Related
I know a little bit of ML, and want to implement a learning system by myself,but do not know how to do.Any one can give me a demo or use other method to compare faces?
Here is a related post: https://stackoverflow.com/questions/14079794/how-to-recognize-face-by-geometric-feature-such-as-eyes-nose-mouth.
One can not reasonably answer this question bassed on the above information because of sheer vastness of the subject.
For the start you should know that these problems are usually solved using Machine Learning techniques like Neural Networks. You said you know a bit about ML but as IMHO you might want to read more or take an online Course on Machine learning.
There are some good Courses on Coursera.org one that I like is Machine Learning by Andrew Ng.
These Methods are also described in above mentioned course and there are some good assignments too, which will help you to get the detailled idea behind machine learning.
Guys ! I understood that my previous question did not meant to you guys as per my intentions. I apologize for the same.
Let me pose in a different way.
Take my case, yesterday I faced an interview.
The guy out there asked me that he is trying to develop an application similar to google maps for his windows mobile device.
He asked me to come up with a class diagram for the application.
It was like a bouncer for me.
In such cases, what should be my approach ? where should I start ? How should I look at the problem ?
I hope this is better understood.
I request you to answer me considering that I am an amateur C++ developer who has never worked on any projects from the analysis & design phase
and doesn't know abc's of design.
Thanks,
krisssam
Maybe a bit overkill for an interview, but even there I would still go for 1 and 3 and start with 4.
ask as much specifications as possible, so you know what is expected
When possible/needed, make use cases to get a clear view on how it will be used
Start high level, focus on the main features. Look for preferably less than 6 players (modules) and try to see how they interact. Define responsabilites and interfaces.
Break up these players in submodules and see how these interact (also define responsabilites and interfaces). Repeat until you have implementable entities (classes)
in parallel with 4, for architecture, see how it will be deployed and what language/frameworks/libraries are needed/available.
For google-maps, I assume that players could be the map-database, the map-viewer, the user-input, the search-engine, but I'm not a GUI/GIS/mobile expert.
First you need a clear understanding about what you should be written. Formulate that understanding in English. Now every noun is a candidate for a class. Every verb is a candidate for a method. and nouns that appear in the same sentence are candidates for association.
This sounds quite simple. That's because I simplified it a lot. Actually there is much more to it. Getting a clear understanding about what should be written alone is challenging. If you are interested I suggest reading a book on object oriented analysis and design.
Define the responsibilities that each component of the software will have, then flesh classes around those.
It doesn't relate to the language.
Class diagram - means you need to identify the major objects that "plays" in this app.
The map object and it's data members and actions
the icon objects and it's data members and actions ect...
For reasons I will spare you, I have two weeks to learn some C++.
I can learn alone just fine, but I need a good source. I don't think I have time to go through an entire book, and so I need some cliff notes, or possibly specific chapters/specialized resources I need to look up.
I know my Asm/C/C# well, and so anything inherited from C, or any OOP is not needed.
What I do need is some sources on the following subjects(I have a page that specifies what is needed, this is basically it, but I trimmed what I know):
new/delete in C++ (as opposed to C#).
Overloading cin/cout.
Constructor, Destructor and MIL.
Embedded Objects.
References.
Templates.
If you feel some basic C++ concept that is not shared with C/C# is not included on this list, feel free to enter those as well. But the above subjects are the ones I'm supposed to roughly know in two week's time.
Any help would be appreciated, thanks.
Edit: I want to clarify - I don't expect to study for two weeks and then go and write Quake.
I need to get to a level where given some code and a while to think about it, I can understand it. nuances like ++X vs X++ don't matter as much as knowing what the main keywords are, etc.
This site is your best bet. Although its a great reference anyway, the way the questions are phrased and organised you'll be able to get up to speed quicker:
http://www.parashift.com/c++-faq-lite/
I will be honest with you. In 2 weeks, you won't be able to learn the whole C++.
Let me rephrase that, because no one will ever know everything about C++ (it is very huge and yet it's still growing), you won't be able to learn everything you need to become an expert C++ programmer.
However, if you do have some good programming background, many concepts in C++ will sound familiar to you. This will help you learn complex concepts quicker than novice programmers.
