How to detect certain face on the photo - language-agnostic

I was just having a nap and then that crazy idea came into my head. Here it is.
We have 2 different photos with face in each. How can we detect if there is the same person on that two photos?
Is it possible to do that? If yes, can I do it with Java or PHP? What the way to do it? Any ideas? Maybe each face has a "algorithm" or something which could help us?
Thank you very much.

It's not an trivial solution (and cannot be covered in an SO answer); you can start by reading papers on facial recognition. If this is something you really want to do, be prepared to read a lot of background information first before you actually start writing code. This subject matter is the basis for a lot of people's doctoral and masters theses. In this case, language is not as important as the algorithm. Also be prepared for lots of math. At the very least, you'll learn something cool. :)

I was freelancing a very similar task. Its not fun. almost impossible to build face recognition - face detection is easy, recognition is the tough part... the algorithm is generally a guarded secret as I've seen.
But I did find this: http://face.com/
Face recognition API. Feed it data, it feeds you names and details you've previously fed it. You have the ability to check to see if a face exists.
If you make a lot of requests or start working at an enterprise level - they charge.

The language doesn't really matter as long as it has the tools to do number crunching on the image data. Facial recognition is too big of topic for a forum post like this. I would just google "facial recognition algorithms".

I agree with the others that this is not trivial.
detect a face in both photos
normalize the facial data
compare the data to see if they match

Related

Toy projects for new programers

When I was first started teaching myself programming, after finishing a tutorial I would feel like I still couldn't do anything in the language. So, I looked around to find something to work on. Since I had just learned a few of the basics, the amount of work involved in finding, reading and adding to an open source project seemed insurmountable. Instead I started on a couple toy projects, which ended up being incredibly beneficial.
Having seen a lot of questions from beginners similar to "what should I do now?" and a lot of answers similar to "start working for an open source project" has made me think there has to be better advice for a new programmer. While working on an open source project surely gives great experience, there is a perceptible barrier to entry.
Instead, I think it would be great if new programmers were prodded towards working on a toy program related to some interest they have. Since there are so many directions that programming can take you, I think it would be interesting to list some simple (but fun/rewarding) projects grouped by the direction the new programmer is looking to pursue. Such as:
Game Design:
Write a text adventure (like Zork)
Natural Language Processing:
Create a program that writes meaningless, but grammatically valid essays.
I recently asked a similar question (Diverse resource of problems to show merits of different languages) and got links to sites that provide problem sets, as well as validation. Check out:
http://www.codechef.com/
https://www.spoj.pl/problems/classical/
http://wiki.python.org/moin/ProblemSets
http://projecteuler.net/
Although these problems don't oftem amount to projects, they are still interesting. I'm interested in seeing what people come up with here.
I actually think that a TopCoder approach might be better... programmers can still pick topics of interests, but they're actually working for a prize on a REAL project and they get feedback. Frankly speaking, TopCoder is a bit of a bloat and as far as I can tell, they don't allow people to make free competitions. It would be great if there is a TopCoder/StackOverflow type of site: people can submit code, get voted on their implementation and just have a good time!
I'll even pitch my idea, I'm starting to work on my own version of TopCoder/StackOverflow hybrid monstrosity called MyDevArmy (although I have not done anything so far except buy the domain).
Write a program which renders Wolfram automata (esp. Rule 110).
See YelloSoft for example code.
Start by writing a Blackjack simulation. Choose whichever strategy you want for the first run.
Next, start adding additional runs for different strategies like hitting/standing when your hand's value is 15 vs. 16 vs. 17 vs. 18, and whether the hand is soft or hard (an ace's value being counted as 1 or 11). The dealer's strategy will be constant, as they really are in casinos.
By the end, your program will run, say, 1000 instances of each strategy combination. It will print out a summary of the rate of hand wins (percentage of times you beat the dealer) for each stand value and hard/soft combination.
This is easily one of my favorite projects I've done and it can really cement some techniques in the language of your choosing. Plus, if you have the initiative to start learning some of the (fairly simple) discrete math that's involved in coming up with the odds of these situations as a side project, you can come away with an even better experience. Who knows, maybe you could ditch this computer stuff and take up card counting?

