Linked List problem, please help.

I am trying to make a method which receives the first list node of two different linked list's of ints and the method is supposed to insert the second list right before the smallest int of the first list. Here is what i have but it is very confusing and I do not know how to fix it. The other methods of the program are working fine.

Code Java:

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public static ListNode insertBeforeSmallest (ListNode headMain, ListNode headInsert)
    {
 
        ListNode start = headMain;
        ListNode prevNodeMain = headMain;
        ListNode prevNodeMain2 = headMain;
        ListNode nodePtrMain = headMain.getNext ();
        ListNode nodePtrMain2 = headMain.getNext ();
        ListNode nodePtrInsert = headInsert;
        int length = Length (prevNodeMain);
        String lowestObj = "";
        for (int j = 0 ; j < length ; j++)
        {
            if (j == 0)
            {
                lowestObj = ((String)prevNodeMain.getValue ());
                prevNodeMain = nodePtrMain;
                nodePtrMain = nodePtrMain.getNext ();
            }
            else if (((String)prevNodeMain.getValue ()).compareTo (nodePtrMain.getValue ()) < 0)
            {
                lowestObj = (String)nodePtrMain.getValue ();
                prevNodeMain = nodePtrMain;
                nodePtrMain = nodePtrMain.getNext ();
            }
            else
            {
                prevNodeMain = nodePtrMain;
                nodePtrMain = nodePtrMain.getNext ();
            }
        }
        while (nodePtrMain2 != null)
        {
            if(prevNodeMain2.getNext ().getValue ().equals (lowestObj))
 
                {
                    prevNodeMain2.getNext ().setNext (nodePtrInsert);
                    for (int i = 0 ; i < (Length (nodePtrInsert) - 1) ; i++)
                    {
                        nodePtrInsert.setNext (nodePtrInsert.getNext ());
                    }
                    nodePtrInsert.setNext (nodePtrMain2);
                    return start;
                }
            else
            {
                prevNodeMain2 = nodePtrMain2;
                nodePtrMain2 = nodePtrMain2.getNext ();
            }
        }
        return null;
 
    }

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Hey Axeander,

Just a small thing, please use

Code Java:

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code goes here

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while posting your java code.

That would make the code more readable for us.

We appreciate your co-operation. :)

Goldest

Ok thanks, but I'm cant find how to use that. Is it build into the post box, or do I need to get it from somewhere else?

Quote:

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Originally Posted by Axeander

Ok thanks, but I'm cant find how to use that. Is it build into the post box, or do I need to get it from somewhere else?

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Hi Axeander, you can get your code into the box by editing your post above and flanking the source code with either the [highlight=java][/highlight] or [code][/code], where the code goes between the bracketed tags.

Ok thanks, but do you have any suggestions about the code its self? I really need some help on it.

ListNode<Integer> start as your ListNode stores Integers.

int length = Length (prevNodeMain);

I don't see what this is for.

Usually you look at the size of the entire list, not a just a single Node.

Unless Length is another method in the class that you're not showing because you've already got it figured out.

(String)prevNodeMain.getValue ()

If you're using Integers,

prevNodeMain.getValue().toString() would be better.

I don't think the way you have it now will work.

Also, the ListNodes you're passing as parameters should have their data types. I think that you said they were both Integer.

Code java:

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public static ListNode<Integer> insertBeforeSmallest (ListNode<Integer> headMain, ListNode<Integer> headInsert)

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Yes I already have the method Length on the rest of the program which is working but for some reason when i run the program using this code,

Code java:

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 public static void main (String[] args)
    {
 
        ListNode startList, startInsert;
        System.out.println ("Entering the original list...");
        startList = getLinkedList ();
        System.out.println ("Entering the list to be inserted...");
        startInsert = getLinkedList ();
        startList = insertBeforeSmallest (startList, startInsert);
 
        // prints elements of a linked list
        ListNode tempNode = startList;
        while (tempNode != null)
        {
            System.out.println (tempNode.getValue ().toString ());
            tempNode = tempNode.getNext ();
        }
    } // main method
 
 
    public static ListNode getLinkedList ()
    { //gets linked list
        ListNode startNode, node, lastNode;
        System.out.println ("Type in a name,'none' to quit..");
        String name = Stdin.readLine ();
        if (name.equals ("none"))
            startNode = null;
        else
        {
            startNode = new ListNode (name, null);
            lastNode = startNode;
            do
            {
                System.out.println ("Type in a name, 'none' to quit.");
                name = Stdin.readLine ();
                if (!name.equals ("none"))
                {
                    node = new ListNode (name, null);
                    lastNode.setNext (node);
                    lastNode = node;
                }
            }
            while (!name.equals ("none"));
        } //else
        return startNode;
    }

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I get stuck in the while loop "while(tempNode != null)" and keeps printing the same 2 number over and over.

Ok thanks everyone, I just finished it up. Thanks for the help.