gistfile1.js

Stack.prototype.getLength = function() {
  if (this.top == null) {
    // If the Stack is empty, return 0
    return 0;
  } else {
    // Otherwise start at the top, and begin counting at 1
    var n = this.top;
    var len = 1;
    // Every time we call getNextNode() and get a Node object back (instead of null)...
    while (n.getNextNode() != null) {
      // increase the counter
      len++;
      // and update the value of n to progress to the next node.
      // Without this line, we would hit an infinite loop always checking if the top Node has a next node.
      n = n.getNextNode();
    }
    // Finally return the length that we've counted up to
    return len;
  }
}