Programming practice

I've decided to get some experience working on some project this summer.
Due to local demand on market I would prefer to learn Java (Standard and Enterprise Editions).
But I can't even to conjecture what kind of project to do. Recently I had some ideas about C. With C I could to contribute to huge Linux projects. I don't mean that my work will be surely commited. I could get the code and practice with it. But C it's not right thing to get good job in my area. In case of JavaSE there is a chance to develop some desktop applications. But thinking about JavaEE I get stuck. I'll be very thankful for answers.
CodingBat.com will give you good core Java practice.
Project Euler is still the best for all around practice. You can use whatever language you'd like to solve the problems there.
For actual projects, I almost always start on something easy like a Twitter client. It gets you exposure to all the basics along with UI and network communication. You can work up from there. Just don't start with something so overwhelming that you can't figure it out and want to give up. That's not going to get you anywhere.
The best advice is: work on a project that you have personal interest in. Something based on your hobbies, maybe.
If that doesn't work, make a blogging / CMS engine. Or an online photo album. Or an eStore. The world doesn't really need another of any of these things, but it will give you some good practical experience with JavaEE.
Another benefit of "re-inventing the wheel" (for learning) is that you have probably already used systems like these described above, and you have a good idea of how it can work, and maybe you have your own ideas of how it could work better. That can make requirements much simpler, and also will give you a sort of benchmark so you can see how close you can come to building a tool like the "real" ones out there. And if yours is really great, well, maybe release it and see what happens. ;)
There are many Java-based projects on SourceForge. Tinker with one you find interesting.
I've implemented either a betting pool or a Baccarat game in almost every language I've
learned.
This type of software covers:
Dates and times, with calculations
Currency types and things that can be converted to and from currency.
A discrete set of rules that is easy to test
States, transition between states and multiple entities responsible for state transition
Multiple users with different views of the same model End conditions
Multiple player blackjack and poker would work also.
One caveat is that in my day job I work on financial systems and there is a huge overlap
between things to consider when writing a multiplayer game of chance and a trading system.
build an address book. the concept is simple, so you're not stuck on "what" to write. You can focus on learning your chosen language. You get experience in working with a database, java ( insert any language here), and UI design.
when you decide to learn another language you can create the same thing. Since the database has been created already, you can focus on the language itself.
the concept of inputting data, storing data, and retrieving data is central to a lot of applications.
Have a look around http://openhatch.org/ for a project that sounds interesting.

Beyond simple coding: Where to go from here? [closed]

