Monday, July 14, 2014

Naughty Beginnings

Attached is the beginnings of a game that we plan to use to test a new AI being.  This is not the most stringent test, in fact it is a children's game.  At this point, I began coding the solution, but have to run to the lab to put out a fire that the AI being started while throwing a tantrum (and a few technicians).

Get the gist:

Please complete the HumanObserver.display method for a command-line interface (CLI) or HTML interface.

Please don't get distracted by the remaining classes in the overall design.  I was simply blocking out the design ahead.  Once we have the display, I expect the project will iterate rather rapidly.

Thank you.  I look forward to seeing some naughts, crosses, and elegant code.

Background: This is a Ruby adaptation of a interview question that was so popular in the hiring of C programmers that I believe it to be influential in the making of the movie "War Games".

Tuesday, July 8, 2014

Wishing you great success

Given the following definitions of success:
1. the favorable or prosperous termination of attempts or endeavors
2. the attainment of wealth, position, or honors
3. a performance or achievement that is marked by success
4. a person or thing that has had success
5. the difference between realized and expected value
6. the correct or desired result of an attempt
7. the opposite of failure
8. going from failure to failure without loss of enthusiasm
9. the result of a desire for success being greater than the fear of failure
10. the result of rising early, working hard, and striking oil

A. Which is nearest to your definition?

B. Which is the nearest to your ideal boss?

C. Which is the nearest to your ideal colleague?

D. Which is the nearest to your ideal dependency?

E. Which is the nearest to that which you would wish upon your child?

F. What type of person would you attribute to each?  For example, given a definition of "success is the cause of more work" could be attributed to a dependable worker.

Wednesday, October 9, 2013

QA Automation a la Westinghouse

No single technological advance meant more for a maturing railroad industry than the invention of the air brake….

This like the story of the invention of the computer programming language C++ are occasions where automation not only made a hugely significant impact, but also they are stories that are relatively open, providing great insight into the minds of great automators.

George Westinghouse, like Nikola Tesla (who Westinghouse employed), did not invent from nothing or just work hard. Where Tesla had decided upon AC as the solution upon seeing how obviously poor performant the brush-based DC solutions must be, Westinghouse decided upon an engineer-driven railroad braking system similar to how a horse-drawn carriage driver pulls the reigns, Westinghouse envisioned the engineer pulling reigns of some sort to apply brakes on every car (this couldn’t be employed with a physical connection, ie multiple levers pulling a metal shaft per car). Westinghouse’s great epiphany towards solving the problem of brakemen running on top of the cars and the scaling and (life) cost and poor stopping performance of the manual solution did not come from banging his head on a train-specific problem, his great epiphany came upon hearing news of an air-driven drill employed in Italy to excavate minerals. The simplicity of the invention in hindsight is awesome. The length of time to implement less so. The end result, though, the train industry scaled, and in the expansion was able to remove the need to have men run atop the train cars, saving lives, but more importantly to the owners increasing the number of cars at the command of the engineer who was nearest the upcoming rail obstacles.

With QA being the engineers with the clearest sight of obstacles (and opportunities since we aren’t on a rail), automation is our salvation.

Saturday, August 17, 2013

Interview Questions - Teaching, !Yet Another For Loop

Q: How would you teach loops to someone who is new to programming?
After the likely:
var loopAction =
  (i) => { Console.WriteLine("Current Value: {0}", i); };
for(var i = 0; i <= 10; i++) {
Prompt for a loop that uses a non-numerical loop-control variable.  This should give the developer the opportunity to show that they truly understand the nuts&bolts of what we do.

Friday, August 9, 2013

Interview Questions - i18n and Beyond YU

Q: While updating an  ASP.NET Commerce Starter Kit (CSK) implementation, you encounter the following:
    <asp:dropdownlist font="" id="ddlCountry" nbsp="" runat="server">
        <%/* snip - other countries, for brevity snip */%>
        <asp:listitem value="YU">Yugoslavia</asp:listitem>
Similarly, the following is in the code behind:
    public enum Country
        /* snip - other countries, for brevity snip */
        YU = 235,
What would make this okay?
If it is not okay, what would you propose to correct this?
Background: In 1991, Yugoslavia and its status as an internationally recognized country disintegrated.
The CSK implementation was originally contracted after 1991. Does this fact change the way you will approach the solution? If so, how?

Friday, June 14, 2013

Worthy as in Ladybugs

"Interesting and helpful information. If at all you are free any time, would like to understand more on AWS side."
- Contractor who is charging the company I work for $$ per hour

Programmatic access to ephemeral ~hardware resources that has been available to the public since 2004, with documentation well written and hedged by the company and community, hmm, yes, lemme spend some of my free time regurgitating enough of it to be dangerous.

