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• At what point would you drop some of your principles of software development for the sake of more money?

  - by MeshMan

  I'd like to throw this question out there to interestingly see where the medium is. I'm going to admit that in my last 12 months, I picked up TDD and a lot of the Agile values in software development. I was so overwhelmed with how much better my development of software became that I would never drop them out of principle. Until...I was offered a contracting role that doubled my take home pay for the year. The company I joined didn't follow any specific methodology, the team hadn't heard of anything like code smells, SOLID, etc., and I certainly wasn't going to get away with spending time doing TDD if the team had never even seen unit testing in practice. Am I a sell out? No, not completely... Code will always been written "cleanly" (as per Uncle Bob's teachings) and the principles of SOLID will always be applied to the code that I write as they are needed. Testing was dropped for me though, the company couldn't afford to have such a unknown handed to the team who quite frankly, even I did create test frameworks, they would never use/maintain the test framework correctly. Using that as an example, what point would you say a developer should never drop his craftsmanship principles for the sake of money/other benefits to them personally? I understand that this can be a very personal opinion on how concerned one is to their own needs, business needs, and the sake of craftsmanship etc. But one can consider that for example testing can be dropped if the company decided they would rather have a test team, than rather understand unit testing in programming, would that be something you could forgive yourself for like I did? So given that there is something you would drop, there usually should be an equal cost in the business that makes up for what you drop - hopefully, unless of course you are pretty much out for lining your own pockets and not community/social collaborating ;). Double your money, go back to RAD? Or walk on, and look for someone doing Agile, and never look back...

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• Gödel, Escher, Bach - Gödel's string

  - by Brad Urani

  In the book Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter, the author gives us a representation of the precursor to Gödel's string (Gödel's string's uncle) as: ~Ea,a': (I don't have the book in front of me but I think that's right). All that remains to get Gödel's string is to plug the Gödel number for this string into the free variable a''. What I don't understand is how to get the Gödel number for the functions PROOF-PAIR and ARITHMOQUINE. I understand how to write these functions in a programming language like FlooP (from the book) and could even write them myself in C# or Java, but the scheme that Hofstadter defines for Gödel numbering only applies to TNT (which is just his own syntax for natural number theory) and I don't see any way to write a procedure in TNT since it doesn't have any loops, variable assignments etc. Am I missing the point? Perhaps Gödel's string is not something that can actually be printed, but rather a theoretical string that need not actually be defined? I thought it would be neat to write a computer program that actually prints Gödel's string, or Gödel's string encoded by Gödel numbering (yes, I realize it would have a gazillion digits) but it seems like doing so requires some kind of procedural language and a Gödel numbering system for that procedural language that isn't included in the book. Of course once you had that, you could write a program that plugs random numbers into variable "a" and run procedure PROOF-PAIR on it to test for theoromhood of Gödel's string. If you let it run for a trillion years you might find a derivation that proves Gödel's string.

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• Getting that buzz back?

  - by kyndigs

  I have been working in development for a good company for a while now since graduating from university, I really enjoy it and have some great fun in the office and enjoy everything I am doing. But recently I have lost that old buzz, I cant bring myself to code outside of work, a while back I could be outside of work and come up with a nice idea and go away and develop that idea, but I feel that buzz has gone, I still love developing and technology but I just cant find the energy to do it when I am not at work. Has anyone else gone through a phase like this? What did you do to combat it and get that energy and buzz back? Maybe I need a new tehcnology, or a holiday!

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• How do we keep dependent data structures up to date?

