Recently I tried to explain some poorly designed code to my project manager. All of the manager classes are singletons ("and that's why I can't easily change this") and the code uses event dispatching everywhere that a function call would have sufficed ("and that's why it's so hard to debug"). Sadly it just came out as a fumbling mess of English.
Whats the most difficult thing you've had to convey to a non-technical person as a programmer? Did you find any analogies or ways of explaining that made it clearer?
Thread Synchronization and Dead-Locking.
Spending time on design, and spending time on refactoring.
Refactoring produces no client-visible work at all, which makes it the hardest thing in the project to justify working on.
As a second "not client-visible" problem, unit testing.
I was asked how the internet worked - I responded with "SYN, ACK, ACK". Keep forgetting it's SYN, SYN-ACK, ACK..
(source: inetdaemon.com)
My most difficult question began innocently enough: my girlfriend asked how text is rendered in Firefox. I answered simply with something along the lines of "rendering engine, Gecko, HTML parser, blah blah blah."
Then it went downhill. "Well how does Gecko know what to display then?"
It spiraled from there quite literally down to the graphics drivers, operating system, compilers, hardware archiectures, and the raw 1s and 0s. I not only realized there were significant gaps in my own knowledge of the layering hierarchy, but also how, in the end, I had left her (and me!) more confused than when I began.
I should've initially answered "turtles all the way down" and stuck with that. :P
I had a fun case of trying to explain why a program wasn't behaving as expected when some records in a database had empty strings and some were NULL. I think their head just about exploded when I told them empty string is just a string with 0 bytes in it while NULL means unknown value and so you can't actually compare it to anything.
Afterward I had one nasty headache.
1.) SQL: Thinking in sets, rather than procedurally (it's hard enough for us programmers to grasp!).
2.) ...and here's a great example of demystifing technical concepts:
How I explained REST to my wife
A lot of statements starting with "It's because in Oracle, ..." come to my mind.
The biggest hurdles are around "technological debt", especially about how the architecture was correct for this version but needs to be changed for next version. This is similar to the problem of explaining "prototype versus production" and "version 1.0 versus version 2.0".
Worst mistake I ever made was doing a UI mockup in NeXT steps UI Builder. It looked exactly like the end product would look and had some behaviour. Trying to explain that there was 6 months of work remaining after that was very difficult.
How recursion works...
Why code like this is bad:
private void button1_Click(object sender, EventArgs e)
{
System.Threading.ThreadStart start =
new System.Threading.ThreadStart(SomeFunction);
System.Threading.Thread thread = new System.Threading.Thread(start);
_SomeFunctionFinished = false;
thread.Start();
while (!_SomeFunctionFinished)
{
System.Threading.Thread.Sleep(1000);
}
// do something else that can only be done after SomeFunction() is finished
}
private bool _SomeFunctionFinished;
private void SomeFunction()
{
// do some elaborate $##%#
_SomeFunctionFinished = true;
}
Update: what this code should be:
private void button1_Click(object sender, EventArgs e)
{
SomeFunction();
// do something else that can only be done after SomeFunction() is finished
}
private void SomeFunction()
{
// do some elaborate $##%#
}
The importance of unit tests.
"Adding a new programmer a month to this late task will make it ship later. Never mind, read this book." (The Mythical Man-Month.) Managers still don't quite get it.
The concept of recursion - some people get it really hard.
I sometimes really have hard time explaining the concept of covariance/contravariance and the problems related to them to fellow programmers.
Convincing a friend that the Facebook application I developed really doesn't store her personal data (e.g. name) even though still displays it.
Why it'll take another four weeks to put this app into production. After all, it only took a week to do the rapid prototype. It "works" (or at least looks like it does) so I should be pretty much finished, shouldn't I?
Explanations that involve security, code quality (maintainability), normalized DB schemas, testing, etc. usually come off as a list of abstractions that don't have any visible effect on the app, so it's hard to explain what they really contribute to the project and why they're necessary. Sometimes analogies can only take you so far.
C pointers
*i
&i
Avoiding Dead-Locking in a multi-threaded environment.
I cleared confusion by explaining it visually on a white-board, drawing out two parallel lines and showing what happens when the reach the same points at the same time.
Also role-playing two threads with the person I was explaining it to, and using physical objects (book, coffee mug, etc) to show what happens when we both try to use something at once.
There's really no right or wrong answer-proper for this... it's all experiences.
The hardest thing I have had to explain to a non-tech person was why he couldn't get to his website when traveling abroad but his family member that lived there (with a totally different provider) could get to it. Somehow, "Fail in Finland" wasn't good enough.