There is a part in all of us, our inner blowhard, that takes pride in receiving adoration or praise for presenting knowledge whether it is our own or as in this case quite some many others' worthy product.  We see this in tech company's efforts to re-publish the web on corporate wikis (write the novel bits instead).  We see this in hallway "soapbox" sessions.  There is no denying the satisfaction that comes from people listening (and earnestly) to you.

But free?!  Which free is intended here?  Afaic the exchange of 3rd person knowledge is neither free as in beer nor free as in speech.  Re-representing a non-novel concept in a manner that lifts those from the inability to seek and acquire information for themselves is quite costly.

But there is a place for such a thing and it lies in the distinction between a similar juxtaposition.  The exchange of knowledge should not be "Worthy as in Snickers", but "Worthy as in ladybugs".

Snickers satisfies.  If you don't like chocolate, peanuts, nougat, mouth watering caramel, and the care that goes into making this product, substitute Snickers with a product that is made with quality ingredients and is the labor of a skilled team of artisans, but available to the masses, substitute hand-crafted ale.

Ladybugs are beneficial.  If you are squeamish about "bugs", and who in software isn't (I minored in Entomology, so not I :D ), so can't appreciate the self-propagating, aphid-eating, beauties which are the "gateway insect" for so many children who grow to have a healthy relationship with their natural world, okay, substitute yeast.

In the exchange of pure information, no working product involved, worthy as in ladybugs should apparently stand out as the winner of meeting the "free" price tag.  So when should I give freely my ladybugs?  Afaic when they are going to a good garden, one that may be overrun in one corner with aphids, but not to one which has a gardener that allowed the whole garden to be overrun nor one who refuses to devote time, experiment, read the literature, well one who is clearly not a gardener, and surely to one who is worthy, one who will be ladybugging another gardener :)

Thursday, January 31, 2013

IEnumerable Still Misunderstood

With .NET 4.5 released, adopted, and leaking Task all over the code, it shocked me enough to write about a recent set of interviews in which I found that IEnumerable, the basis for .NET 3.5's biggest feature LINQ, is still misunderstood.  Three out of three recent contract candidates equate IEnumerable with List and when pressed fail over to "Well, then Collection."  If you fail to understand what is wrong with this belief, read on.

The interview question that consistently is bringing out the wrong belief that IEnumerable is a data structure follows:
We are building a distributed counter system and to reduce client messages the system receives messages such as "INC 10 /exceptions/nullReferenceExceptions" which will INCrement by 10 the counters for "exceptions" and "nullReferenceExceptions".  Don't worry about the overall implementation, we just need the bit where the counter "path" is multiplexed (if needed: meaning that a single message turns into multiple messages).  How would you code the method to extract the parts of the path?  Let me start by providing the method signature:
string[] ExtractPathParts(string path);

The answers besides highlighting whether the candidate prefers for or foreach, the answer also highlights whether the candidate understands IEnumerable and is willing to argue to change the method signature.  Unfortunately, even with prompting, the candidates are failing to understand (yes, this could be due to selection bias :/ ).

So what is IEnumerable?  IEnumerable is far from a data structure; it is an adapter for data structures or code to appear like a data structure.  The latter was more the reason for the development of LINQ and its core bit, IEnumerable.  This was the most significant early push in .NET Framework development, bringing functional programming more to the fore.
The following is an example where code, not an existing data structure, uses IEnumerable to act like a data structure:

public IEnumerable ExtractPathParts(string path)
  if (!string.IsNullOrEmpty(path))
    const char slash = '/';
    const char whack = '\\';

    var startIndex = 0;
    var pathLength = path.Length;
    var ch = default(char);
    for(var i = 0; i < pathLength; ++i)
      ch = path[i];
            if (ch == slash || ch == whack)
        var subLength = i - startIndex - 1; //<< -1 to omit the slash
        if (subLength > 0) //<< this also omits the leading slash
          if (startIndex > 0)
          ch = path[startIndex];
          if (ch == slash || ch == whack)
          yield return path.Substring(startIndex, subLength);
        startIndex = i;

    ch = path[startIndex];
    if (ch != slash && ch != whack)
      yield return path.Substring(startIndex);

The above while not being DRY, it is focused on yield return and this being the important bit in understanding IEnumerable and its importance in LINQ.  An alternative implementation follows:

public string[] ExtractPathParts(string path)
  if (string.IsNullOrEmpty(path)) return new string[] {};
  return path.Split('/', '\\').Where(it => !string.IsNullOrEmpty(it)).ToArray();

The above uses LINQ, but is missing the point.  LINQ was developed to allow developers to reduce memory allocations, trading CPU which is overly available with the increase in processors per commodity server and per consumer desktop machine.  Memory costs physically are not bounding consumers or systems engineers.  64-bit processors are making memory more addressable, so more available.  These are not the reason why memory allocations should be avoided where possible.  The reason to avoid memory allocations is that .NET, like other garbage collection based memory management models, suffer a blocking point when garbage collection occurs.

I hope that this article helps to make .NET Framework 3.5 understood more broadly.  If not, please pose questions.