  - by Geo

  Suppose you have a parse tree, an abstract syntax tree, and a control flow graph, each one logically derived from the one before. In principle it is easy to construct each graph given the parse tree, but how can we manage the complexity of updating the graphs when the parse tree is modified? We know exactly how the tree has been modified, but how can the change be propagated to the other trees in a way that doesn't become difficult to manage? Naturally the dependent graph can be updated by simply reconstructing it from scratch every time the first graph changes, but then there would be no way of knowing the details of the changes in the dependent graph. I currently have four ways to attempt to solve this problem, but each one has difficulties. Nodes of the dependent tree each observe the relevant nodes of the original tree, updating themselves and the observer lists of original tree nodes as necessary. The conceptual complexity of this can become daunting. Each node of the original tree has a list of the dependent tree nodes that specifically depend upon it, and when the node changes it sets a flag on the dependent nodes to mark them as dirty, including the parents of the dependent nodes all the way down to the root. After each change we run an algorithm that is much like the algorithm for constructing the dependent graph from scratch, but it skips over any clean node and reconstructs each dirty node, keeping track of whether the reconstructed node is actually different from the dirty node. This can also get tricky. We can represent the logical connection between the original graph and the dependent graph as a data structure, like a list of constraints, perhaps designed using a declarative language. When the original graph changes we need only scan the list to discover which constraints are violated and how the dependent tree needs to change to correct the violation, all encoded as data. We can reconstruct the dependent graph from scratch as though there were no existing dependent graph, and then compare the existing graph and the new graph to discover how it has changed. I'm sure this is the easiest way because I know there are algorithms available for detecting differences, but they are all quite computationally expensive and in principle it seems unnecessary so I'm deliberately avoiding this option. What is the right way to deal with these sorts of problems? Surely there must be a design pattern that makes this whole thing almost easy. It would be nice to have a good solution for every problem of this general description. Does this class of problem have a name?

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• Liskov principle: violation by type-hinting

  - by Elias Van Ootegem

  According to the Liskov principle, a construction like the one below is invalid, as it strengthens a pre-condition. I know the example is pointless/nonsense, but when I last asked a question like this, and used a more elaborate code sample, it seemed to distract people too much from the actual question. //Data models abstract class Argument { protected $value = null; public function getValue() { return $this->value; } abstract public function setValue($val); } class Numeric extends Argument { public function setValue($val) { $this->value = $val + 0;//coerce to number return $this; } } //used here: abstract class Output { public function printValue(Argument $arg) { echo $this->format($arg); return $this; } abstract public function format(Argument $arg); } class OutputNumeric extends Output { public function format(Numeric $arg)//<-- VIOLATION! { $format = is_float($arg->getValue()) ? '%.3f' : '%d'; return sprintf($format, $arg->getValue()); } } My question is this: Why would this kind of "violation" be considered harmful? So much so that some languages, like the one I used in this example (PHP), don't even allow this? I'm not allowed to strengthen the type-hint of an abstract method but, by overriding the printValue method, I am allowed to write: class OutputNumeric extends Output { final public function printValue(Numeric $arg) { echo $this->format($arg); } public function format(Argument $arg) { $format = is_float($arg->getValue()) ? '%.3f' : '%d'; return sprintf($format, $arg->getValue()); } } But this would imply repeating myself for each and every child of Output, and makes my objects harder to reuse. I understand why the Liskov principle exists, don't get me wrong, but I find it somewhat difficult to fathom why the signature of an abstract method in an abstract class has to be adhered to so much stricter than a non-abstract method. Could someone explain to me why I'm not allowed to hind at a child class, in a child class? The way I see it, the child class OutputNumeric is a specific use-case of Output, and thus might need a specific instance of Argument, namely Numeric. Is it really so wrong of me to write code like this?

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• Web framework able to handle many concurrent users [closed]

  - by Jonas

  Social networking sites needs to handle many concurrent users e.g. for chat functionality. What web frameworks scales well and are able to handle more than 10.000 concurrent users connected with Comet or WebSockets. The server is a Linux VPS with limited memory, e.g. 1GB-8GB. I have been looking for some Java frameworks but they consume much memory per connection. So I'm looking for other alternatives too. Are there any good frameworks that are able to handle more than 10.000 concurrent users with limited memory resources?

