Job Interview : switch(char) again! Twenty years on!

I've spoken about some of the strange interviews I've enjoyed over the years; notable engineering highlights were having test driven development spooned to me, when I simply didn't know the particular syntax they were demanding, or having StringBuilder suggested for a C# task where they actually needed to cross-core thread their problem, or pointing out that the CI solution being described would lead to an alien environment of folks being paralysed by fear of red flags; only to witness their development floor being paralysed by exactly those issues as I walked out the door.

Today however, I'm going to go way back and talk about one of the very early development interviews I had; this maybe like the third interview I ever had after graduating, it was with a rail rolling stock company, in a very bright and sunny room with three guys who seemed to know their entire universe was correct and they'd take no new information into their sphere of understanding.

I share this one as a friend of mine was in touch over the weekend, he had an interview, and strangely he had the exact same conversation I had... THE EXACT CONVERSATION, twenty something years later.

Let us start by sharing some perfectly valid C++ code:

bool validate(const char& value)
{
switch (value)
{
case 0: return true;
case 'x': return true;
default: return false;
}
return false;
}
int main()
{
const bool isValidOne{ validate('a') };
const bool isValidTwo{ validate('x') };
const bool isValidMe{ validate(12) };
}

Read this code, we should see an output (if we output the bools) of "false", "true" and "false"... I think we can all agree.  This is perfectly valid C++.

It isn't very clean nor pretty, we're relying on the compiler standard decaying char to int and vice versa; which is not very nice and I wish compilers would complain here, that we're comparing int to char in the first case and we're converting the integer 12 to char, I think it should really strong type this.

But that is not the point, the point is that both in my friends case and mine all those years ago the interviewers got really uppity about that "switch" statement.  They insisted that you can not "switch" on a character type...

Just flat insisted.

I remember in my experience they had me write up what they wanted on a blackboard, with chalk, and they wanted me to go through the code line by line; I wrote more or less the above, they insisted they had a character not a byte (uint8_t: though there was no standard for this at the time) and then they went off on this tangent amongst themselves about the value of the if-elseif-else stanza's they insisted would work over my solution above.

Now I was talking to these guys in the early 00's, my friend however was talking to them in 2023.  He jumped on this with the point of "well if the character is known at compile time, yes then constexpr maybe of use" and he showed them:

if constexpr(foo) and if consteval(bar) examples.

He described their faces screwing up and two of the chaps he was talking to staring at each other before making subtle notes on their paper.

It was very clear at this point that the CTO performing the interview was not keeping his knowledge up to date, the group seemed to cluster onto the idea of just maintaining what they have, stagnation like this in our joint experience can be problematic.  Both team morale and high turn over of engineers always happens when things stagnate.

I have to say in my interview I actually sat it out from beginning to end and just knew I was not interested in the role; and I did not hear from them again.

My friend however, he was genuinely concerned he'd done a good interview and they'd be offering him a role, they kept him talking for over an hour and a half!

He's a late 40's engineer of 25+ years experience, just like me; the three chaps interviewing him, including the CTO, were ten or more years his junior, it seemed they were looking to back up their team with an older head to lend legitimacy to things; and they had lost two original engineers of their project to literal retirement without replacing them.

He saw the issues and he thanked them for his time and left, with a negative to whether he would be interested in going further.  This stunned them.

It has to be said, so many interviewers forget that though they are interviewing you, you are also interviewing them like most all human interaction it is a two way street and it's crucially important to remember that in a job interview.  We spent a significant amount of our time at work, if you are not comfortable there or feel you are going to be acting out a role instead of filling one and making it your own.

I hate FizzBuzz and Will Analyse anyone who uses it

One FizzBuzz Interview so far.... News flash... The moment I am asked to write FizzBuzz during a technical test I intentionally stop and ask the questions from there on out.  I've done this a couple of times.  And you know what I learned... I learned a whole lot more about the interviewer and their processed than they found out about me.

Let me take you back to a technical interview I had about five years ago.

I drive up to the building, it is way out in the sticks; just about still in my home county, but so obscure it's in a part I have never ever been in.

I pull up and the building is like a box of black glass, no character, no soul, just a box.  The non-native tree species planted around it to discourage birds actually using the tree's and the austere grass puts me off.

