Program 1
import java.util.*;
class DoubleLinkedList
{
static class Node
{
Node ladd;
int data;
Node radd;
}
Node start=null,new1,prev1,next1,temp;
void create()
{
Scanner scan=new Scanner(System.in);
int n;
System.out.println("Enter first element");
n=scan.nextInt();
start=new Node();
start.ladd=null;
start.data=n;
start.radd=null;
temp=start;
String choice;
System.out.println("Want to continue");
choice=scan.next();
while(choice.toUpperCase().equals("Y"))
{
System.out.println("Enter next element");
n=scan.nextInt();
new1=new Node();
new1.ladd=null;
new1.data=n;
new1.radd=null;
temp.radd=new1;
new1.ladd=temp;
temp=temp.radd;
System.out.println("Want to continue");
choice=scan.next();
}
}
void display()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
temp=start;
while(temp!=null)
{
System.out.print(temp.data + " ");
temp=temp.radd;
}
}
}
void reversedisplay()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
temp=start;
while(temp.radd!=null)
{
temp=temp.radd;
}
while(temp!=null)
{
System.out.print(temp.data + " ");
temp=temp.ladd;
}
}
}
void insertFirst()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
Scanner scan=new Scanner(System.in);
int n;
System.out.println("Enter an element for insert");
n=scan.nextInt();
new1=new Node();
new1.data=n;
// new1.add=null;
new1.ladd=null;
new1.radd=null;
new1.radd=start;
start.ladd=new1;
start=new1;
}
}
void insertLast()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
Scanner scan=new Scanner(System.in);
int n;
System.out.println("Enter an element for insert");
n=scan.nextInt();
new1=new Node();
new1.data=n;
new1.ladd=null;
new1.radd=null;
temp=start;
while(temp.radd!=null)
{
temp=temp.radd;
}
temp.radd=new1;
new1.ladd=temp;
}
}
void insertMiddle()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
Scanner scan=new Scanner(System.in);
int n,pos,i;
System.out.println("Enter an element for insert");
n=scan.nextInt();
new1=new Node();
new1.data=n;
new1.ladd=null;
new1.radd=null;
System.out.println("Enter poistion for insert");
pos=scan.nextInt();
i=1;
next1=start;
while(i<pos)
{
prev1=next1;
next1=next1.radd;
i++;
}
prev1.radd=new1;
new1.ladd=prev1;
new1.radd=next1;
next1.ladd=new1;
}
}
void deleteFirst()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
temp=start;
start=start.radd;
System.out.println("Deleted node " + temp.data);
temp=null;
}
}
void deleteLast()
{
if(start==null)
System.out.println("***********List not Found*************");
else
{
temp=start;
while(temp.radd!=null)
{
temp=temp.radd;
}
prev1=temp.ladd;
prev1.radd=null;
System.out.println("Deleted node " + temp.data);
temp=null;
}
}
void deleteMiddle()
{
int i,pos;
if(start==null)
System.out.println("***********List not Found*************");
else
{
Scanner scan=new Scanner(System.in);
System.out.println("Enter poisition of node for delete");
pos=scan.nextInt();
i=1;
temp=start;
while(i<pos)
{
temp=temp.radd;
i++;
}
prev1=temp.ladd;
next1=temp.radd;
prev1.radd=next1;
next1.ladd=prev1;
System.out.println("Deleted node " + temp.data);
temp=null;
}
}
}
class TestDoubleList
{
public static void main(String args[])
{
DoubleLinkedList D=new DoubleLinkedList();
Scanner scan=new Scanner(System.in);
int ch;
do
{
System.out.println("\n-------------------Doubly Linked List-------------------");
System.out.println("1.Create");
System.out.println("2.Display");
System.out.println("3.Insert First");
System.out.println("4.Insert Middle");
System.out.println("5.Insert Last");
System.out.println("6.Delete First");
System.out.println("7.Delete Middle");
System.out.println("8.Delete Last");
System.out.println("9.Reverse Display");
System.out.println("10.Exit");
System.out.println("\n--------------------------------------------------\n");
System.out.println("Enter your choice");
ch=scan.nextInt();
switch(ch)
{
case 1:D.create();break;
case 2:D.display();break;
case 3:D.insertFirst();break;
case 4:D.insertMiddle();break;
case 5:D.insertLast();break;
case 6:D.deleteFirst();break;
case 7:D.deleteMiddle();break;
case 8:D.deleteLast();break;
case 9:D.reversedisplay();
case 10:break;
}
}while(ch!=10);
}
}