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• Multi-platform Map Application

  - by Mahdi

  I'm working on a web project (PHP, jQuery) which currently using Google Maps powering up the map functionality of the application, however we need to make it multi-platform like you can go to the dashboard and choose one from 5-10 map providers (which Goolge Maps is just one of them) to underlying your map functionality. So, as the application is supposed to show the data on map, almost in every single place we have to deal with the API provided by that specific map provider. Currently we are thinking about revising our modular structure and/or making something like an adapter for each provider to deal with their native syntax but via our standard methods. I wish to have your ideas and your experiences, specially if you ever made an interface for dealing via 2-3 different map providers. That would helps much and I really appreciate that. If you need any further information, just ask me to update the question. Update: As Vicky Chijwani suggested Mapstraction, now I'm also wondering which one is more better (pros & cons), having an adapter implemented on Javascript or PHP?

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• What do I need to develop a PHP extension in lampp?

  - by Fernando Costa

  Actually I'm dealing with a trouble in my system, I have to delivery the system to clients and it was built in PHP, JS, ShellScript and SQL. I would like to encrypt the code or obfuscate it from eyes of others! Then someone from the community told me about build my own PHP extension, it sounds to me as a great idea, since it will not be with the main code of the system. But I have a problem doing this way, if a programmer get in the extensions and find it, all the hard work has gone. Then I'm here to ask again about this matter. What is the best way to hide my Business Logic from third parties? I know that has stuffs like IonCube, Zend Guard, and many others. But I'm looking something that I can build myself. Is PHP extension the right way to follow? Or some Half SaaS system, with dependencies (Business Logic) in a remote server? About the environment OS: Kernel Linux 2.6.37.1-1.2 - LAMPP (Apache 2.2, MySQL 5.5 PHP 5.3.8) In php generally the extension is located at /php/ext/ but in lampp I have no idea where it is, I just found a folder /opt/lampp/lib/php/extensions/ is that right place?

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• What does your Lisp workflow look like?

  - by Duncan Bayne

  I'm learning Lisp at the moment, coming from a language progression that is Locomotive BASIC - Z80 Assembler - Pascal - C - Perl - C# - Ruby. My approach is to simultaneously: write a simple web-scraper using SBCL, QuickLisp, closure-html, and drakma watch the SICP lectures I think this is working well; I'm developing good 'Lisp goggles', in that I can now read Lisp reasonably easily. I'm also getting a feel for how the Lisp ecosystem works, e.g. Quicklisp for dependencies. What I'm really missing, though, is a sense of how a seasoned Lisper actually works. When I'm coding for .NET, I have Visual Studio set up with ReSharper and VisualSVN. I write tests, I implement, I refactor, I commit. Then when I'm done enough of that to complete a story, I write some AUATs. Then I kick off a Release build on TeamCity to push the new functionality out to the customer for testing & hopefully approval. If it's an app that needs an installer, I use either WiX or InnoSetup, obviously building the installer through the CI system. So, my question is: as an experienced Lisper, what does your workflow look like? Do you work mostly in the REPL, or in the editor? How do you do unit tests? Continuous integration? Packaging & deployment? When you sit down at your desk, steaming mug of coffee to one side and a framed photo of John McCarthy to the other, what is it that you do? Currently, I feel like I am getting to grips with Lisp coding, but not Lisp development ...

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• Why is testing MVC Views frowned upon?