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I've been coding since my early teenager years. I started out with HTML, went on to PHP/MySQL (created my own forums, social networking sites, etc..) and then branched out into more traditional languages such as Java and C++ (also picked up a little VB .NET in high school). I'm most familiar now with C++ as that is the language of choice taught to us in Computer Science II (skipped Comp Sci I) at RPI. I now feel like I have a very good knowledge of how to program from this class (the homework assignments were brutal).
It is now summer and I am interning at a company that is providing me some level of new experiences with programming, but I want more. I want to feel the incredible satisfaction that I got out of my computer classes at RPI whenever I finished a long assignment (generating every possible wordsearch from a set of words to include and exclude comes to mind).
My question is, where do I go from here? I tried following a tutorials online, but they were all too simple. I then tried heading over to sourceforge and helping out with various projects. But, as soon as I downloaded the code I got lost in its complexity. I have never created actual software of a real life applicapable scale. And I don't know where to get started. How do you transition from programming knowledge to actuall creation of software?
I'm also open to learning new languages (javascript/jQuery, ASP .NET, C#, Python), or using new libraries and/or frameworks with c++ (we only used the STL in Comp Sci II) and other languages. Again my question is, where do I go from here? And I am welcome to all possible answers.
Thanks Much,
Michael
You could join a big open source project, you'll learn a lot and accomplish something cool.
EDIT after comment: If this is too complicated for you, try starting a "real" project. I say "real" because it should be something that you want to do, not a "create a blog" or "how to do a loop". For instance last year I created a fully functional project management system that I now use for some of my projects. If this is real, you will be more motivated and you will want to get this done.
Pick the technology you want for it. I'd recommend Ruby on Rails because it's awesome and full of interesting concepts that will improve the way you code overtime (DRY, RESTful, MVC...)... but you can pick whatever you want.
Try to create your project using what you know and basic tutorials. You will get stuck and have to learn some more in order to get the features you want going. To me that's the best way to improve the way you code and general programming knowledge.
Since you'll start the project from scratch, you'll see where to start and how this will evolve. I'll take the project management tool. We started with "A project has todos" and we ended up with all kind of other features such as a complex calendar, a full ajax interface, a embedded chat...
Once you see how you did this, try doing the same with a friend of yours to get a fealing of teamwork in development. Learn how to use SVN, basecamp... learn about software development processes (Agile!), peer programming..
There's a lot to experience! Then you could give open source another try.
Hope that helps
I'd recommend trying a pure functional language, such as Haskell. It's a completely different way of looking at programming, and I found it very satisfying.
I recommend the book Real World Haskell for learning it.
Edit: In response to comments, my interpretation of the question is where can he go from here as a programmer. Functional programming is a logical direction. For someone learning functional programming for the first time, Haskell is nice because it doesn't really allow for imperative programming practices. Furthermore, it has basically all features you will find in other functional languages, which means it will be easy to pick up other functional languages.
I would suggest looking at Project Euler. It's a great and fun way to learn a new language, and it does provide that level of satisfaction when you solve the problems. They offer a huge range of problems at all levels of difficulty.
I think the best way to improve your skills as a programmer is to do what programming was intended for: solve problems. I'm sure you've been playing around on your machine and at one time thought to yourself "I wish there was a program that did this..." or "I wonder if there are any programs that do X..." Instead of just googling to see if someone else wrote it, write it yourself. Start with something small, and gradually make it more complex. Add features. Allow yourself to fail, and when you do, ask yourself (or us at stackoverflow) how to overcome that obstacle. Once you have the basics of programming, everything else is just making big things out of littler things, and the little things are usually pretty easy.
When you are making something you know you will actually use, it's more fun and more gratifying when you finish.
Do you understand all of the following and how they work?
Linked lists (single and double)
Sequential vs. binary search
Binary trees
Stacks
Red-black trees
Algorithmic complexity and big O notation
Recursion
Hash tables and hashing algorithms
If you don't feel completely conversant in any of these, take a class in data structures and algorithms.
It seems like you've experienced many languages, but have not created a real-world application. Creating software in any of those languages will bring you to a new level.
PS: Creating software is much more than just knowing how to mess around with a language.
Check out Design Patterns.
I believe that's beyond mere simple coding.
You could offer your abilities to a non profit or a friend or someone who needs a website or program built.
Tell them you can do it for free and then just go for it. As you start to make it you'll start to see what you need to learn.
For example I bit ago I had the program Peel www.getpeel.com on my Mac. But sold my Mac for Wind as I am traveling.
Seeing that there was nothing for Windows (or nothing I could find) like Peel. I build my own in PHP and am up to a 4th rebuilding of it as I learn betters ways to do each new thing I am learning.