I would suggest you to go to C++ FAQ Lite
because it is the site that lists all the main concepts of C++.
Don't expect to program something enterprisy after going through the site, because that ability comes after you have coded some extensive systems in C++. However, the site will definitely help you to understand what C++ looks like and other people deal with in C++.
GOOD LUCK :)
Thinking in C++, Volume II. Free, well written and available online.
http://www.mindview.net/Books/TICPP/ThinkingInCPP2e.html
I know you said you didn't want to read a book but "Accelerated C++" is probably what you want. It was actually was used in like a 2 week crash course at Stanford from what I remember to get people up to speed on C++.
If you do not have time to go through an entire book, you may try an online tutorial such as the one at http://www.cplusplus.com/doc/tutorial/.
However, it will be useful to go into more depth about common pitfalls and good practice in C++. A good online resource for this is the C++ FAQ lite, at http://www.parashift.com/c++-faq-lite/ .
If you decide to buy or borrow a book, "Effective C++" by Scott Meyers would be a good choice. You do not need to read it front to back, as each chapter is dedicated to a specific problem you are likely to encounter when writing C++ code, and can be read separately.
If you need quick explanations of specific sections of the language, http://www.learncpp.com/ is also a good resource. The caveat is that their webserver is dog slow most of the time (which is unfortunate, because they have some really good explanations).
I am a new to professional development. I mean I have only 5 months of professional development experience. Before that I have studied it by myself or at university. So I was looking over questions and found here a question about code quality. And I got a question related to it myself. How do I increase my code understanding/reading skills? Also will it improve the code quality I will write? Is there better code notation than Hungarian one? And is there any really good books for C++ design patterns(or the language doesn't matter?)?
Thank you in advance answering these questions and helping me improving :)
P.S. - Also I have forgot to tell you that I am developing with C++ and C# languages.
There is only way I've found to get better at reading other peoples code and that is read other peoples code, when you find a method or language construct you don't understand look it up and play with it until you understand what is going on.
Hungarian notation is terrible, very few people use it today, it's more of an in-joke among programmers.
In fact the name hungarian notation is a joke itself as:
"The term Hungarian notation is
memorable for many people because the
strings of unpronounceable consonants
vaguely resemble the consonant-rich
orthography of some Eastern European
languages."
From How To Write Unmaintainable Code
"Hungarian Notation is the tactical
nuclear weapon of source code
obfuscation techniques; use it! Due to
the sheer volume of source code
contaminated by this idiom nothing can
kill a maintenance engineer faster
than a well planned Hungarian Notation
attack."
And the ever popular linus has a few words to say on the matter.
"Encoding the type of a function into
the name (so-called Hungarian
notation) is brain damaged—the
compiler knows the types anyway and
can check those, and it only confuses
the programmer."
- Linus Torvalds
EDIT:
Taken from a comment by Tobias Langner.
"For the differences between Apss Hungarian and Systems Hungarian see Joel on Software".
Joel on Software has tips on how to read other people code called Reading Code is Like Reading the Talmud.
How do I increase my code
understanding/reading skills?
Read read read. Learn from your mistakes. Review answers on SO and elsewhere. When you can think back on a piece of code you wrote and go "aha! I should've done xyz instead!" then you're learning. Read a good book for your language of choice, get beyond the basics and understand more advanced concepts.
Then, apart from reading: write write write! Coding is like math: you won't fully grock it without actually solving problems. Glancing at a math problem's solution is different than getting out a blank piece of paper and solving it yourself.
If you can, do some pair programming too to see how others code and bounce ideas around.
Also will it improve the code quality
I will write?
See above. As you progress you should get more efficient. It won't happen by reading a book on design patterns. It will happen by solving real world problems and understanding why what you read works.
Is there better code notation than
Hungarian one?
It depends. Generally I avoid them and use descriptive names. The one exception where I might use Hungarian type of notations is for UI elements such as Windows Forms or ASP.NET controls, for example: using btn as a prefix for a Submit button (btnSubmit), txt for a TextBox (txtFirstName), and so on but it differs from project to project depending on approach and patterns utilized.
With regards to UI elements, some people like to keep things alphabetical and may append the control type at the end, so the previous examples become submitButton and firstNameTextBox, respectively. In Windows Forms many people name forms as frmMain, which is Hungarian, while others prefer naming it based on the application name or form purpose, such as MainForm, ReportForm, etc.
