LinkedList

A LinkedList in Java is another type of data structure that, like an ArrayList, allows you to store and manage a collection of elements. However, unlike an ArrayList, a LinkedList is implemented as a doubly linked list, where each element (or node) in the list contains a reference to the next and previous elements. This structure provides flexibility in inserting and deleting elements but may be less efficient in random access compared to an ArrayList.

import java.util.LinkedList;
// Syntax for creating a LinkedList
LinkedList<Type> listName = new LinkedList<>();
Code language: JavaScript (javascript)

Adding Elements

1. add(element): Appends an element to the end of the list.
2. addFirst(element): Inserts an element at the beginning of the list.
3. addLast(element): Appends an element to the end of the list.

Accessing Elements

1. get(index): Retrieves the element at the specified index.
2. getFirst(): Retrieves the first element of the list.
3. getLast(): Retrieves the last element of the list.

Removing Elements

1. remove(): Removes and returns the first element of the list.
2. remove(index): Removes the element at the specified index.
3. removeFirst(): Removes and returns the first element of the list.
4. removeLast(): Removes and returns the last element of the list.

Size and Capacity

1. size(): Returns the number of elements in the list.
2. isEmpty(): Checks if the list is empty.

Other Operations

1. contains(element): Checks if the list contains a specific element.
2. clear(): Removes all elements from the list.
3. toArray(): Converts the list to an array.

import java.util.LinkedList;
public class StudentLinkedListExample {
    public static void main(String[] args) {
        // Creating a LinkedList to store student names
        LinkedList<String> studentsList = new LinkedList<>();

        // Adding students to the LinkedList
        studentsList.add("Paani");
        studentsList.add("Mahesh");
        studentsList.add("Datta");
        studentsList.add("Ganesh");
        studentsList.add("Harsha");

        // Displaying the names of students
        System.out.println("List of students:");
        for (String student : studentsList) {
            System.out.println(student);
        }

        // Adding a new student at the beginning
        studentsList.addFirst("NewStudent");

        // Displaying the updated list
        System.out.println("\nUpdated list of students:");
        for (String student : studentsList) {
            System.out.println(student);
        }

        // Removing the first student
        String removedStudent = studentsList.removeFirst();
        System.out.println("\nRemoved student: " + removedStudent);

        // Displaying the final list
        System.out.println("\nFinal list of students:");
        for (String student : studentsList) {
            System.out.println(student);
        }
    }
}

D:\>javac HashtableExample.java

D:\>java HashtableExample
Hashtable of students:
{Ganesh=104, Paani=101, Mahesh=102, Harsha=105, Datta=103}

Removed student 'Datta' with roll number: 103

Updated Hashtable of students:
{Ganesh=104, Paani=101, Mahesh=102, Harsha=105}

Does the Hashtable contain student 'Harsha'? true

Iterating over Hashtable entries using enumeration:
Student: Ganesh, Roll Number: 104
Student: Paani, Roll Number: 101
Student: Mahesh, Roll Number: 102
Student: Harsha, Roll Number: 105

Size of the Hashtable: 4

Is the Hashtable empty now? trueCode language: JavaScript (javascript)