  - by Peter Bernier

  I'm currently setting the groundwork for an ASP.Net MVC application and I'm looking into what sort of unit-tests I should be prepared to write. I've seen in multiple places people essentially saying 'don't bother testing your views, there's no logic and it's trivial and will be covered by an integration test'. I don't understand how this has become the accepted wisdom. Integration tests serve an entirely different purpose than unit tests. If I break something, I don't want to know a half-hour later when my integration tests break, I want to know immediately. Sample Scenario : Lets say we're dealing with a standard CRUD app with a Customer entity. The customer has a name and an address. At each level of testing, I want to verify that the Customer retrieval logic gets both the name and the address properly. To unit-test the repository, I write an integration test to hit the database. To unit-test the business rules, I mock out the repository, feed the business rules appropriate data, and verify my expected results are returned. What I'd like to do : To unit-test the UI, I mock out the business rules, setup my expected customer instance, render the view, and verify that the view contains the appropriate values for the instance I specified. What I'm stuck doing : To unit-test the repository, I write an integration test, setup an appropriate login, create the required data in the database, open a browser, navigate to the customer, and verify the resulting page contains the appropriate values for the instance I specified. I realize that there is overlap between the two scenarios discussed above, but the key difference it time and effort required to setup and execute the tests. If I (or another dev) removes the address field from the view, I don't want to wait for the integration test to discover this. I want is discovered and flagged in a unit-test that gets multiple times daily. I get the feeling that I'm just not grasping some key concept. Can someone explain why wanting immediate test feedback on the validity of an MVC view is a bad thing? (or if not bad, then not the expected way to get said feedback)

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• Quantifying the value of refactoring in commercial terms

  - by Myles McDonnell

  Here is the classic scenario; Dev team build a prototype. Business mgmt like it and put it into production. Dev team now have to continue to deliver new features whilst at the same time pay the technical debt accrued when the code base was a prototype. My question is this (forgive me, it's rather open ended); how can the value of the refactoring work be quantified in commercial terms? As developers we can clearly understand and communicate the value in technical terms, such a the removal of code duplication, the simplification of an object model and so on. But this means little to an executive focussed on the commercial elements. What will mean something to this executive is the dev. team being able to deliver requirements at faster velocity. Just making this statement without any metrics that clearly quantify return on investment (increased velocity in return for resource allocated to refactoring) carries little weight. I'm interested to hear from anyone who has had experience, positive or negative, in relation to the above. ----------------- EDIT ---------------- Thanks for the responses so far, all of which I think are good. What I want to develop is a metric that proves (or disproves!) all of these statements. A report that ties velocity to refactoring and shows a positive effect.

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• Web Developer Portfolio - Role Definition

  - by GSTAR

  I'm just putting together a portfolio that lists all the websites I have developed / worked on during the past year. Now this has become quite a long list - simply because 60% of the websites I have listed are ones where I have developed certain sections of the site, or maybe re-developed a certain section of an existing site - but not actually developed the whole site. So basically you could say I made a 20-50% contribution on those particular sites. I don't want to give the false impression to a potential employer that I have actually fully developed all the sites listed on my portfolio. Therefore I am after a neat way to indicate this fact. On the websites that I have fully developed, I have put a small label next to the name which reads "Lead Developer". What would be the equivalent label to put on the sites I have partially developed, or projects where I have been amongst multiple people developing? I suppose what I'm asking is, how would you define, in 2-3 words a non-lead developer role within a project?

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• Is an 'if password == XXXXXXX' enough for minimum security?

  - by Morgan Herlocker

  If I create a login for an app that has middle to low security risk (in other words, its not a banking app or anything), is it acceptable for me to verify a password entered by the user by just saying something like: if(enteredPassword == verifiedPassword) SendToRestrictedArea(); else DisplayPasswordUnknownMessage(); It seems to easy to be effective, but I certainly would not mind if that was all that was required. Is a simple check on username/password combo enough? Update: The particular project happens to be a web service, the verification is entirely server side, and it is not open-source. Does the domain change how you would deal with this?

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• What are the arguments against parsing the Cthulhu way?