You've got to find a particular type of functionality that interests you. For me it's been basic socket programming and making my own protocols. I got that feeling when I was able to create a functional file uploading control that worked in conjunction with a file upload service on the server which I had created. The protocol handles authentication, chunking and hash comparison. Sometime soon I plan on incorporating file-resume functionality as well.
Well my advice will be to find a problem/project you are interested in and try to code it. Trying a real problem is something that drives you. Find something not to complex but not too simple. Something to try when starting a new language is to write some tools. You can for example program a python script that print metrics on a C++ project. You can write a tool that extract some statistics from a website you use, etc. When I learn programming game programming was quite fun (I was young :-) ). You can try to program some simple game using a 3D engine like Ogre3D for example. Participate in an opensource project is great too but as you stated perhaps a bit overwhelming for now ;-)
Find something you like and that has a REAL useful goal for you. You will thrive to solve the problem and learn a lot along the way !
I think the transition from the kind of finite tractable problems that are part of class projects (and some internships) to "real world" projects is quite tough. Sounds like language syntax, getting bugs out of code etc. is something you are comforatble with.
When we come to larger projects, probably with many release cycles, with developers working together, different kinds of problems emerge. I remember being shocked when I saw my first big project plan - what a small propertion of the time was actually writing code!
The thing I found helpful as a junior was "Sitting By Nelly", I was lucky enough to work for enlighted employers who put me with very experienced and helpful developers. Sometimes to work with, sometime to work alongside. I reckon that helped me get over the hurdles you describe.
So, I reckon you need to find employment of this kind. Be less concerned about specific technologies, salary etc. Look instead for the culture and level of responsibility you would have.
I think you should really start a "real world application" as suggested here. You will see that a real project requires a bit more than just knowing the language.
I suggest you find some simple problem you had issue with, and make a software that solves that issue.
For example, if you want some kind of software that checks RSS feeds every 5 minutes and makes a little pop-up as soon as a new one comes along. Or you want a program that will let you do simple presentations by just dragging a few pictures in.
Then whatever you choose, start by making the simple solution to the problem and extend from there (like do different settings, extra features etc.)
I've looked for the answer to this question for a while now. Most all of the suggestions are usually either help an open source project or build something that interests you. I'm starting to realize that those answers are vague because what's 'interesting' or 'valuable' experience and how to get started doing it is completely subjective. Also, there's only one way to get real experience, which is to work on real projects. It's difficult but find a project, personal, open source, or otherwise that will increase your knowledge in a technology or platform that you think will hold your interest. Then just dig in. It doesn't have to be of earth shattering importance, just valuable in relation to your own goals.
There is no magic bullet transition from academic puzzle solving programs to real world applications. The best way to learn is just to jump in head first. It will take you a very long time to learn what you need to if you only ever look at your own code. You need to be looking at code written by professionals and struggling to understand why it works the way it does until you do understand it.
It seems overwhelming at first, but you will quickly start to see patterns if the application is at all logical. Well written code will be separated in logical ways, so you should be able to pick it apart one layer at a time.
For example, you could try a bottom up approach where you try to understand how the database interactions are handled before looking at the code that uses the database layer. You keep going upward until you get to the GUI event handlers.
Large enterprise applications can be even harder to understand because there might be a lot more than one executable, or component. Try to stay focused and learn what the component is responsible for doing, and then pick it apart a piece at a time.
You will see that there are not just patterns at the function and class level, but at higher levels as well. This makes it simpler to understand what is going on when you understand those patterns.
Try to find an internship or co-op position. I was in a similar situation after my first few courses. I took a co-op position sophomore year and I learned so much more on the job than I did in class. Class is great for teaching you theory and the basics. I learned C# on my first project on my co-op and that got me my second co-op position at another employer (wanted to see how it was working at a small company).
This past spring, I accepted a position at my first co-op employer, reworking my first major project I had started on my co-op. I have a list of side projects I also want to complete, which will help round out my skills, as well as learn some other languages.
So my suggestion is try finding a job where you can have a great mentor. On my second co-op, I learned alot of the coding standards that I code against from my supervisor. He was a great teacher, and really had some great input, and explained why things should be done certain ways.
You will almost certainly go nowhere unless you find something that interests you. Figure out what is interesting, and then how to write software involving it.
The only way to begin is to begin! There is really no other way... The best answers you get would always tell you this. You have the knowledge, now put it to work!

