Re: Interview Questions

From:

"AliR $VC++ MVP$" <AliR@online.nospam>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 16 Apr 2009 14:56:43 -0500

Message-ID:

<Y4MFl.29222$ZP4.27850@nlpi067.nbdc.sbc.com>

That's a good idea. But since I don't write buggy code, it will be hard. ;)

AliR.

"Joseph M. Newcomer" <newcomer@flounder.com> wrote in message
news:hlveu4lk8nu651btrpgdd2kt9dvu0pc0vk@4ax.com...

Then if your goal is to check for understanding of virtual methods, then
indeed the
questions are valid.
joe
On Thu, 16 Apr 2009 09:44:04 -0500, "AliR $VC++ MVP$"
<AliR@online.nospam> wrote:

Hi Joe,

The emphasis on virtual functions is that I want to make sure they have a
good understanding of OOP. If they don't then I might end up redesigning
alot of their classes. But I guess you are right in a way that they don't
need to know this stuff to write programs but OO is major part of
programming in C++ or C#.

If they are reading this newsgroup, then that is a good thing. Then they
are
using this as a tool to learn. (I just posted questions, and not the
answers). You will be surprised that the fact that I emailed these
questions
to people how applied and alot of them didn't get the answers right, these
are questions that can be easily googled, and the answer is within the
first
2 or 3 links.

Any ideas on questions to gauge a person's problem solving skills?

*****
Hand them a program with a bug in it and watch how they look for it.

I am truly amazed at the differences between how someone at our level
looks for bugs and
how beginners look for bugs. They are neither efficient nor effective.

I've related the story here several times of my looking for a bug and
finding in seconds
what freshmen took 5-10 minutes to find (typically about 7 minutes). The
bug was trivial,
you could spot it, a glaring error, in less than 30 seconds with the
description given.

Don't use problems of the "PC-Lint what's wrong with this program?" style
(the example you
gave is actually very good in this respect). Pick less subtle problems.
Ask them to talk
out loud about how they are approaching the problem. I solved your
problem in under 30
seconds. But you would learn a lot from an interviewee by listening to
them reason.

Ultimately, the only way to spot good problem solvers is give them
problems to solve. And
please, not the "reverse a string" or "reverse a list" problems; they
don't really reveal
problem *solving* ability.
joe
*****

AliR.

"Joseph M. Newcomer" <newcomer@flounder.com> wrote in message
news:8rmcu4h9jsc374avmf4vfttm75mr0itcng@4ax.com...

See below...
On Wed, 15 Apr 2009 16:33:56 -0500, "AliR $VC++ MVP$"
<AliR@online.nospam> wrote:

Do you guys remember the "MFC interview questions" post a few weeks ago?

Well, I'm trying to hire a Jr. programmer to do some C#/Silverlight work
and
also help out with the C++/MFC stuff. Therefore OOP understanding is the
most important part for me. (The rest can be taught)

What do you guys think of these questions? Can you think of some good
questions to judge a persons problem solving skills?

1. What is polymorphism?

2. What is a virtual function, and how is it used?

****
This may be a stretch. While I consider this an important piece of
knowledge, I find that
many programmers can program effectively without it, as long as they
don't
take on
anything with abstract superclasses.
****

3. What is a pure virtual function, and why would you use it?

****
Diito. Good concept, but is it critical for a junior programmer?
****

4. When and why would you want to have a virtual destructor?

****
This is three virtual questions in a row, and that may be overkill. If
they miss question
2, they have no hope of answering 3 and 4. If they can answer 2, 3 and
4
are probably
redundant.
****

5. What is the difference between a pointer and a reference? (In
other words: What must you always do to a reference?)

****
I'm not convinced this is a critical question. I prefer to use
references
whenever
possible, and I think Microsoft overuses pointers when references would
be
a better
choice.
****

6. What's wrong with the following code sample?

class Sub

{

};

class Super1: public Sub

{

};

class Super2 : public Sub

{

};

class DoesSomething

{

public:

     void DoSomething(Super1 *pSuper)

     {

     }

     void DoSomething(Super2 *pSuper)

     {

     }

};

void main()

{

     std::vector<Sub *> SubVector;

     SubVector.push_back(new Super1);

     SubVector.push_back(new Super2);

     std::vector<Sub *>::iterator cur = SubVector.begin();

     DoesSomething Something;

     while (cur != SubVector.end())

     {

           Something.DoSomething(*cur);

           delete *cur;

     }

}

How would you solve this problem?

****
It seems pretty obvious. There's at least three issues I see wrong in
that function call
preceding the delete, but are you sure the applicants are not reading
this
newsgroup?
Questions 2 and 3 are critical to answering it, but this involves,
again,
knowing how to
answer 2 & 3.

Thanks

AliR.

Joseph M. Newcomer [MVP]
email: newcomer@flounder.com
Web: http://www.flounder.com
MVP Tips: http://www.flounder.com/mvp_tips.htm