Implement LinkedList in Java

Exercise:

Write a Java Program to implement linkedlist.

1.Implement Linkedlist

Click Here to View the Solution!
public class LinkedList {

    // create an object of Node class
    Node head;

    // static inner class
    static class Node {
        int value;
        Node next;
        Node(int d) {
            value = d;
            next = null;
        }
    }
    public static void main(String[] args) {

        // create an object of LinkedList
        LinkedList linkedList = new LinkedList();

        // assign values to each linked list node
        linkedList.head = new Node(21);
        Node second = new Node(22);
        Node third = new Node(23);
        Node fourth = new Node(24);

        // connect each node of linked list to next node
        linkedList.head.next = second;
        second.next = third;
        third.next  = fourth;

        // printing node-value
        System.out.print("LinkedList: ");
        while (linkedList.head != null) {
            System.out.print(linkedList.head.value + " ");
            linkedList.head = linkedList.head.next;
        }
    }
}
Click Here to View the Output!
LinkedList: 21 22 23 24
Click Here to View the Explanation!
  • This program depicts the procedure of creating a Linked-List.
  • For implementing linked-list, we create a class named LinkedList first.
  • After that we declare a Node type object named head.
  • The following class contains another inner-class named Node which is of static type.
  • In compliance with these properties, we declare an int type variable that’ll contain the value, and a next variable of Node, that’ll point to the next node in the list.
  • The Node constructor initializes the values to the input d and makes the next Node null for the time being.
  • In the main method we instantiate an object of LinkedList; using that object we assign a Node to the header, and create a second and third node.
  • Next step is to connect these nodes, where the second node is assigned to the next node of head, and the third node is linked to the next node to the second one.
  • Finally, the while loop prints node values as long as the head node does not become null.

2.implement using LinkedList class

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import java.util.LinkedList;

public class Linkedlist {
    public static void main(String[] args){

        // create using the LinkedList class
        LinkedList<String> languages = new LinkedList<>();

        // Add elements to LinkedList
        languages.add("Java");
        languages.addFirst("Swift");
        languages.addLast("C++");
        System.out.println("LinkedList: " + languages);
        System.out.println("First Element: " + languages.getFirst());
        System.out.println("Last Element: " + languages.getLast());
    }
}
Click Here to View the Output!
LinkedList: [Swift, Java, C++]
 First Element: Swift
 Last Element: C++
Click Here to View the Explanation!
  • This program depicts the procedure of creating a Linked-List.
  • For implementing linked-list, we use Java provided class named LinkedList.
  • In the main method, we instantiate an object of LinkedList class, i.e. of String data type.
  • To simply add elements to the LinkedList, we use add() method.
  • To add an element to the start of the LinkedList, we call addFirst() method.
  • To add an element to the end of the LinkedList, we use addLast() method.
  • After inserting elements in the List, we print these elements.
  • Here first element is fetched by calling getFirst() method, whereas the last element is retrieved by using getLast() method of LinkedList class.
  • Consider this point that we have used < > brackets to create a generic type Linked-List.
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