How can I become better at realizing how to solve a particular problem?

I have become pretty fluent in a few different languages now, but I seem to have a hard time actually figuring out the best way to go about solving particular problems. What are some ways to go about getting better at the actual problem solving of programming.
Experience. Solving something completely new is hard. The best way to solve problems is to try and find a problem that you've solved before, and that is similar, and adapt you solution to the new problem. So until you have experience with many different kinds of problems, it's hard to solve new problems that you come across. Visiting sites like this and reading questions and theirs answers are a great way of learning how others solved problems that they encountered.
Basically, "just do it". When you have to make a choice, just make any choice (except flipping a coin).
Once you have something that works, then sit back and scratch your head about what you did wrong and how to do it better.
If you have absolutely no clue how to do even that, just solve a part of the problem completely and move on.
I suggest checking out this book. They aren't the best kid on the block, though they want us to think they are...but they did well with Basecamp.
When all you have is a hammer, everything begins to look like a nail.
So, make sure you're well versed in algorithms and data structures. When you study them, think hard about what sort of uses a particular algorithm is good for.
Ask someone else. Someone in your office, on Twitter or SO, or even your wife. People with no technical knowledge often come up with simpler solutions.
If you must solve it on your own, try one of these others:
Do a quick search for another person or project which has tried to solve your problem. If they have a blog, documentation or source code, you might be able to learn from their implementation.
Come up with at least TWO solutions and pick the best one.
Pretend you have 15 minutes to solve the problem before the civilized world is destroyed by Nuclear War / Skynet / Permanent endless re-runs of Seinfeld, you might think of something much simpler which gets 99% of the work done.
The book is a set of heuristics to go through when solving a problem. Read about it on Wikipedia. Buy it on Amazon.
By solving actual problems. Practice makes perfect.
If you have time to become fluent in multiple languages, my guess is that you haven't spent much time doing any actual work. If you have a job, it might be time for a new one. If you're still in school, do you have any interest in starting a project for yourself or contributing to one that you use regularly?
It might help to know what kinds of problems you're having difficulty solving.
Go find an open source or free project you can get excited about and contribute. I learned a lot by signing up to code for my favorite video game modification.
Experience.
Study really only goes so far. Find something fun and small. Do it.
One way that seems to work for a lot of people is to pick use a book like Programming Challenges as a guide, and focus on solving problems of a particular type. For example if you're weak in an area like graph problems or dynamic programming, find a set of problems on an online judge and work through them. You'll start to recognize patterns and be able to classify problems.
Google for an answer. Chances are someone else has solved the same problem or a similar problem before.
Ask on SO. :)
Read some textbooks or online articles about design patterns.
Problems may have many solutions, some simpler and some more complicated. Don't get stuck thinking there is only one solution. Just go with the simplest solution that makes the most sense in the context of your application.
After years of experience you'll be able to think of your own solutions to most problems. :)
Study Algorithms!
Search and get a hold on as many examples, books on the subject programming or otherwise, etc.
Problem solving skills can also be improved by playing tactical games.
These made me Enjoy problem solving and become better (not necessarily good) at problem solving:
Chess and igo
I like this general method:
List the possible solutions with their strengths and weaknesses
(This will push you to briefly taste all of them)
Chose the best one and make your design on it
(If you find any heavy obstacle, reconsider other options)
Implement
most importantly, on every step, learn
The best way is probably to learn form a master if that's an option. Especially if you can find someone familiar with the problems your addressing.
Generally the more tools we have at hand the more options we have for tackling a problem. I agree that's important to always code and to always deliver something that works (however inelegant it is). But I think we need to increase our skills/knowledge in many directions:
Language skills (know your language(s) in depth)
Programming paradigms (Imperative, Object, Functional)
Framework knowledge
Algorithms
Patterns
Date-Structures
Methodologies (Agile, DDD, BDD, ?DD)
Tools
etc
You can get a lot of skill through on the job just-in-time-learning, but I usually have a pet subject at any time that I'm trying to get a deeper understanding of, typically this means getting the book and reading it cover to cover.
Work your way through Project Euler, and look at other people's solutions to the problems. Almost every problem will have been solved in a way that wouldn't have occurred to you, and usually with greater efficiency.
I think that there is a lot more than raw experience involved in becoming a good problem solver - because I've seen poor problem solvers with lots of experience.
Here are a few tips but you can find many more around the web.
Look at a number of problems and
figure out what they have in
common. The greater the generality
with which you understand the
solution to a problem, the more you
can apply it to other problems.
Try to discover approaches which
good problem solvers use to solve problem. But don't assume anyone has monopoly on problem solving
If you read Richard Feynman's
books, you'll notice that he
considers many different routes to
get to his goal. Don't narrow your
approach prematurely
Be positive. Assume that you can find
the solution to anything. Your state of mind matters. Enjoying the process of problem solving makes it much easier
Don't beat your head against the wall. If you don't
seem to be making progress with one approach, try another approach
Always be looking for more ways of
solving problems and more insights
into the process of problem solving itself
Be willing to work. It still can take a lot of effort solve some problems
The more different fields of study you know, the more viewpoints you have. I have a strong math background and I find it very useful for many problems. Physics, music or any different viewpoint might be useful
Practice solving problems.
Take an algorithms or discrete math course.
Here some tools that I've used in the past to help me understand a particular problem and its solution. I don't always use them today, but they helped me to learn how to think about breaking down a problem and coming up with a solution.
Class-Responsibility-Collaboration (CRC) cards
One card per class, details the responsibility of the class and what other classes it collaborates with. Using cards you can layout your design for the solution and see where you have too much coupling or too much responsibility. They allow you to think about the design in a lightweight manner before committing to code.
Use cases
Either actual structured use cases that describe user interaction with the system or even briefer stories or story cards. I still use stories, though I capture them in a wiki instead. This allows you to capture the interaction with the system in an informal way. Stories are basically placeholders for conversations that you need to have with the customer about what is supposed to be done. Using the collected stories, you start getting a grasp on the overall intention of the code. You can also start seeing how things interact and what works with other things. This is really the beginning of design.
UML Diagrams - particularly interaction diagrams
For awhile I used these a lot. It really helped to see how things actually worked together under the hood. I will still diagram, informally, some complex interactions to make sure I don't miss anything important. Going through a lot of these really helped me to think about how my objects interacted and now it is sort of second nature to think in terms of interactions.
Class diagrams -- a really high level view of the code.
These allow you to see your code structurally, especially if you can break the diagram down into components or layers of architecture. Mostly I use these now to explain the code to other people when necessary. When starting out these provide a pretty good visualization, though, if you're struggling with the bird's-eye view of the code.
The best advice I can give you if you try these is to follow the "rules" until you really have a good grasp of what is going on. Once you feel like you have a better understanding of what they provide, you can use them or not, or modify how you use them to keep only what is helpful and let the other stuff go.

