Stack Runner

Stack.js

/*
Last in, first out linked list.
Stack
  - top
  + push
  + pop
  + peek
  + getLength
  + isEmpty
*/

function Stack() {
  this.top = null;
}

Stack.prototype.push = function(n) {
  n.setNextNode(this.top);
  this.top = n;
}

Stack.prototype.pop = function() {
  if(this.top != null) {
    var n = this.top;
    this.top = n.getNextNode();
    return n;
  }
}

Stack.prototype.peek = function() {
  return this.top;
}

Stack.prototype.getLength = function() {
  var n = this.top;
  var len = 0;
  while(n != null) { // Thanks to Gianluca for recommending that I change to this from if-else.
    n = n.getNextNode();
    len++;
  }
  return len;
}

Stack.prototype.isEmpty = function() {
  return (this.top == null); // Better than a conditional, right?
}

#36: Nice implementation -- and thank you for citing your "source"!
#44: Beautiful!