Code snippets in interview

Spotting and fixing errors is obviously an important part of a developer day-to-day, but shouldn't be used alone for the purpose of technical evaluation.

Fixing errors (or bugs) can be hard and tricky, but we can split them in 2 main types:

1. Compile time
2. Runtime

If you have a solid understanding of the language in question, you should be able to quickly figure out most of the compile time errors, mainly in a small snippet.

Runtime errors are generally trickier, but in C you should be able to spot a simple index out of bound, a NULL (or dangling) pointer dereference, double frees, infinite loops, wrong conditionals, and so on. Of course, here we're not talking about gigantic complex code. Even though snippets can be extremely complex, I don't expect it in a interview. Mostly because I would reject any employer that prefers small-complex over simple-readable code (except when it comes to performance).

The best way to get better is practicing. I learn something nearly every day at StackOverflow, and I think the time I invested here has been reciprocated. As an example, I recently started querying the standard because it's cited so many times in questions & answers that it became impossible to get involved in some discussions without a solid reference to back me up.

To conclude, I seriously doubt this "interview method" is effective, unless the employer looks for someone to fix bugs exclusively. Otherwise, restricting the technical evaluation to such test means the employer is ignoring more important skills.

Yes, but not completely.

You should judge a candidate on technical merits, but not solely. Having them write code (or use code) during the interview is essential in my opinion, but at the same time you need to look at much more then that. Are they a good fit for the team? Do they have the experience necessary to work without instruction? Do they interact well with others?

do not discount these type of interview questions. the skill being tested in 'code comprehension' questions is the ability to do a mental dry run of the code. this skill demonstrates greater feel for the language. candidates who possess this ability will write code that works the first time, and will be able to do it faster. they will also be able to copy paste code from other projects and modify it faster.

the way to improve this skill is to read more code and try to understand what it does.

you can start with the smaller open source c libraries.

another way to improve this ability is to solve computer programming problems in at least 5 different ways.

yet another way is to ensure your code is correct before compiling and executing. to make sure you are doing all the work, either you use a simple text editor, or you turn off all the syntax highlighting/intellisense stuff while you are programming.