EDIT: be sure to check out the difference between Apps Hungarian and Systems Hungarian as mentioned by #Tobias Langner in a comment to an earlier response.
Pascal Case is generally used for method names, classes, and properties, where the first letter of each word is capitalized. For local variables Camel Case is typically used, where the first letter of the first word is lowercase and subsequent words have their first letters capitalized.
You can check out the naming conventions and more from the .NET Framework Design Guidelines. There is a book and some of it is on MSDN.
And is there any really good books for
C++ design patterns(or the language
doesn't matter?)?
Design patterns should be applicable to any language. Once you understand the concept and the reasoning behind that pattern's usefulness you should be able to apply it in your language of choice. Of course, don't approach everything with a "written in stone" attitude; the pattern is the goal, the implementation might differ slightly between languages depending on language features available to you. Take the Decorator pattern for example, and see how C# extension methods allow it to be implemented differently than without it.
Design Pattern books:
Head First Design Patterns - good beginner intro using Java but code is available for C++ and C# as a download (see "book code and downloads" section on the book's site)
Design Patterns: Elements of Reusable Object-Oriented Software - classic gang of four (GOF)
Patterns of Enterprise Application Architecture - Martin Fowler
If you're looking for best practices for quality coding in C++ and C# then look for the "Effective C++" and "More Effective C++" books (by Scott Meyers) and "Effective C#" and "More Effective C#" books (by Bill Wagner). They won't hold your hand along the way though, so you should have an understanding of the language in general. There are other books in the "Effective" series so make sure you see what's available for your languages.
I'm sure you can do a search here for other recommended reading so I'll stop here.
EDIT: added more details under the Hungarian Notation question.
I can't speak for everyone else, but in my experience I've found that the best thing I learned about making readable and/or in general better code was reading (and ultimately cleaning) a lot of other people's code. Some people may disagree with me but I think it's invaluable. Here's my reasoning:
When you start programming, its difficult to determine what is crap vs. not crap vs. good. Being logical, rational and extremely intelligent help in making good code, but even those factors don't always contribute. By reading others works and doing the dirty work, you'll have gone through the experience of what works and what doesn't. Eventually, you'll be able to mentally navigate those minefields that others had to cross and you'll be prepared to avoid those identical minefields.
By reading other's works, you gain insight into their mind and how they tackle a problem. Just from an architecture or technique aspect, this can be very useful to you whether their
tactics were good or bad. By reading other peoples successful or unsuccessful implementation, you've gained that knowledge without putting in the actual time it took them to learn it.
Design patterns are extremely useful. Only time and experience with them will help you in knowing what the appropriate pattern for whichever problem. Again, read other peoples' code for this if they've successfully built some pattern that may be useful for you.
When dealing with extreme problems where people's work falls short, you learn to research and dive into the internals of whatever system/language/platform/framework you're working with. This research ability on your own is very useful when all else fails. But you'll never know when to start looking or for what until you get through the crud of other people's work. Good code or bad, it's all valuable in some form or fashion.
All these notations and formats and nomenclature are helpful, but can be learned or implemented rather quickly and their payoff is fairly substantial. By reading code from other people, you'll develop your own style of logic. As you encounter other peoples work and the tremendous amount of effort it takes to read through, you'll learn what logical pitfalls to avoid and what to implement the next time for yourself or even how to fix bad code even faster.
I've never felt as if I was a great programmer. Not to say I'm a bad one either, but I feel confident in my abilities as my experience has taught me so much and my ability to adapt to every situation is what makes me a solid programmer. Learning from other people and their code has helped me. Whether their work was good or bad, there's always something you can take from them and their experience, add it to your memories, knowledge, etc.etc.
Ask other people to read your code! Try and see if you get a fellow coworker or similar to have a code review with you. Having someone else comb through your code and ask you questions about your code will provide new insights and critiques to your style and techniques. Learn from your mistakes and others.
Just to give you a bit of encouragement, I've been a professional programmer for 30 years now, and I still find reading other people's code very difficult. The major reason for this, unfortunately, is that the quality of the code follows Sturgeons Law - 90% of it is crap. So don't think it's your fault if you find it hard going!