Things don't get any better, for I walk through the door and there's no secretary, no desk, nothing... The lights aren't even on; this doesn't bode well.  I look around for a buzzer, a phone even a limp notice of what to do.  When a door opens and a man approaches offering me a hand to shake.  He leads me to a similarly deserted corridor with a chair in it and I'm left to my devices once again.

I read some inane notice about some award some member of the staff had received (this is important later in the interview) and I read the fire evacuation notice.  It's quiet, quiet and silent.  There's one door nearby with a few people within and another which is a closed office piled with stacks of desks..... Empty corridors - which would be dev spaces, massive rooms with a few people in them, no secretary and piles of desks?  What have I walked into?

About ten minutes later I'm ushered into this room, I've brought my CV a few piece of detail about me and some references to my technical projects at home; as well as references to some of the discussions I have on these very pages and my github.  You know actual technical things, which you can see me achieving.

I can't talk about my current work with them... Heck I can't talk to you guys about my work now.  But I do it, and I pay a mortgage; that's all the proof I can proffer.

Anyway, I seat myself and a lady explains their technical lead will come and perform the technical test, he enters a moment later with a massively overpowered gaming laptop.  I hate gaming laptops.

I much prefer a simple sleak laptop, a decent screen, nice keyboard and plenty of battery life; and I do my work on a remote machine via SSH or whatever machinations you wish.  I do not generally work on my laptop, it's a portal onto other more powerful machines which are tethered, and this way I can go take my laptop with me anywhere and get amazing performance from it, as I'm only interested in a bit of internet, RAM and then remoting into other services.

Anyway, he plonks this behemoth down and proceeds to tell me about test driven development... TDD.

I HATE TDD.

Now, I know test have a place, heck I really like doctest, including tests into code you've written, to ensure it is within specification is perfect, and validates your progress.

My hatred comes from writing tests up front, I find this backwards logic, and I don't think you could ever persuade me otherwise.  Define the scope of your input, validate it in your code (I often assert up front when data is unexpected or malformed, or at the very least bail early) and then you run your code, and then TEST the result.  I do not believe you should write a test and then further write the code to fulfill that test.

You will miss something, you will be thinking about the test as the solution, rather than the solution itself.

If anything writing the test and then producing the code to meet that test may very well be called TDD today, but when I was a lad it was called Prototyping.  And though I'm sure we can all agree prototyping is best done in a language different to your final product, it is not really prototyping when you are not producing the product, you're producing a test.

I find it wasteful of time, and often ignores enough scope, for instance I've seen a fair few hundred thousand up front tests written and then the code to meet them in my time, never have I seen a validation of the input data, the input has generally been hard set into the test.  That's not as wise a test-scope of ensuring the result after the fact.

(This does not mean test suits after the fact are the best, I just think they're the best for my style; not least as they are opt-in, for those times you are in a swing, and easy to add later).

So, TDD... Why is he telling me about TDD?

He does, he explains they have a method and that method is structured, he does not offer me any test framework specifically, instead he opens notepad and asked me to write FizzBuzz.

And the interview stops there; I don't think the guy realised it, but I stopped being interviewed at that point, I was not going to accept their job even if offered, but I wanted to see where this lad (and he was young) was going with his thinking.

This half empty hulking building and they're trying to hire engineers, and he is going on about TDD but FizzBuzz?

So I play total dumb, I simply start to write "int main"... And he surprises me.

"No No, start with the test".

Ohkakkkakay....

I have NO idea what test suites he has installed, I don't use G-Test or Boost-Test, I use doctest.  So I write a SCENARIO; he blinks and just takes the laptop off of me and starts to open some other window... I didn't know he would allow me to open some other window, this isn't my machine, I don't know what he has installed.

This sort of sums up TDD to me, the tools aren't easily defined.

Anyway, twenty minutes later and I just about have it Buzzing on 5's and I'm not very interested, I've come to a conclusion.

He isn't impressed; rightly so, but he has no idea he's just been investigated by an older and more cynical mind than his.

He leaves and no less than three people come into continue the conversation, and boy do they, they talk to me for a solid 120 minutes; I timed it... I was so bored.  But I engaged a little when they talked about their award winning technology.