What's your most controversial programming opinion?

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This is definitely subjective, but I'd like to try to avoid it becoming argumentative. I think it could be an interesting question if people treat it appropriately.
The idea for this question came from the comment thread from my answer to the "What are five things you hate about your favorite language?" question. I contended that classes in C# should be sealed by default - I won't put my reasoning in the question, but I might write a fuller explanation as an answer to this question. I was surprised at the heat of the discussion in the comments (25 comments currently).
So, what contentious opinions do you hold? I'd rather avoid the kind of thing which ends up being pretty religious with relatively little basis (e.g. brace placing) but examples might include things like "unit testing isn't actually terribly helpful" or "public fields are okay really". The important thing (to me, anyway) is that you've got reasons behind your opinions.
Please present your opinion and reasoning - I would encourage people to vote for opinions which are well-argued and interesting, whether or not you happen to agree with them.
Programmers who don't code in their spare time for fun will never become as good as those that do.
I think even the smartest and most talented people will never become truly good programmers unless they treat it as more than a job. Meaning that they do little projects on the side, or just mess with lots of different languages and ideas in their spare time.
(Note: I'm not saying good programmers do nothing else than programming, but they do more than program from 9 to 5)
The only "best practice" you should be using all the time is "Use Your Brain".
Too many people jumping on too many bandwagons and trying to force methods, patterns, frameworks etc onto things that don't warrant them. Just because something is new, or because someone respected has an opinion, doesn't mean it fits all :)
EDIT:
Just to clarify - I don't think people should ignore best practices, valued opinions etc. Just that people shouldn't just blindly jump on something without thinking about WHY this "thing" is so great, IS it applicable to what I'm doing, and WHAT benefits/drawbacks does it bring?
"Googling it" is okay!
Yes, I know it offends some people out there that their years of intense memorization and/or glorious stacks of programming books are starting to fall by the wayside to a resource that anyone can access within seconds, but you shouldn't hold that against people that use it.
Too often I hear googling answers to problems the result of criticism, and it really is without sense. First of all, it must be conceded that everyone needs materials to reference. You don't know everything and you will need to look things up. Conceding that, does it really matter where you got the information? Does it matter if you looked it up in a book, looked it up on Google, or heard it from a talking frog that you hallucinated? No. A right answer is a right answer.
What is important is that you understand the material, use it as the means to an end of a successful programming solution, and the client/your employer is happy with the results.
(although if you are getting answers from hallucinatory talking frogs, you should probably get some help all the same)
Most comments in code are in fact a pernicious form of code duplication.
We spend most of our time maintaining code written by others (or ourselves) and poor, incorrect, outdated, misleading comments must be near the top of the list of most annoying artifacts in code.
I think eventually many people just blank them out, especially those flowerbox monstrosities.
Much better to concentrate on making the code readable, refactoring as necessary, and minimising idioms and quirkiness.
On the other hand, many courses teach that comments are very nearly more important than the code itself, leading to the this next line adds one to invoiceTotal style of commenting.
XML is highly overrated
I think too many jump onto the XML bandwagon before using their brains...
XML for web stuff is great, as it's designed for it. Otherwise I think some problem definition and design thoughts should preempt any decision to use it.
My 5 cents
Not all programmers are created equal
Quite often managers think that DeveloperA == DeveloperB simply because they have same level of experience and so on. In actual fact, the performance of one developer can be 10x or even 100x that of another.
It's politically risky to talk about it, but sometimes I feel like pointing out that, even though several team members may appear to be of equal skill, it's not always the case. I have even seen cases where lead developers were 'beyond hope' and junior devs did all the actual work - I made sure they got the credit, though. :)
I fail to understand why people think that Java is absolutely the best "first" programming language to be taught in universities.
For one, I believe that first programming language should be such that it highlights the need to learn control flow and variables, not objects and syntax
For another, I believe that people who have not had experience in debugging memory leaks in C / C++ cannot fully appreciate what Java brings to the table.
Also the natural progression should be from "how can I do this" to "how can I find the library which does that" and not the other way round.
If you only know one language, no matter how well you know it, you're not a great programmer.
There seems to be an attitude that says once you're really good at C# or Java or whatever other language you started out learning then that's all you need. I don't believe it- every language I have ever learned has taught me something new about programming that I have been able to bring back into my work with all the others. I think that anyone who restricts themselves to one language will never be as good as they could be.
It also indicates to me a certain lack of inquistiveness and willingness to experiment that doesn't necessarily tally with the qualities I would expect to find in a really good programmer.
Performance does matter.
Print statements are a valid way to debug code
I believe it is perfectly fine to debug your code by littering it with System.out.println (or whatever print statement works for your language). Often, this can be quicker than debugging, and you can compare printed outputs against other runs of the app.
Just make sure to remove the print statements when you go to production (or better, turn them into logging statements)
Your job is to put yourself out of work.
When you're writing software for your employer, any software that you create is to be written in such a way that it can be picked up by any developer and understood with a minimal amount of effort. It is well designed, clearly and consistently written, formatted cleanly, documented where it needs to be, builds daily as expected, checked into the repository, and appropriately versioned.
