It's more typical to check base case first in a recursive function.

Note that lines 12-13 and 19-20 look almost exactly the same!

The only difference is we're working with first in the starter function and x.next in the helper function.

  public void insert (double item) {  
    if (first == null || first.item >= item) {
      first = new Node (item, first);
    } else {
      insertH (first, item);
    }
  }
  private static void insertH (Node x, double item) { 
    if (x.next == null || x.next.item >= item) {
      x.next = new Node (item, x.next);
    } else {
      insertH (x.next, item);
    }
  }

Computes forwards

A single function call both:

• creates the new node
• puts it in its place