I recall the poster for the lady who had won this award and mention her, by name.

"What, how do you, who has been talking to you?"

This is very strange, "no" I assure them "no-one, I saw the poster on the notice board".  One of the two girls flanking the chap in the middle here makes a note.

They talk to me about the company a bit more, they talk about their re-shuffling engineering and wanting to press their position forward to a virtual machine the customer hosts on hardware; previously they had been providing a dedicated box.

I'm terminally not interested in this boring black blocky building which now perfectly reflects the boring blocky people inside.

And I give up, I lean forward, elbows on the table, and I gather the copies of my CV from the hands of the three people and I say:

"Look, I've spoken with your technical lead, and I'm scared to my core of your processes, I don't like what I've heard, it seems you're struggling to recruit and there are reasons for this you will have to identify yourselves; I don't think I can help you"

They are scowling a little here, I'm sure they're far more used to candidates who want the job.

"Indeed, I think somewhere you have a beige room with ranks of screens and engineers in stuff suits not talking with a great board or wiki with all the failing builds traffic lit from your little test driven development board...."

At this point the lady on the left looks at the guy in the middle, who has a little switch to his eye.

"And such a stifling, control freak, desperate development environment is not one I wish to be part of"

They thank me, and I thank them sincerely.  And I leave.

As I come out of the building the sun has come around, the black glass face of the building is now not so black, instead I can see inside, there are three long benches of PC's all facing a pair of chaps at the front sporting bluetooth ear phones in one ear.  Above their heads is a large TV screen with a list of running continuous integration tasks and each has a traffic light.  As I watch one goes red, one of the two larger men touches the headset at his ear and an engineer on one of the benches glances up and starts to scrabble about on their machine.

It is a sweat shop.  I was not only right, but so happy I'm driving off.

I felt like going and knocking on the glass and cooing at them "Come, follow me, be free, be free".

But instead I just drove home.

Prior me: Just coming into edit this before it goes live on Friday, guess what I'm watching... 

And I disagree with the approach of analysing FizzBuzz; analyse the interviewer.

Development Job : Interview Questions?

I was asked a question a few hours ago, "how would you kill a named process"... This annoyed me on two levels, firstly, as I was put on the spot, but secondly I had already blogged about this exact problem just a few weeks ago...

The quiz master knew this, or rather they should have, given all the information they had about me, including this blog... So to ask tells me more about them, than my answering would tell them about me.

It tells me that they're working to a bare minimum investigative level, they're looking perhaps too much to their goal (which it to get answers they like) rather than checking anything produced before.

This would be a little like asking Sir John Geilgud, whilst interviewing for a country play.... "Have you done any acting?"

It frustrates me.

Development : No Great Shakes at SQL

I was just handed a technical test, this was for a job interview, and I was a little... well I'll say surprised, but then shocked, by the reply, lets take a look...

I was handed these SQL statements, in several questions, and then told to summarise what I should see on any output of the various instructions....

create table customers (id INTEGER PRIMARY KEY, name Text, age INTEGER, weight REAL);

insert into customers values(73, "Brian", 42, 33);

insert into customers values(1, "Helen", 12, 12.5);

select * from customers;

SELECT name, CASE WHEN age > 18 THEN "adult" ELSE "minor" END "type" FROM customers;

create table orders (id INTEGER PRIMARY KEY, customer_id INTEGER, desc TEXT);

insert into orders values (0, 73, "Apples");

insert into orders values (1, 73, "Oranges");

insert into orders values (2, 1, "Bananas");

select * from orders;

SELECT customers.name, orders.desc FROM customers JOIN orders ON customers.id = orders.customer_id;

I drew up the two tables, their info, the results of the selects and the listing of each order by the last point.

The final question was then, "alter the final query so that only orders by customers named "Brian" are displayed.

