LinkedList.js

function ListNode(){ // SingleLinkedListNode
  this.element = "";
  this.nextNode = null;
}

function LinkedList () {

  var start, end;
  var n;

  this.create = function(){
    start = null;
    end = null;
    n = 0;
  };

  this.first = function(){
    return start;
  };

  this.last = function(){
    return end;
  }
  
  this.length = function(){
    return n;
  };

  this.next = function(p){
    return p.nextNode;
  }

  this.retrieve = function(p){
    return p.element;
  }
  
  // Schiebe das neue Element in einen Knoten hinter p
  this.insert = function(p, x){
    node = new ListNode();
    node.element = x;
    if(p == null){ // p = NIL, Einfügen an erster Position
      node.nextNode = start;
      start = node;
    }else{
      node.nextNode = p.nextNode;
      p.nextNode = node;
    } if(p == this.last()){
      end = node;
    }
    n = n + 1;
    return node;
  };

  // Hilfsfunktion um den Vorgänger von p zu finden
  // null falls p == start
  this.predecessor = function(p) {
      // finde Vorgänger von p
      currentNode = start;
      while(currentNode) {
          if(currentNode.nextNode == p)
              break;
          currentNode = next(currentNode);
      }
      return currentNode;
  }

  this.delete = function(p)
  {
    pred = p.prevNode;
    if(pred) {
      pred.nextNode = p.nextNode;
    } else {
      start = p.nextNode;
    }
    if(p.nextNode != null){
      p.nextNode.prevNode = pred;
    } else {
      end = pred;
    }
    n = n - 1;
  };
}