Java Program to search an element in a singly linked list

In this program, we need to search a node in the given singly linked list.

Identity Matrix

To solve this problem, we will traverse through the list using a node current. Current points to head and start comparing searched node data with current node data. If they are equal, set the flag to true and print the message along with the position of the searched node.

For e.g., In the above list, a search node says 4 which can be found at the position 4.

Algorithm

Create a class Node which has two attributes: data and next. Next is a pointer to the next node in the list.
Create another class SearchLinkedList which has two attributes: head and tail.
addNode() will add a new node to the list:
- Create a new node.
- It first checks, whether the head is equal to null which means the list is empty.
- If the list is empty, both head and tail will point to a newly added node.
- If the list is not empty, the new node will be added to end of the list such that tail's next will point to a newly added node. This new node will become the new tail of the list.

a. searchNode() will search for a node in the list:

Variable i will keep track of the position of the searched node.
The variable flag will store boolean value false.
Node current will point to head node.
Iterate through the loop by incrementing current to current.next and i to i +
Compare each node's data with the searched node if a match is found, set a flag to true.
If the flag is true, display the position of the searched node.
Else, display the message "Element is not present in the list".

a. display() will display the nodes present in the list:

Define a node current which will initially point to head of the list.
Traverse through the list till current points to null.
Display each node by making current to point to node next to it in each iteration.

public class SearchLinkedList { //Represent a node of the singly linked list class Node{ int data; Node next; public Node(int data) { this.data = data; this.next = null; } } //Represent the head and tail of the singly linked list public Node head = null; public Node tail = null; //addNode() will add a new node to the list public void addNode(int data) { //Create a new node Node newNode = new Node(data); //Checks if the list is empty if(head == null) { //If list is empty, both head and tail will point to new node head = newNode; tail = newNode; } else { //newNode will be added after tail such that tail's next will point to newNode tail.next = newNode; //newNode will become new tail of the list tail = newNode; } } //searchNode() will search for a given node in the list public void searchNode(int data) { Node current = head; int i = 1; boolean flag = false; //Checks whether list is empty if(head == null) { System.out.println("List is empty"); } else { while(current != null) { //Compares node to be found with each node present in the list if(current.data == data) { flag = true; break; } i++; current = current.next; } } if(flag) System.out.println("Element is present in the list at the position : " + i); else System.out.println("Element is not present in the list"); } public static void main(String[] args) { SearchLinkedList sList = new SearchLinkedList(); //Add nodes to the list sList.addNode(1); sList.addNode(2); sList.addNode(3); sList.addNode(4); //Search for node 2 in the list sList.searchNode(2); //Search for a node in the list sList.searchNode(7); }}

Java Program to search an element in a singly linked list

Algorithm

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Program:

Java Singly Linked List Programs

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