C#.NET Interview coding questions

dublin104 · 05-05-2014 4:56pm #1

I have an interview for a post as a C#.NET developer which will include a 'whiteboard' test where I'll be asked to code a problem/function.
Impossible to know what I'll be asked to do, what have you been asked in an interview?
Thanks

PeachPie · 05-05-2014 5:54pm

dublin104 wrote: »

I have an interview for a post as a C#.NET developer which will include a 'whiteboard' test where I'll be asked to code a problem/function.
Impossible to know what I'll be asked to do, what have you been asked in an interview?
Thanks

Fizz bang..look it up.
Thanks me later..

dublin104 · 05-05-2014 6:03pm

Fizz Buzz? Do employers really ask that?

Mo14 · 05-05-2014 7:12pm

Check out the book 'Cracking the Coding Interview' if you have the time and haven't already. I'm only a third year intern so this may not be too relevant, but for the whiteboard part of the interview for my internship, I was asked 'Given a string, write a method that returns a string containing the duplicate characters in the input string'.
So for the input "aaghgd", you'd return "ag". Very trivial, but it would still weed out the people who can't code to save their life.

c_man · 05-05-2014 7:30pm

dublin104 wrote: »

Fizz Buzz? Do employers really ask that?

Yup, unfortunately.

dublin104 · 05-05-2014 8:13pm

Mo14 wrote: »

Check out the book 'Cracking the Coding Interview' if you have the time and haven't already. I'm only a third year intern so this may not be too relevant, but for the whiteboard part of the interview for my internship, I was asked 'Given a string, write a method that returns a string containing the duplicate characters in the input string'.
So for the input "aaghgd", you'd return "ag". Very trivial, but it would still weed out the people who can't code to save their life.

Thanks, will check out that book. I have some time until the interview.

mrkite77 · 05-05-2014 11:31pm

If I were to interview someone for a C# position, I'd ask them to do some simple tasks and see if they used LINQ or not. Checking to see if people use idiomatic C# is the quickest way to see if they're C# programmers or Java programmers who quickly taught themselves C# syntax for the job.

c_man · 06-05-2014 2:24pm

Do you not think that you're narrowing your choices there? I disagree with profiling devs on the language they happen to most proficient in at the time.

I'm willing to bet that a decent Java head will find his feet in C# in no time.

BrokenArrows · 07-05-2014 10:31am

mrkite77 wrote: »

If I were to interview someone for a C# position, I'd ask them to do some simple tasks and see if they used LINQ or not. Checking to see if people use idiomatic C# is the quickest way to see if they're C# programmers or Java programmers who quickly taught themselves C# syntax for the job.

Surely the use of LINQ or not doesn't make a good or bad programmer. If you want to know if they can use LINQ then put that in the question.

I can use LINQ if I choose but whether I use it or not depends on the situation.
Personally I find LINQ makes code a lot less readable.

not1but4 · 07-05-2014 11:12am

dublin104 wrote: »

Fizz Buzz? Do employers really ask that?

Large MNC with (250,000 employees) asked me it. It was harder to pretend that I hadn't seen it before.

stevenmu · 07-05-2014 11:25am

BrokenArrows wrote: »

Surely the use of LINQ or not doesn't make a good or bad programmer. If you want to know if they can use LINQ then put that in the question.

I can use LINQ if I choose but whether I use it or not depends on the situation.
Personally I find LINQ makes code a lot less readable.

+1, there's times where LINQ provides very real benefits, but for something really easy it just makes code slightly harder to read. In an interview in particular, I'd be tempted to not use LINQ so that my thought process and workings would be very clear.

Giblet · 07-05-2014 11:37am

I usually ask one question regarding Linq, which tells me more about their knowledge that any syntax.

public static void Main(string[] args)
{
    Console.WriteLine("Before Method");
    GetStrings();
    Console.WriteLine("AfterMethod");
    Console.ReadLine();
}


public static IEnumerable<string> GetStrings()
{
    Console.WriteLine("inside method");
    yield return "1";
    yield return "2";
}

What is the output of the above.

Aswerty · 07-05-2014 12:12pm

@Giblet, That is just trying to catch people out. If you executed it and asked them why it worked that way, fine. But I'd really think less of an interviewer for asking a question like that. Understading how LINQ relies on lazy execution doesn't mean you're always going to see the execution path when shown a snippet of code. At least if you had a line to force the execution at the end of the program it would at least give the interviewee a prompt as to what the "gotcha" is.

I would have failed this question even though I have the understanding you were looking for. I also think a lot of people don't use the yield keyword much which adds an unneccessary complication to the mix.

Giblet · 07-05-2014 12:23pm

I guess I should have expanded more, I don't just throw that at the interviewee and chuckle to myself, it's broken down into what different Linq calls will do in each case.

Aswerty · 07-05-2014 12:49pm

I suppose the goodness of a question is dependent on the context it's asked in as well as to the discussion that arises out of the interviewees answer, be it right or wrong. I ran your code in LINQPad thinking you were interested in the yield keyword (while wondering why the IEnumerable wasn't used). On seeing the output I realised it was an understanding of lazy execution that was being sought.

Giblet · 07-05-2014 1:08pm

Exactly, but the more important thing is how
Where,
Take and Skip
and finally ToList
will work.
Also, I would probably ask how to implement a new Linq Method (without referencing it's an extension method)

c_man · 07-05-2014 6:21pm

not1but4 wrote: »

It was harder to pretend that I hadn't seen it before.

I actually prefer to hear that a candidate has heard of it!

C#.NET Interview coding questions

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