How to implement singly linked list in Java

[ravipankaj]

package com.ds.algorithms.linkedlist.SLLcustomImplement;
/** * @Author pankaj * @create 4/11/21 6:19 PM */
public class Node {
int data;
Node next;
}
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package com.ds.algorithms.linkedlist.SLLcustomImplement;
/**
* @Author pankaj
* @create 4/11/21 6:25 PM
*/
public class LinkedList {
Node head;// first Node
public void add(int data) {
// create Node before add it to LL
Node node=new Node();
node.data=data;
node.next=null;
// if you are adding first node, List is empty
if (head == null)
{
head=node;
}
// if head(first node is already added
else {
Node travers=head;// to traverse Node, to hold temp data
while (travers.next!=null)
{
travers=travers.next;// going to next node
}
// after reaching to last node
travers.next=node;// newly created Node is pointing
}
}
// add at first
public void addAtFirst(int data)
{
Node node=new Node();
node.data=data;
node.next=null;
node.next=head; // newly created next value will be previous head node
// change newly created Node to Head
head=node;
}
// addAt index
public void addAtIndex(int index,int data)
{
Node node=new Node();
node.data=data;
node.next=null;
// add Node to 0th index — .> add it to first Location
if(index==0)
{
addAtFirst(data);
}else {
Node n = head;
for (int i = 0; i < index — 1; i++) {
n = n.next;
}
node.next = n.next;// change ref, index-1 Node to newly created Node
n.next = node;
}
}
// delete value
public void deleteAt(int index)
{
if(index==0)
{
head=head.next;
} else {
Node n=head;
Node nRef=null;
for (int i=0;i<index-1;i++) // reach to that specific index
{
n=n.next;
}
// store ref of next Node of index element
nRef=n.next;
n.next=nRef.next;
System.out.println(“ Deleted : INDEXED “+ index+” DATA “+nRef.data);
}
}
// display method
public void display()
{
Node node=head;
while (node.next !=null)
{
System.out.print(node.data+” -> “);
node=node.next;// going to next node
}
System.out.print(node.data); // print last Node
}
}
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package com.ds.algorithms.linkedlist.SLLcustomImplement;
/**
* @Author pankaj
* @create 4/11/21 6:21 PM
*/
public class RunLinkedList {
public static void main(String[] args) {
LinkedList linkedList=new LinkedList();
linkedList.add(10);
linkedList.add(45);
linkedList.add(78);
linkedList.addAtFirst(520);
linkedList.addAtIndex(3,300);
linkedList.addAtIndex(0,100);
linkedList.display();
linkedList.deleteAt(1);
linkedList.display();
}
}