Question

Since there are no self-refering pointer concept in Java… How do I proceed to tackle this issue…

I am not allowed to use Built in class of Link List in Java…

But “Should follow the same method of creation of Link List like in C.” What could be the best Substitute node->next, node->prev in Java…

Answer 1

Instead of an object with a pointer to the next node and an var, in java linked lists can be implemented by making a class with a member variable of itself.

a sample implementation is listed below:

 1    public class Node
 2  {
 3      private int myInt;
 4      private Node nextNode;
 5     
 6      public Node(int val)
 7      {
 8          myInt = val;
 9          nextNode = null;
10          return this;
11      }
12  
13      public int getMyInt()
14      {
19          return myInt;
20      }
21  
22      public Node(Node prev, int val)
23      {
24          prev.nextNode = this;
25          myInt = val;
26          nextNode = null;
27      }
28  
29      public void addNode(Node newNode)
30      {
31          nextNode = newNode;
32      }
33  
34      public void printNodes()
35      {
36          System.out.println(myInt);
37          if (nextNode != null)
38          {
39              nextNode.printNodes();
40          }
41      }
42  
43      public void printNode()
44      {
45          System.out.println(myInt);
46      }
47
48      public Node nextNode()
49      {
50          return this.nextNode;
51      }
52  }

To create a link list, create head:

Node head = new Node(1);

This node class has two ways of adding nodes to the list:

Node secondNode = new Node(head, 2);

or

head.addNode(new Node(2))

here is an example of a list with values 1 – 10

Node head = new Node(1);
Node tempPtr = head;

while ( tempPtr.getMyInt() <= 10 )
{
    tempPtr.addNode(new Node(tempPtr.getMyInt()+1));
    tempPtr = tempPtr.nextNode();
}

now you can print access the elements of this list by iterating through the list.

tempPtr = head;
while ( tempPtr != Null )
{
    tempPtr.printNode()
    tempPtr = tempPtr.nextNode()
}