The biggest improvement in readability of my code came about when I started liberally using white space.
I found this article on Joel on Software to be very relevant to the Hungarian notation debate.
It seems that the original intent of the notation was to encode type information that wasn't immediately obvious- not whether a variable is an int (iFoo), but what kind of int it is- such as a distance in centimeters (cmFoo). That way, if you see "cmFoo = mBar" you can tell that it's wrong because even though both are ints, one is meters and the other is centimeters, and thus the logic of the statement is incorrect, even though the syntax is fine. (Of course, I personally prefer to use classes such that that statement wouldn't even compile, or would do the conversion for you).
The problem was at some point people started using it without understanding it, and the world was cursed with lots of dwFoos and bBars.
Everyone needs to read that article- Making Wrong Code Look Wrong
How do I increase my code
understanding/reading skills?
Reading code is like dancing by yourself. You need a partner, and I suggest a debugger.
Stepping through code with a debugger is a true, lively dance. I recommend getting a quality, open-source project in the language of your choice, and then step through with the debugger. Concepts will come alive if you ask "why did that happen?", "what should happen next?".
One should ultimately be able to reason about code without a debugger; don't let it become a crutch. But that said, it is a very valuable tool.
Reading code is a lot like reading literature in that you need to have some insight into the author sometimes to understand what you're looking at and what to expect. They only way to improve your comprehension skills is by reading as much code and possible and trying to follow along.
I think a lot of what is mentioned here is applicable to coding...
Reading and understanding skills are a question of time. You will improve them as you get more experienced. Also depends in the quality of the code you are reading.
Keep in mind that sometimes it's not the best idea to learn directly from what you see at work. Books will teach you the best practices and you will be able to adapt them to yourself with the experience.
I am reading the Head First Design Patterns at present and it is very useful. It presents the information in a novel way that is easy to understand. Nice to see they have a C# version for download.
There will always be struggles with reading code unless you are Jon Skeet. This isn't to say that it is a big problem, rather that unless you can eat, sleep, breathe in that programming language, it will always take a little time to digest code. Looking at other people's code is certainly a good suggestion for helping in some ways but remember that there are many different coding conventions out there and some may be more enforced than others, e.g. interface names start with an I to give a simple example. So, I guess I'm saying that even with Visual Studio and Resharper, there is still a little work to understand a few lines of code since I can't quite write out sentences in C# yet.
1) Educate yourself. Read relevant literature.
2) Write code
3) Read code
4) Read relevant blogs.
Visit http://hanselminutes.com . He is a programmer from microsoft. Even though you don't program on microsoft stack, it's good to read through. There is a podcast in there that answers this question.
Another suggestion is to make sure you have the appropriate tools for the job before you start digging into a piece of code. Trying to understand a code-base without the ability to search across the entire set of files is extremely difficult.
Granted, we very rarely have the entire set of files, especially in large projects, but whatever boundaries you draw, you should have good visibility and searchability across those files. Whatever lies outside those boundaries can be considered 'black box' and perhaps lies outside the scope of your grokking.
There are many good open source editors including Eclipse and the CDT. Spending some time learning how to effectively create projects, search across projects, and enable any IDE-specific tooltips/helpers can make a world of difference.
I have been learning C++ for three months now and in that time created a number of applications for my company. I consider myself fairly comfortable with C++ / MFC and STL, however I don't just want to be an OK programmer, I want to be a good programmer. I have a few books on best practices but I was wondering if anyone could suggest reading materials that helped them and any disciplines which should be encouraged?
Thanks!
I would start with the Pragmatic Programmer, Code Complete, Refactoring and Design Patterns.
For C++, Scott Meyers books are very good, and will help take you to the next level.
If you don't already have it C++ by Bjarne Stroustrup, 3rd Edition
Uhm... Teach Yourself Programming in Ten Years (Peter Norvig)
3 months into c++ and you're already comfortable with it? Sheesh, I've been learning c# for over a year and have taken numerous Microsoft courses and I'm nowhere near comfortable with it.
That being said, you'll hear Code Complete tossed about as a very good book. I'm in the process of reading it now.
Marshall Cline's C++ FAQ Lite.
Herb Sutter's Exceptional C++.