  - by smarmy53

  I have been assigned the task of implementing a Domain Specific Language for a tool that may become quite important for the company. The language is simple but not trivial, it already allows nested loops, string concatenation, etc. and it is practically sure that other constructs will be added as the project advances. I know by experience that writing a lexer/parser by hand -unless the grammar is trivial- is a time consuming and error prone process. So I was left with two options: a parser generator à la yacc or a combinator library like Parsec. The former was good as well but I picked the latter for various reasons, and implemented the solution in a functional language. The result is pretty spectacular to my eyes, the code is very concise, elegant and readable/fluent. I concede it may look a bit weird if you never programmed in anything other than java/c#, but then this would be true of anything not written in java/c#. At some point however, I've been literally attacked by a co-worker. After a quick glance at my screen he declared that the code is uncomprehensible and that I should not reinvent parsing but just use a stack and String.Split like everybody does. He made a lot of noise, and I could not convince him, partially because I've been taken by surprise and had no clear explanation, partially because his opinion was immutable (no pun intended). I even offered to explain him the language, but to no avail. I'm positive the discussion is going to re-surface in front of management, so I'm preparing some solid arguments. These are the first few reasons that come to my mind to avoid a String.Split-based solution: you need lot of ifs to handle special cases and things quickly spiral out of control lots of hardcoded array indexes makes maintenance painful extremely difficult to handle things like a function call as a method argument (ex. add( (add a, b), c) very difficult to provide meaningful error messages in case of syntax errors (very likely to happen) I'm all for simplicity, clarity and avoiding unnecessary smart-cryptic stuff, but I also believe it's a mistake to dumb down every part of the codebase so that even a burger flipper can understand it. It's the same argument I hear for not using interfaces, not adopting separation of concerns, copying-pasting code around, etc. A minimum of technical competence and willingness to learn is required to work on a software project after all. (I won't use this argument as it will probably sound offensive, and starting a war is not going to help anybody) What are your favorite arguments against parsing the Cthulhu way?* *of course if you can convince me he's right I'll be perfectly happy as well

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• Need help in using hadoop in a Spring-Hibernate-JPA based web application [closed]

  - by John Varghese

  Possible Duplicate: Need help in using hadoop framework in a Spring-Hibernate-JPA based web application We are developing a Spring-Hibernate-JPA based web application which uses MySql as the database for storage and retrieval. We need to store and compute huge amounts of data, for that we need to use hadoop framework. How hadoop framework can be used in our web application to store and compute huge amounts of data?

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• How does one handle an incorrect resource file?

  - by AedonEtLIRA

  I'm starting the parser that will handle one of the key features of my app and realizing exactly who easy it would be for me to screw up a resource file that is provided to the application. For example, a simple resource that I provide to my app is a JSON file that contains an entity layout (name, fascia, location etc...). It would be easy for me to leave out the name of the entity or misspell the JSON key. Obviously catastrophic failures during parsing are to be handled in a try/catch, but how would subtle failures (such as a dyslexic spelling of name) be handled?

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• Looking for a light weight note program.

  - by Erin

  This might belongs on superuser but for me it's part of programming so i will ask it here. I find I use notepad to keep chunks of data that are important but not important enough to keep in my head. The one problem with this is I end up with a lot of files on my desktop that I don't know what they are for, or I don't save the file and my computer gets rebooted for some reason. So that big ramble leads to the question. I am looking for a note taking system that is light weight and easy to manage. I would rather it not be a huge application like onenote but if that is what you are using and is is working well for you could you explain how you are doing it? Thanks Erin.

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• Exclusive use of a Jini server during long-running call

  - by Matthew Flint

  I'm trying to use Jini, in a "Masters/Workers" arrangement, but the Worker jobs may be long running. In addition, each worker needs to have exclusive access to a singleton resource on that machine. As it stands, if a Worker receives another request while a previous request is running, then the new request is accepted and executed in a second thread. Are there any best-practices to ensure that a Worker accepts no further jobs until the current job is complete? Things I've considered: synchronize the job on the server, with a lock on the singleton resource. This would work, but is far from ideal. A call from a Master would block until the current Worker thread completes, even if other Workers become free in the meantime unregister the Worker from the registry while the job is running, then re-register when it completes. Might work OK, but something doesn't smell right with this idea... Of course, I'm quite happy to be told that there are more appropriate technologies than Jini... but I wouldn't want anything too heavyweight, like rolling out EJB containers all over the place.