If you get hit by a bus, laid off, fired, or walk off the job, your employer should be able to replace you on a moment's notice, and the next guy could step into your role, pick up your code and be up and running within a week tops. If he or she can't do that, then you've failed miserably.
Interestingly, I've found that having that goal has made me more valuable to my employers. The more I strive to be disposable, the more valuable I become to them.
1) The Business Apps farce:
I think that the whole "Enterprise" frameworks thing is smoke and mirrors. J2EE, .NET, the majority of the Apache frameworks and most abstractions to manage such things create far more complexity than they solve.
Take any regular Java or .NET ORM, or any supposedly modern MVC framework for either which does "magic" to solve tedious, simple tasks. You end up writing huge amounts of ugly XML boilerplate that is difficult to validate and write quickly. You have massive APIs where half of those are just to integrate the work of the other APIs, interfaces that are impossible to recycle, and abstract classes that are needed only to overcome the inflexibility of Java and C#. We simply don't need most of that.
How about all the different application servers with their own darned descriptor syntax, the overly complex database and groupware products?
The point of this is not that complexity==bad, it's that unnecessary complexity==bad. I've worked in massive enterprise installations where some of it was necessary, but even in most cases a few home-grown scripts and a simple web frontend is all that's needed to solve most use cases.
I'd try to replace all of these enterprisey apps with simple web frameworks, open source DBs, and trivial programming constructs.
2) The n-years-of-experience-required:
Unless you need a consultant or a technician to handle a specific issue related to an application, API or framework, then you don't really need someone with 5 years of experience in that application. What you need is a developer/admin who can read documentation, who has domain knowledge in whatever it is you're doing, and who can learn quickly. If you need to develop in some kind of language, a decent developer will pick it up in less than 2 months. If you need an administrator for X web server, in two days he should have read the man pages and newsgroups and be up to speed. Anything less and that person is not worth what he is paid.
3) The common "computer science" degree curriculum:
The majority of computer science and software engineering degrees are bull. If your first programming language is Java or C#, then you're doing something wrong. If you don't get several courses full of algebra and math, it's wrong. If you don't delve into functional programming, it's incomplete. If you can't apply loop invariants to a trivial for loop, you're not worth your salt as a supposed computer scientist. If you come out with experience in x and y languages and object orientation, it's full of s***. A real computer scientist sees a language in terms of the concepts and syntaxes it uses, and sees programming methodologies as one among many, and has such a good understanding of the underlying philosophies of both that picking new languages, design methods, or specification languages should be trivial.
Getters and Setters are Highly Overused
I've seen millions of people claiming that public fields are evil, so they make them private and provide getters and setters for all of them. I believe this is almost identical to making the fields public, maybe a bit different if you're using threads (but generally is not the case) or if your accessors have business/presentation logic (something 'strange' at least).
I'm not in favor of public fields, but against making a getter/setter (or Property) for everyone of them, and then claiming that doing that is encapsulation or information hiding... ha!
UPDATE:
This answer has raised some controversy in it's comments, so I'll try to clarify it a bit (I'll leave the original untouched since that is what many people upvoted).
First of all: anyone who uses public fields deserves jail time
Now, creating private fields and then using the IDE to automatically generate getters and setters for every one of them is nearly as bad as using public fields.
Many people think:
private fields + public accessors == encapsulation
I say (automatic or not) generation of getter/setter pair for your fields effectively goes against the so called encapsulation you are trying to achieve.
Lastly, let me quote Uncle Bob in this topic (taken from chapter 6 of "Clean Code"):
There is a reason that we keep our
variables private. We don't want
anyone else to depend on them. We want
the freedom to change their type or
implementation on a whim or an
impulse. Why, then, do so many
programmers automatically add getters
and setters to their objects, exposing
their private fields as if they were
public?
UML diagrams are highly overrated
Of course there are useful diagrams e.g. class diagram for the Composite Pattern, but many UML diagrams have absolutely no value.
Opinion: SQL is code. Treat it as such
That is, just like your C#, Java, or other favorite object/procedure language, develop a formatting style that is readable and maintainable.
I hate when I see sloppy free-formatted SQL code. If you scream when you see both styles of curly braces on a page, why or why don't you scream when you see free formatted SQL or SQL that obscures or obfuscates the JOIN condition?
Readability is the most important aspect of your code.
Even more so than correctness. If it's readable, it's easy to fix. It's also easy to optimize, easy to change, easy to understand. And hopefully other developers can learn something from it too.
If you're a developer, you should be able to write code
I did quite a bit of interviewing last year, and for my part of the interview I was supposed to test the way people thought, and how they implemented simple-to-moderate algorithms on a white board. I'd initially started out with questions like:
Given that Pi can be estimated using the function 4 * (1 - 1/3 + 1/5 - 1/7 + ...) with more terms giving greater accuracy, write a function that calculates Pi to an accuracy of 5 decimal places.
It's a problem that should make you think, but shouldn't be out of reach to a seasoned developer (it can be answered in about 10 lines of C#). However, many of our (supposedly pre-screened by the agency) candidates couldn't even begin to answer it, or even explain how they might go about answering it. So after a while I started asking simpler questions like:
Given the area of a circle is given by Pi times the radius squared, write a function to calculate the area of a circle.
Amazingly, more than half the candidates couldn't write this function in any language (I can read most popular languages so I let them use any language of their choice, including pseudo-code). We had "C# developers" who could not write this function in C#.
