type "list" and specify the data type of the elements that the list will hold. For example, to create a list of integers, you would write:
list<int> myList;
Once the list is created, you can add elements to it using the "push_back" function, which adds an element to the end of the list. For example, to add the integers 1, 2, and 3 to the list, you would write:
myList.push_back(1); myList.push_back(2); myList.push_back(3);
To access the elements of the list, you can use an iterator, which is an object that can be used to traverse the list. To create an iterator, you use the "begin" and "end" functions, which return iterators pointing to the first and last elements of the list, respectively. For example, to print out all the elements of the list, you would write:
list<int>::iterator it; for (it = myList.begin(); it != myList.end(); it++)
{
cout << *it << endl;
}
In addition to the "push_back" function, the "list" class also has several other functions for manipulating the list, including "push_front" (which adds an element to the front of the list), "pop_back" (which removes the last element of the list), and "pop_front" (which removes the first element of the list).
One of the advantages of using linked lists is that they can be easily manipulated by inserting or deleting elements at any position in the list. This can be done in constant time, regardless of the size of the list. In contrast, with an array, inserting or deleting elements at any position other than the end requires shifting all the elements after the inserted/deleted element, which takes linear time.
Another advantage of linked lists is that they do not have a fixed size, unlike arrays. This means that a linked list can grow or shrink dynamically as elements are added or removed. This can be useful in situations where the number of elements in a data structure is not known in advance or may change frequently.
However, linked lists also have some disadvantages. One is that they use more memory than arrays because each element in a linked list contains not only the data but also
In C++, there are several types of linked lists that can be implemented, including singly linked lists, doubly linked lists, and circular linked lists.
Singly linked list: In a singly linked list, each node only has a pointer to the next node. This means that you can only traverse the list in one direction, from the head to the tail.
Doubly linked list: In a doubly linked list, each node has a pointer to both the next and previous nodes. This means that you can traverse the list in both directions, from the head to the tail and from the tail to the head.
Circular linked list: A circular linked list is similar to a singly or doubly linked list, but the last node in the list points back to the first node, forming a loop. This can be useful in certain applications, such as a circular buffer.
The "list" class from the Standard Template Library (STL) in C++ implements a doubly linked list. It provides a range of member functions to manipulate the list and make it easy to use.
It's important to note that, Linked List can also be implemented using classes, where each node of the linked list is an object of a custom class. This allows for a more fine-grained control over the list and can be useful in certain situations where the built-in "list" class may not provide the required functionality.