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• How to achieve a loosely coupled REST API but with a defined and well understood contract?

  - by BestPractices

  I am new to REST and am struggling to understand how one would properly design a REST system to both allow for loose coupling but at the same time allow a consumer of a REST API to understand the API. If, in my client code, I issue a GET request for a resource and get back XML, how do I know what to do with that xml? e.g. if it contains <fname>John</fname><lname>Smith</lname> how do I know that these refer to the concept of "first name", "last name"? Is it up to the person writing the REST API to define in documentation some place what each of the XML fields mean? What if producer of the API wants to change the implementation to be <firstname> instead of <fname>? How do they do this and notify their consumers that this change occurred? Or do the consumers just encounter the error and then look at the payload and figure out on their own that it changed? I've read in REST in Practice that using a WADL tool to create a client implementation based on the WADL (and hide the fact that you're doing a distributed call) is an "anti-pattern". But I was planning to do this-- at least then I would have a statically typed API call that, if it changed, I would know at compile time and not at run time. Why is this a bad thing to generate client code based on a WADL? And how do I know what to do with the links that returned in the response of a POST to a REST API? What defines this contract and gives true meaning to what each link will do? Please help! I dont understand how to go from statically-typed or even SOAP/RPC to REST!

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• DDD and Value Objects. Are mutable Value Objects a good candidate for Non Aggr. Root Entity?

  - by Tony

  Here is a little problem Have an entity, with a value object. Not a problem. I replace a value object for a new one, then nhibernate inserts the new value and orphan the old one, then deletes it. Ok, that's a problem. Insured is my entity in my domain. He has a collection of Addresses (value objects). One of the addresses is the MailingAddress. When we want to update the mailing address, let's say zipcode was wrong, following Mr. Evans doctrine, we must replace the old object for a new one since it's immutable (a value object right?). But we don't want to delete the row thou, because that address's PK is a FK in a MailingHistory table. So, following Mr. Evans doctrine, we are pretty much screwed here. Unless i make my addressses Entities, so i don't have to "replace" it, and simply update its zipcode member, like the old good days. What would you suggest me in this case? The way i see it, ValueObjects are only useful when you want to encapsulate a group of database table's columns (component in nhibernate). Everything that has a persistence id in the database, is better off to make it an Entity (not necessarily an aggregate root) so you can update its members without recreating the whole object graph, specially if that's a deep-nested object. Do you concur? Is it allowed by Mr. Evans to have a mutable value object? Or is a mutable value object a candidate for an Entity? Thanks

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• Version Changes: How considerable are the compatibility issues in project?

  - by Aditya P

  For example if we consider ActionScript2.0(based on Objects but programming does not implement much OOP ) vs 3.0(highly OOP) its like a whole new scripting language in the sense of approach, programming style,features you get the idea. In PHP we can see current versions going from 3-5. brief version changes Question :Developers who work on PHP is it easy to migrate from version to version? Question :Are there any extensive compatibility issues, forward or backward? Question :Does your project stick to a particular version till the end ? Question :Does the programming style ,approach change from version to version? Question :If you had to get started on PHP to contribute to a project built earlier versions, would learning the latest version be counterproductive towards this aim? Some related topics i had come across on SE How should I be keeping track of php script version/changes? What is happening to PHP 6? It would be Really helpful in understanding if you could answer this topic directly to the questions put forth.

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• How is this number calculated?

