Drowning in a C of Interviews

Drowning in a C of Interviews(blog.bitquabit.com)

54 points by rockhymas 15 years ago | 23 comments

tedunangst 15 years ago |

I really did like getting interviewed in C. :) But I was also confident using it.

It was appealing knowing that interviews were conducted in a language that wasn't really being used. Lots of companies claim they will hire smart people regardless of skills, but then you show up to interview and the guy across the table really expects you to know python and is flabbergasted that you bothered applying without it. I felt Fog Creek really demonstrated commitment to the principle by interviewing in a "useless" language. As someone with a bit of experience looking to make a change, it was a nice touch.

rockhymas 15 years ago | |

I would agree. Though C is far from useless, it really isn't used here at the Creek. Which was a double bonus for me, since after 6 years immersed in C and C++ I could find a job that let me do something new but that I felt very comfortable interviewing for. That said, I really don't believe you need lots of C experience to do well in our interviews.

My full response to Ben is at http://news.ycombinator.com/item?id=2442696.

amackera 15 years ago | |

You're pretty deluded if you think that C is a "useless" language.

tedunangst 15 years ago | | |

It more or less is at Fog Creek. I am not unfamiliar with the usage of C outside of Fog Creek.

thrawea 15 years ago |

It's a bit hard for me to believe that there are programmers, who dont understand Pointers!

Though I am still in school, I feel everyone should understand how Memory works.

My assumption is that everyone should at least know about:

1. Pointers and their physical meaning

2. Difference between Process specific virtual memory and physical memory

3. Difference between Static, Stack and Heap Memory.

4. Also it is important to understand what happens when a disk access is required, and difference between Random reads and Sequential reads.

5. Bonus if you can understand, how swapfs is utilized and L2,L3 cache work.

cygwin98 15 years ago | |

I believe there is a difference between knowing how memory and pointers work and being proficient at pointer manipulation in C.

If you enforce such kind of interviews in C, you will miss lots of great FP programmers. Maybe you don't care anyway.

pjscott 15 years ago | | |

I would bet that people who are good at working with pointers in C are drastically over-represented among great functional programmers, so you won't actually lose that many.

adestefan 15 years ago | |

It's not really that shocking. Most people don't program in a language with manual memory allocation anymore.

I would guess that people might know 1 when they think about it some, but really don't know anything about the rest.

burgerbrain 15 years ago | | |

Even if they don't personally use languages that require this knowledge on a regular basis, the idea that someone could come through a CS education and not know it is pretty stunning.

bostonpete 15 years ago |

This blog post seems to have the feel of someone interpreting scripture. Only in this case, the author of the scripture is also the one he's presumably challenging with his interpretation. I assume Joel is ultimately responsible for the existing FC approach to interviewing... (?)

jedsmith 15 years ago |

This isn't a C-specific problem; of course people are going to be more relaxed in their comfort zone. If you asked me to write a Web server in Python, I'd be a lot more relaxed about it than if you asked me to do the same in Forth. There's a reason nothing changed when he dropped C (what goes unsaid: is he putting C in the job description?).

Joel's observation about pointers is dead-on, but I've personally beat that horse on HN in the past and will spare everyone a greatest hits anthology.

tom_b 15 years ago |

Hmmmm. Given a language X that is not used in actual development in an organization, at what point does interviewing with whiteboard coding in X become just another credential?

I like (FTA): "So I’ve picked a question that forces candidates to design a data structure" . . . "I’ll continue conducting my interviews in the language of the candidate’s choice"

As an even more general question to hackers here, what would impress you more? A candidate who comes in, whiteboards out an algorithm and data structure in C to solve a problem, or a candidate solves the same problem in Clojure?

Particularly if your org uses neither of those two languages :-) Of course, you have to grok the different paradigms you might use in both languages or you'll probably be unable to make a decent judgment.

tedunangst 15 years ago | |

My tactic interviewing people for a sysadmin position was to allow them to use any language they knew. For the most part it went well. Even someone who doesn't know a thing about programming can generally pick up how the interview is going from the candidate's reactions. But occasionally someone would quite confidently assert some code would do something I didn't think it did, but I didn't really have the powershell chops to call them on it. For a sysadmin position, there was no one language we could standardize on, and the interview was designed more to test ability to use one's tools, not to program, so it was the best we could do. We weren't going to make every candidate learn perl/python/ruby just to apply.

A dev candidate who solves a problem in clojure may be impressive, but since I'm less qualified to judge, I will be less confident hiring them. Your best chance to get hired is to convince me that you are better than everyone else, and the best way to do that is to do something impressive that I can compare to everyone else.

I've also had people go from passing to failing because they overreached. More than one candidate successfully produced a correct C solution and then sunk their own battleship by volunteering a completely wrong soliloquy on heap vs stack memory. "Noone knows you're stupid until you open your mouth." Do NOT use clojure if you're betting the interviewer won't catch your mistakes.

mdwrigh2 15 years ago |

I interviewed at Fog Creek recently (and I don't think it was with Ben, the post's author), and I actually didn't code in C. I answered my questions in Python, just because I'm more comfortable with it these days. So I don't know if this is a new thing they are trying out, or if internship interviews are different.

(I believe I'm allowed to say this about the interview. If Joel or someone at Fog Creek comes across this and takes issue, just let me know and I'll remove the post.)

gecko 15 years ago | |

If you interviewed in Python for a dev position, then you interviewed with me or one other coworker who is also trying this experiment. The majority of Creekers still do their interviews in C, and are in fact passionate about it: http://thoughts.rockhymas.com/post/4580899270/in-which-i-def...

droz 15 years ago |

Really depends on your situation, but do your interviews in pseudo code. Evaluate their ability to translate your requirements into a logical set of events that will satisfy your requirements.