Large Scale C++ Software Design by John Lakos gives guidance on design methods that will make your C++ more maintainable. It is pretty hefty but you can dip in and still get some benefits.
Somewhat off-topic: rather than suggesting books to learn, I'd like to mention some broad topics to consider.
Threading. This one is not much in demand if you use MFC, but in many other areas it's indispensable. The mechanics of threading APIs are easy to pick up, but learning all the corner cases takes a lot of time and practice.
Closures, Map-Reduce and other lisp-like techniques. Find out what they are, why they are not supported in C++, and how they are imitated in C++ (functors, and many other cases of stateful callback objects). For this I actually have a book: "Structure and Interpretation of Computer Programs".
Command Line. This gives you an idea on when not to code your own programs. Command line would be Unix command line - I don't know about MS's latest experimentation in this are, but cmd.exe is awful. Get Cygwin and start experimenting.
Scripting languages. This gives you an idea on when not program in C++. My favorite is Perl, but many people say Python, Ruby and whatnot. Hey, learn XSLT if you're so inclined!
I am sure I left out other areas. I'll mark this as Community Wiki - feel free to add.
Good blogs:
Guru of the Week, and all the books by Herb Sutter. Those will give you quite a lot to chew already.
Modern C++ Design by Alexandrescu if you want to get a good feel for what you don't yet know, and probably don't want to know.
Code Kata's for practice!
I have read several (not complete but some parts) of oreilly books on VB.net they are quite good, but if you want to be pro and have the time...
You can try out MSDN forums, help other people and discuss with them hard and complex problems, I think it's the best way..
learn another language. even if you won't use it, it's great for mind-opening.
I'd advice Lua, Scheme and Python. but almost anything else would do. (the most different from C, the best)
Josuttis and Vandevoorde - Templates: The Complete Guide
As I see, nobody mentioned Bruce Eckel brilliant books "Thinking in C++". IMHO, it`s one of the best books to start your C++ development from. From my point of view, first volume is more helpful that the second, but both of them worth reading.
http://www.amazon.com/Thinking-C-Introduction-Standard-One/dp/0139798099/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1227890306&sr=8-1
I lot of folks can suggest more modern, up-to-date books. But I still recommend The Annotated C++ Reference Manual by Margaret A. Ellis & Bjarne Stroustrup.
The ARM was published back in '90. It's become somewhat outdated with respect to templates. STL is (obviously) absent. (Though the website at sgi.com does a good job of covering STL!)
However, the ARM is dirt cheap (used). (Shipping will exceed the cost of the book.) Its signal-to-noise ratio remains off the scale. It's very good at digging into C++'s dirty areas, explaining what was done & why.
I still use it as a reference. I rank it up there with K&R.
Dietel/Dietel "How to program C++"... I still have this book on my desk (10 years in).. Every once and a while I re-read a chapter. I'd definatly get the Code Complete, as other have suggested. Infact read that first.
To get a better understanding of object orientation, spend some time in a Smalltalk. Squeak is a free download. Then read Richard P. Gabriel's Patterns of Software and thereafter his Objects have Failed.
Thinking in C++ - Bruce Eckel
Symfonia C++ Standard - Jerzy Grębosz
If you do nothing else, program.
When you are not doing that read about programming and when something strikes you as interesting, go implement something with that knowledge. I've found that this is the only way to really set the principals.
Staying up to date on blogs can be fun, but it is scattered knowledge. It seems to distract more than help. But combined with google and a desire to research something specific can really cough up tons of information. But dont' just subscribe to alot of rss feeds and expect to get better.
I think really studying specific topics helps expand your ability. Research topics that intrigue you, meet people doing things like you (conferences, user groups, irc, facebook, stackoverflow, etc) and above all practice your art.
You can check out the Boost library and a number of the books written about it. While this may not have been what you had in mind, IMO, the Boost libraries are examples of well-designed modern C++ libraries that use the features of the language in pretty much the way they should be used to create among the most effective solutions for their problem domain. Granted of course, there are bizarre libraries like preprocessor and MPL which make you wonder if you'll ever have any use for them, but they're all round quite good. From my own experience, exploring the library and its literature has given me insight into how C++ can be used effectively.
Boost
Beyond the C++ Standard Library: An Introduction to Boost