I was surprised by this. I had always thought that developers should be able to write code. It seems that, nowadays, this is a controversial opinion. Certainly it is amongst interview candidates!
Edit:
There's a lot of discussion in the comments about whether the first question is a good or bad one, and whether you should ask questions as complex as this in an interview. I'm not going to delve into this here (that's a whole new question) apart from to say you're largely missing the point of the post.
Yes, I said people couldn't make any headway with this, but the second question is trivial and many people couldn't make any headway with that one either! Anybody who calls themselves a developer should be able to write the answer to the second one in a few seconds without even thinking. And many can't.
The use of hungarian notation should be punished with death.
That should be controversial enough ;)
Design patterns are hurting good design more than they're helping it.
IMO software design, especially good software design is far too varied to be meaningfully captured in patterns, especially in the small number of patterns people can actually remember - and they're far too abstract for people to really remember more than a handful. So they're not helping much.
And on the other hand, far too many people become enamoured with the concept and try to apply patterns everywhere - usually, in the resulting code you can't find the actual design between all the (completely meaningless) Singletons and Abstract Factories.
Less code is better than more!
If the users say "that's it?", and your work remains invisible, it's done right. Glory can be found elsewhere.
PHP sucks ;-)
The proof is in the pudding.
Unit Testing won't help you write good code
The only reason to have Unit tests is to make sure that code that already works doesn't break. Writing tests first, or writing code to the tests is ridiculous. If you write to the tests before the code, you won't even know what the edge cases are. You could have code that passes the tests but still fails in unforeseen circumstances.
And furthermore, good developers will keep cohesion low, which will make the addition of new code unlikely to cause problems with existing stuff.
In fact, I'll generalize that even further,
Most "Best Practices" in Software Engineering are there to keep bad programmers from doing too much damage.
They're there to hand-hold bad developers and keep them from making dumbass mistakes. Of course, since most developers are bad, this is a good thing, but good developers should get a pass.
Write small methods. It seems that programmers love to write loooong methods where they do multiple different things.
I think that a method should be created wherever you can name one.
It's ok to write garbage code once in a while
Sometimes a quick and dirty piece of garbage code is all that is needed to fulfill a particular task. Patterns, ORMs, SRP, whatever... Throw up a Console or Web App, write some inline sql ( feels good ), and blast out the requirement.
Code == Design
I'm no fan of sophisticated UML diagrams and endless code documentation. In a high level language, your code should be readable and understandable as is. Complex documentation and diagrams aren't really any more user friendly.
Here's an article on the topic of Code as Design.
Software development is just a job
Don't get me wrong, I enjoy software development a lot. I've written a blog for the last few years on the subject. I've spent enough time on here to have >5000 reputation points. And I work in a start-up doing typically 60 hour weeks for much less money than I could get as a contractor because the team is fantastic and the work is interesting.
But in the grand scheme of things, it is just a job.
It ranks in importance below many things such as family, my girlfriend, friends, happiness etc., and below other things I'd rather be doing if I had an unlimited supply of cash such as riding motorbikes, sailing yachts, or snowboarding.
I think sometimes a lot of developers forget that developing is just something that allows us to have the more important things in life (and to have them by doing something we enjoy) rather than being the end goal in itself.
I also think there's nothing wrong with having binaries in source control.. if there is a good reason for it. If I have an assembly I don't have the source for, and might not necessarily be in the same place on each devs machine, then I will usually stick it in a "binaries" directory and reference it in a project using a relative path.
Quite a lot of people seem to think I should be burned at the stake for even mentioning "source control" and "binary" in the same sentence. I even know of places that have strict rules saying you can't add them.
Every developer should be familiar with the basic architecture of modern computers. This also applies to developers who target a virtual machine (maybe even more so, because they have been told time and time again that they don't need to worry themselves with memory management etc.)
Software Architects/Designers are Overrated
As a developer, I hate the idea of Software Architects. They are basically people that no longer code full time, read magazines and articles, and then tell you how to design software. Only people that actually write software full time for a living should be doing that. I don't care if you were the worlds best coder 5 years ago before you became an Architect, your opinion is useless to me.
How's that for controversial?
Edit (to clarify): I think most Software Architects make great Business Analysts (talking with customers, writing requirements, tests, etc), I simply think they have no place in designing software, high level or otherwise.
There is no "one size fits all" approach to development
I'm surprised that this is a controversial opinion, because it seems to me like common sense. However, there are many entries on popular blogs promoting the "one size fits all" approach to development so I think I may actually be in the minority.
Things I've seen being touted as the correct approach for any project - before any information is known about it - are things like the use of Test Driven Development (TDD), Domain Driven Design (DDD), Object-Relational Mapping (ORM), Agile (capital A), Object Orientation (OO), etc. etc. encompassing everything from methodologies to architectures to components. All with nice marketable acronyms, of course.
People even seem to go as far as putting badges on their blogs such as "I'm Test Driven" or similar, as if their strict adherence to a single approach whatever the details of the project project is actually a good thing.
It isn't.
Choosing the correct methodologies and architectures and components, etc., is something that should be done on a per-project basis, and depends not only on the type of project you're working on and its unique requirements, but also the size and ability of the team you're working with.