Linkedlist.java

import java.util.*;
class node
{
	int info;
	node ptr;
	public node(int data)
	{
		this.info=data;
		this.ptr=null;

	}
}
public class Linkedlist {
	node head;
	public Linkedlist()
	{
		this.head=null;
	}
	public void add(int data){
		node first=new node(data);
		if(this.head==null)
		head=first;
		else
		{
		node temp;
		for(temp=this.head;temp.ptr!=null;temp=temp.ptr);
		temp.ptr=first;
		}
}
	public void print(){

		for(node first=this.head;first!=null;first=first.ptr){
		System.out.println(first.info);
		}


}
	public void deleteNode(int n) {

		if(head ==null){
		System.out.println("List is Empty");//Checks if Empty
		}
		if(head.info == n){
		head=head.ptr;
		}
		if(head == null){ // Check if there was only one element in list
		return;
		}
		node curr = head;
		while (curr.ptr != null) {
		if (curr.ptr.info == n) {
		curr.ptr= curr.ptr.ptr;
		} else {
		curr = curr.ptr;
		}
		}
	}
		public void delpos(int position)
	 {
			 // If linked list is empty
			 if (head == null)
					 return;
			 node temp = head;

			 // If head needs to be removed
			 if (position == 0)
			 {
					 head = temp.ptr;   // Change head
					 return;
			 }

			 // Find previous node of the node to be deleted
			 for (int i=0; temp!=null && i<position-1; i++)
					 temp = temp.ptr;

			 // If position is more than number of ndoes
			 if (temp == null || temp.ptr == null)
					 return;


			 node ptr = temp.ptr.ptr;

			 temp.ptr = ptr;  // Unlink the deleted node from list
	 }


public static void main(String[] args){
	Linkedlist l = new Linkedlist();
	Scanner s = new Scanner(System.in);
	int n,p,c,e;
	int ch=1;
	while(ch==1)
	{
	System.out.println("Enter your choice 1:Insert 2:Delete a particular element 3:Print 4:Delete a particular position");
	c=s.nextInt();
	switch(c)
	{
	case 1:System.out.println("Enter the no:of elements to be inserted");
	       n=s.nextInt();
	         System.out.println("Enter the elements to be inserted");
	          for(int i=0;i<n;i++)
	            {p=s.nextInt();
	             l.add(p);
	             }
	          break;
	case 2:   System.out.println("Enter the element to be deleted");
              int re=s.nextInt();
              l.deleteNode(re);
              break;

	case 3:   System.out.println("The elements of linked list are:");
	          l.print();
            break;
	case 4:   System.out.println("Enter the Position");
	          e=s.nextInt();
	          l.delpos(e);


	}
	System.out.println("Do yo want to continue Y=1 and N=0");
	 ch=s.nextInt();

	}
    s.close();
}
}