Fizzbuzz is useless as an interview question

Don't use FizzBuzz to filter out bad senior developers.
May 12 2012

…Almost.  There’s a few places on the web that mention the FizzBuzz problem as a good problem to weed out useless applications for senior developer positions, citing that over 30% of university graduates can’t do this in 10 to 15 minutes.  Seriously?  What shoddy uni do they go to.  Admittedly I’m not a graduate, but all the concepts needed to implement this in no time flat are taught in first year uni!

What’s the FizzBuzz problem? The problem goes like this: print out all the integers from 1 to 100, replacing every integer divisible by 3 with the word “Fizz”.  Also replace every integer divisible by 5 with the word “Buzz”.  If an integer is divisible by 3 and 5 replace it with FizzBuzz.

The module operator is the key to the solution.  If a number is wholly divisible by another, it’s modulo is 0.  EG 20 module 5 is 0 because 5 goes into 20 exactly 4 times.

Without further ado, here’s my 30 second solution.

for (int i = 1; i <= 100; i++)
    if (i % 3 == 0 && i % 5 == 0)
    else if (i % 3 == 0)
    else if (i % 5 == 0)

See what I mean? Trivial isn’t it.  FizzBuzz is ok to give people with less than 1 year experience, just to show they can cut at least some code, but it’s not at all representative of tasks a senior developer would perform.

What does a senior developer typically do?

  • Write test plans
  • Gather requirements
  • Lead and mentor teams
  • Determine architectures
  • Cut code

A senior developer should at least be quizzed on patterns.  I recently applied to two respectable software development companies for a senior develop position.  Both required me to complete a small task prior to them even looking at my resume.  This included writing test plans, and providing production ready code for a trivial application, but one that was complex enough to show knowledge and flair for development.  E.G. the use of patterns, a layered architecture, use of S.O.L.I.D. principles, TDD or DDD or whatever takes your fancy.  I think this approach is much more suitable for getting quality employees.

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