The most difficult concepts to explain to people I would label programmers as opposed to developers are some of the most core paradigms of object orientated design. Most specifically abstraction, encapsulation and the king, polymorphism and how to use them correctly.
Expanding on that is the level of complexity of explaining what Inversion of Control is and why it is an absolute need and not just extra layers of code that doesn't do anything.
I was going to comment on Mikael's post, that some people just take the sequential programming and unfortunately just stay with that.
But that really means: two seriously hard to explain concepts:
monads in haskell (usually starting with: "That's like a function that returns a function that does what you really wanted to do, but ...")
deferreds in twisted/python ("That's like... ehhh... Just use it for a year or so and you'll get it" ;) )
Trying to explain why code was executed sequentially at all. Seemingly this is not at all intuitive for some non-programmers (i.e. my girlfriend).
Why you do not need character correct index handling in most cases when you use UTF-8 strings.
It's hard to explain why most software has bugs. Many non-technical people have no idea how complex software is, and how easy it is to overlook unexpected conditions. They think we are just too lazy to fix stuff that we know is broken.
There are 10 different types of people in the world.
The people who understand Binary and the people who dont....
To put it plainly, why development is the most difficult concept ever exposed to man kind. Not related to any programming language, but in general. And no I am not trying to provide myself or you with an ego boost, the only real limitations to this field is your mind.
Why? We don't work with constants and there are no boundaries, the only reason an AI that thinks like a human being doesn't exist yet is due to our own limitations. All other aspects need to adhere to some sort of law, development doesn't care about the laws of physics or any law for that matter hence the term development... evolution.
Related
I don't understand this issue:
Issue: HIS Metriken - Cyclomatic (CR-MET4): [function_name] 13>10
It appears in Klocwork analysis while checking the issues of Code: METRICS.E.HIS_Metriken___Cyclomatic__CR_MET4_
Can anyone support?
Thanks
Do you see all those ifs, elses, loops in that function?
Those are the problem, you need to either design this function's logic more elegantly or split it into more functions with well-defined purposes.
By the way, I can only see that problematic function of yours because I am especially clairvoyant. For this kind of question you should normally show your code, just to be fair towards all those other users which cannot read your mind like I did.
Naaa, not really. The cyclomatic complexity is a measure for number of potential paths through your function. And that you have crossed the treshold of 10 by 3 means your function must be full of control structs, which create many paths.
Ok so this is my first question here. I am currently an IT student and I am taking a fundamentals of programming class. I seem to be spending more time lost and confused than I feel as if I should. We are using Python as the programming language. The topic for this week is arrays and lists. From what I have gathered through reading many other forums, Python does not use array but lists. Therefore the assignment does not make since to me. Any help or guidance would be greatly appreciated.
Create a FLOWCHART and a STORYBOARD for each problem.
Use the information below to create a storyboard (which can be a text based description for solving the problems) and a flowchart (using flowchart symbols to illustrate how you would program) to solve each problem. You may use Microsoft Word® for your Storyboard and Microsoft PowerPoint® for your flowchart.
Problem 1: Create an array that contains the days of the week.
Problem 2: Create a loop to print the content above.
So what would the flowchart for this look like? The assignment next week builds on this by actually writing the program in Python. What would the script look like? Thanks for any help.
This is just for hinting, I won't write your program for you. In your comment, you assigned to the list (you're right, they're not called "arrays" in Python) correctly. Now you need to iterate over it to print each item individually. I'd suggest you refresh your memory in the Python Tutorial on how to control program flow, especially the for statement. Remember, the general idea is:
for item in collection_of_items:
do_something_with(item)
days = ['monday','tuesday','wednessday','thursday','friday','saturday','sunday']
for day in days:
print(day)
Edit:
what would the flowchart for this look like?
This problem is quite simple, try to make your own flowchart. Try to practice thinking at the very first lesson of programming course.
What would the script look like?
It would look like above code. But you can do it better and more professional, try to figure it out.
I have been asked in an interview how one can return more than one value from function. I have answered saying by using pointers we can achieve(call by reference) this in C. Then he told me he is looking for some other way of returning more than one value. I said we can return a struct object but here also he didn't seem to be impressed.
I would like to know others ways to return more than one value from a function.
I have seen this questions being asked here on SO, but could not find anything C specific.
The tricky problem is that the interviewer has some solution they are particularly happy with in mind and they are likely grading you by whether you have the same clever trick as them or not.
You could just name a few ways such as you did, and still not fall upon their secret trick. And if you knew their secret trick, you could well not be impressed with it.
So in these situations, its to turn it from interview into conversation. Once you detect you're not moving towards their ego, you can avoid heading towards the intimidating "I don't know" "I give up" and instead try out the "so do you have any clever solution? Is there an in-house recipe for this at Xyz Inc?" etc.