My answer was this:

SELECT customers.name, orders.desc FROM customers JOIN orders ON customers.id = orders.customer_id where customers.id = (select id from customers where name = "Brian");

Now, I'm no great shakes at SQL, it's a tool to be used, not a mantra to adhere to, so I understood that I could also solve this problem thus:

SELECT customers.name, orders.desc FROM customers JOIN orders ON customers.id = orders.customer_id where customers.name = "Brian";

Both are valid results, and yes I admit mine results in another query (within the parenthesis) however, in my mind I wanted all parameters directly in a query to be the result of other queries, meaning I could place "Select customers where name is 'Brian'" into a function elsewhere for ease of maintenance, rather than have "Brian" hard coded into the query here.

I discussed this when myself and the technical reviewer went over my suggested solution, I explained "The query in the bracket should be stand along, either as a separate query or stored procedure".

He made a note on his clip board, and I thought nothing more about it.

Fast forward a fortnight, and this morning I heard back from this job, they said I was a very good candidate, but failed the technical test on one key point.  I looked at my notes, nothing looked that key.

I left it there, and went back to the recruiter but asked them for specific technical feedback.

The feedback I received, just an hour ago...

"Over thinks the solution to a problem" and they cited the above answer.

I am flabbergasted, it seems people really would rather my not give a valid answer, or perhaps don't want to discuss the decisions I passed through in order to reach my conclusion.

Either way, I think my solution is valid, my point about being able to move the latter query into its own location is valid, code maintenance is important to me, so being able to break down none-nonsensical ordering things like SQL statements is high on my radar, but to be told I am essentially "too verbose"... I'll be frank, it's pissed me off.

But hey, what do I know?... I'm no great shakes at SQL.

Not a post for the Vicker to read - Strange Job Interviews

I was just watching this...

And it reminded me of perhaps the most awkward moment I've ever had in a job interview.

The interview was down in Cambridge, for a programming job, in an office about 700 yards from the Imperial War Museum Duxford... Which, to be honest, was the main draw for me.

Anyway, I remember being led up four flights of stairs, and into an attic room, where the walls were freshly plastered, this was a young, new company, there was a long table and I was sat at one end and then five guys came in.  Four took seats with note pads and stared at me whilst one chap stood by a flip chart of paper.

No-one said a word to me, I stood to shake hands, but they didn't come near, neither did they say a word, they were all very pale pasty looking geeks.  Now, I am also a geek, but back then I was freshly graduated, I had a romping sex life and I had the remnants of training hard at karate on me, so I didn't look too bad with a big mop of hair and a clean crisp suit on I was the anti-pole of these scraggly guys.

They all spoke with posher then you, style Cambridge accents, and they all held their nose when they realised I was a graduate from an ex-polytechnic...

But still they didn't say a word to me...

Next thing, the interview began... they asked me lots of maths like questions, then about my knowledge of internet payment systems - which at that time - before even PayPal was sod all.

And then whilst the chap by the flip chart started to draw something, one of them around the table suddenly asked...

"How do you stand about anal sex?  Either male on female, or male to male"

Stunned I just opened my mouth and closed it again... Was this an invitation?  Did they look so pasty as they didn't leave the office, I'd not seen a woman in the entire place so I was a little disturbed and didn't want to be cock-blocking or volunteering to sausage jockey any of this lot.. not for a job.

"I'm sorry?"

And another spoke...

"You know, fisting, BSDM, real hard core"

There was absolutely no anchor for my brain on this, it was not mentioned in the job description, I had nothing to go on...

"Well, I've been around"

Was my only reply...

"No, not you, videos, pictures that sort of thing?"

Pictures, I had the most gorgeous girlfriend at the time whom I could get to drop suck and swallow she was so horny... so I was not up on the old lads mag end of the market.

Then it clicked, their work, their business was porn, it was internet porn... They looked so pasty as they made their money being online pretending to be the female to male chatters online and charging for it whilst videos played.  And I was being hired because I had a few modules listed on my CV of Artificial Intelligence and Natural Language processing (my favourite module truth be told).

They wanted me to write a chat box, but their approach, the advert, their pay all turned me off the whole thing, they themselves made it all so seedy.

Perhaps there was money in it, I think the legality of the hardcore stuff they were talking about in Britain - at that time - was questionable, and so they did host their services overseas, so the job security was tenuous at best.

I never chased up the company, they no longer exist, and I didn't take the job, but I'd have liked to know how much money - if any - they raked out the masturbatory habits of the world.