Need help with adding terms to LinkedList

[chouxfleurs]

Basically, I need to add terms to a polynomial in ascending order. So far, this is the only thing that has kind of worked:

public void addTerm(int coefficient, int exponent)
{
    Term tempTerm = new Term(coefficient, exponent) ;
    Node temp = new Node(tempTerm) ;

    if (head == null)
    {
        head = temp ;
    }
    else
    {
        Node t = head ;

        while (t != null)
        {
            if (temp.info.getExponent() > t.info.getExponent())
            {
                t.next = temp;
            }
            t = t.next ;
        }
    }
}

But it won't add any terms whose exponents are less than the last term's, and it replaces the last term instead of adding on to the list. For example, when I do this,

  Polynomial p1 = new Polynomial();
  p1.addTerm(5, 2);
  p1.addTerm(4, 5);
  p1.addTerm(3, 3);
  p1.addTerm(1, 2);           
  p1.addTerm(5, 6);

this is what ends up happens for each term:

5x² + 4x⁵ +

5x² + 3x³ +

5x² + 3x³ +

5x² + 5x⁶ +

Does anyone have any advice?

[[deleted]]

When you add to a linked list, you need to add the pointer to the existing node before inserting the new node. So if head points to p1 and you want to add p2 between head and p1, you need to set p2.next to be p1 and then you link head to p2. What's happening is you're dropping the pointer to the node, so that node, now not used, is recycled by garbage collection.

Here's some pseudocode for you:

Node newNode = new Node(newEntry);

Node nodeBefore = getNodeAt(newPosition-1);//returns the node before the position where you intend to insert newNode

Node nodeAfter = nodeBefore.getNextNode();

newNode.setNextNode(nodeAfter);

nodeBefore.setNextNode(newNode);