Any glimpse at their obviously self-impressed solution and you are back on firm ground where you can talk about it and ask them if they have thought about various factors that come to mind and basically interview them.
Everyone loves a good listener, and getting them to talk about their tricks is a good way to get them to leave the interview throughly impressed with you! ;)
There are a few ways:
Return value using the return statement (as you already know)
Return via references.
Return values via the heap.
Return values via global variables.
That depends on what you consider a value. If a value is a piece of information for you, more values could be a struct of values. More values could be also passed via pointers or arrays, even a char* containing a list of (non-zero alphanumerical) values. If you consider a value to be a bit of information a single returned uint32_t may hold 32 values. You could even mess around with signals or sockets or pipes or files.
But for you do not even know the use case and the requirements it imposes on the solution, it's indeed a rather hard task to come up with the right solution (and you actually did come up with some proper solutions ...).
Return a pointer to a structure, or pack several small datatypes into one large datatype, or use global variables.
The first is probably the cleanest way to do it, the other two might have their uses in certain situations.
If we pass the address instead of the true value of the parameters.
Then whenever we refer those parameters we do it with the address.
returning a pointer to structure is the suitable answer.(Obviously, the objective of the program can decide what's the best that can be done). The interviewer might have wanted you to say 'I don't know' which would have shown your lack of confidence in the field. I think you provided good solutions, though not what he had in his mind. You could have asked him about a typical scenario where he wanted multiple values to be returned and then discuss how struct-pointer is a reasonable alternative.
I have question relating to implementation of arrays with Java+ANTLR combo. (I'm mainly talking about java/c style arrays).
So basically I'm asking how do you implement such feature, if there is such example already available or if someone could point me to anything that may point to solve it.
On other hand, I've searched a bit how would possible solution be. Main problem that I see
is that user may create arrays of various dimensions, even go crazy if he or she wants (like creating 5 dimension arrays or worse).
While grammar for something like this is fairly simple, like
new ID (INT (',' INT)* )
back end really gets involved a bit. As I said, user may input any number of dimensions, so array dimensions should be dynamically created. (at least as I see it, maybe I'm over complicating things?)
After searching I did found something that pretty much solves this problem perfectly, here is link to the question:
Is it possible to dynamically build a multi-dimensional array in Java?
Of course, my question is, is this viable example, it is a bit (to say at least), complicated? Is there more elegant solution to it?
Having that in mind, I was thinking maybe answer might be in the grounds of somehow transforming multidimensions
into more linear structure ? Could something like that be useful ? Simple search on stackoverflow pointed many solutions
to this, like:
Algorithm to convert a multi-dimensional array to a one-dimensional array
Would it be worth to search in that direction ?
Now, at the end, having in mind that arrays are really common feature in many languages, I must find it surprising that after searching ANTLR mailing list there is no similar question, which as I previously said leads me to believe that I'm maybe over complicating things ? (Unless I really suck at search?) I would really appreciate feedback.
Your syntax, if I'm not mistaken, corresponds to something like
new char 4,5,6,7
which is kind of strange. I expect that you really meant
new char[4,5,6,7]
However from a purely syntactic point of view, there's no reason not to just store the indices in an array and let the semantic analysis pass worry about it.
I discovered the "FizzBuzz" question today at coding horror. Great article. However, something in one of the user-comments confused me -- here's the quote:
Geez guys - EVERY ONE of you who gave
example code - EVERY ONE - hard coded
the FIZZ and BUZZ conditions...
It sounds to me like this poster is ridiculing people for "hard-coding" conditions, ie :
if(i % 3 == 0)
...
What is point the poster is trying to make? Is there another way to specify conditions in a program?
Thanks for taking the time!
Dan
the FIZZ and BUZZ conditions...
The point of Fizz Buzz is to quickly weed out non-programmers, not find the best programmer. Any reasonable function that meets the specification is acceptable for this test.
If you don't hardcode, great, you extra-pass. But, that doesn't get you out of the hard questions that are following. I usually increase the difficulty with each question, but I don't want to waste time if the candidate totally can't answer simple questions.
There's nothing wrong with hardcoding some conditions.
In the context of an interview, when I know that I'm coding FizzBuzz.java and not Enterprise Fizz Buzz with a database and 1000+ simultaneous users requiring five-nines uptime, it's ideal to hardcode these conditions.
Entry-level programmers, the ones you ask FizzBuzz at least, are to follow specifications and make solutions as simple and elegant as possible. If you're an agile software house, including such features goes against YAGNI and should be discouraged. If the interviewer doesn't ask the ability to use other factors besides three and five, then it wasn't in the spec and therefore isn't needed.
It's meant as a joke.