  - by Hamid

  I have numbers; A == 0x20000000 B == 18 C == (B/10) D == 0x20000004 == (A + C) A and D are in hex, but I'm not sure what the assumed numeric bases of the others are (although I'd assume base 10 since they don't explicitly state a base. It may or may not be relevant but I'm dealing with memory addresses, A and D are pointers. The part I'm failing to understand is how 18/10 gives me 0x4. Edit: Code for clarity: *address1 (pointer is to address: 0x20000000) printf("Test1: %p\n", address1); printf("Test2: %p\n", address1+(18/10)); printf("Test3: %p\n", address1+(21/10)); Output: Test1: 0x20000000 Test2: 0x20000004 Test3: 0x20000008

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• API Design Techniques

  - by Dehumanizer

  Is it right or more beautiful to name the functions with an prefix, like in Qt? Or using "many" namespaces, but 'normal' names for functions? For example, slOpenFile(); //"sl" means "some lib" vs some_lib::file_functions::openFile(); UPD: I've read somewhere that the first variant(using some prefix) is better, because the API users can perform 'fast' search among the documentation and in the Internet. E.g. by typing the magic prefix search engine starts to advice the exact functions. Is it enough to use the first variant?

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• Do certain corporations hold more weight on a resume?

  - by Ryan

  Would a developer/tester position at Google, Apple, Microsoft, etc. (any large tech. company of which most people have heard) be more valuable on a resume than working as a developer/tester somewhere where tech. isn't the main objective (shipping company, restaurant chain, insurance company, etc.)? Let's say you have two offers, and you only plan to stay with whichever company for 5 years, before trying to get a better position at a different company. One at Google that has a starting salary of $60,000, and one at some insurance company that has a starting salary of $80,000. I guess what I'm trying to say is... with university's, if someone graduates from MIT or Carnegie Mellon, they can pretty much get a job anywhere. Does someone seem more valuable after having worked at a company like Google, Apple, Microsoft, etc.? In other words, would taking the lower paying job be better in the long run since it's at Google, or would it be better to take the higher paying job at the insurance company?

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• Class instance clustering in object reference graph for multi-entries serialization

  - by Juh_

  My question is on the best way to cluster a graph of class instances (i.e. objects, the graph nodes) linked by object references (the -directed- edges of the graph) around specifically marked objects. To explain better my question, let me explain my motivation: I currently use a moderately complex system to serialize the data used in my projects: "marked" objects have a specific attributes which stores a "saving entry": the path to an associated file on disc (but it could be done for any storage type providing the suitable interface) Those object can then be serialized automatically (eg: obj.save()) The serialization of a marked object 'a' contains implicitly all objects 'b' for which 'a' has a reference to, directly s.t: a.b = b, or indirectly s.t.: a.c.b = b for some object 'c' This is very simple and basically define specific storage entries to specific objects. I have then "container" type objects that: can be serialized similarly (in fact their are or can-be "marked") they don't serialize in their storage entries the "marked" objects (with direct reference): if a and a.b are both marked, a.save() calls b.save() and stores a.b = storage_entry(b) So, if I serialize 'a', it will serialize automatically all objects that can be reached from 'a' through the object reference graph, possibly in multiples entries. That is what I want, and is usually provides the functionalities I need. However, it is very ad-hoc and there are some structural limitations to this approach: the multi-entry saving can only works through direct connections in "container" objects, and there are situations with undefined behavior such as if two "marked" objects 'a'and 'b' both have a reference to an unmarked object 'c'. In this case my system will stores 'c' in both 'a' and 'b' making an implicit copy which not only double the storage size, but also change the object reference graph after re-loading. I am thinking of generalizing the process. Apart for the practical questions on implementation (I am coding in python, and use Pickle to serialize my objects), there is a general question on the way to attach (cluster) unmarked objects to marked ones. So, my questions are: What are the important issues that should be considered? Basically why not just use any graph parsing algorithm with the "attach to last marked node" behavior. Is there any work done on this problem, practical or theoretical, that I should be aware of? Note: I added the tag graph-database because I think the answer might come from that fields, even if the question is not.

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