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• Drag and drop in as3 on specific path (ex bezier curve)

  - by abinop

  I need to implement a drag and drop functionality, where I can define and constraint the route of the draggable object. Like in http://www.kirupa.com/forum/showthread.php?t=330302 , only that i have the paths designed and not calculated by a math function. So, in fact, as mouse moves I need to tell the object to follow the custom path/movieclip.

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• F# vs Haskell vs Lisp - which language to learn?

  - by empi

  I've heard a lot about functional programming languages and I'm willing to learn one. I guess it will be mostly for fun, however, I hope it will improve my programming skills. I have mostly C#/.NET background, so my first choice is to learn F# (because of .NET and familiarity with Visual Studio). On the on other hand, I wonder if F# has features like Lisp macros or Haskell higher order functions. Could you compare F#, Haskell and Lisp? Which one will be the language of your choice?

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• X.509 Certificate validation with Java and Bouncycastle

  - by Rob

  Hi, through the bouncycastle wiki page I was able to understand how to create a X.509 root certificate and a certification request, but I do not quite understand how to proceed concept- and programming wise after that. Lets assume party A does a cert request and gets his client certificate from the CA. How can some party B validate A's certificate? What kind of certificate does A need? A root certificate? A 'normal' client certificate? And how does the validation work on programming level, if we assume that A has successfully send his certificate in DER or PEM format to B? Any help is much appreciated. Best Regards, Rob

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• What is in your Mathematica tool bag?

  - by Timo

  We all know that Mathematica is great, but it also often lacks critical functionality. What kind of external packages / tools / resources do you use with Mathematica? I'll edit (and invite anyone else to do so too) this main post to include resources which are focused on general applicability in scientific research and which as many people as possible will find useful. Feel free to contribute anything, even small code snippets (as I did below for a timing routine). Also, undocumented and useful features in Mathematica 7 and beyond you found yourself, or dug up from some paper/site are most welcome. Please include a short description or comment on why something is great or what utility it provides. If you link to books on Amazon with affiliate links please mention it, e.g., by putting your name after the link. Packages: LevelScheme is a package that greatly expands Mathematica's capability to produce good looking plots. I use it if not for anything else then for the much, much improved control over frame/axes ticks. David Park's Presentation Package ($50 - no charge for updates) Tools: MASH is Daniel Reeves's excellent perl script essentially providing scripting support for Mathematica 7. (This is finally built in as of Mathematica 8 with the -script option.) Resources: Wolfram's own repository MathSource has a lot of useful if narrow notebooks for various applications. Also check out the other sections such as Current Documentation, Courseware for lectures, and Demos for, well, demos. Books: Mathematica programming: an advanced introduction by Leonid Shifrin (web, pdf) is a must read if you want to do anything more than For loops in Mathematica. Quantum Methods with Mathematica by James F. Feagin (amazon) The Mathematica Book by Stephen Wolfram (amazon) (web) Schaum's Outline (amazon) Mathematica in Action by Stan Wagon (amazon) - 600 pages of neat examples and goes up to Mathematica version 7. Visualization techniques are especially good, you can see some of them on the author's Demonstrations Page. Mathematica Programming Fundamentals by Richard Gaylord (pdf) - A good concise introduction to most of what you need to know about Mathematica programming. Undocumented (or scarcely documented) Features: How to customize Mathematica keyboard shortcuts. See this question. How to inspect patterns and functions used by Mathematica's own functions. See this answer How to achieve Consistent size for GraphPlots in Mathematica? See this question.

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• subsonic.migrations and Oracle XE

  - by andrecarlucci

  Hello, Probably I'm doing something wrong but here it goes: I'm trying to create a database using subsonic.migrations in an OracleXE version 10.2.0.1.0. I have ODP v 10.2.0.2.20 installed. This is my app.config: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="SubSonicService" type="SubSonic.SubSonicSection, SubSonic" requirePermission="false"/> </configSections> <connectionStrings> <add name="test" connectionString="Data Source=XE; User Id=test; Password=test;"/> </connectionStrings> <SubSonicService defaultProvider="test"> <providers> <clear/> <add name="test" type="SubSonic.OracleDataProvider, SubSonic" connectionStringName="test" generatedNamespace="testdb"/> </providers> </SubSonicService> </configuration> And that's my first migration: public class Migration001_Init : Migration { public override void Up() { //Create the records table TableSchema.Table records = CreateTable("asdf"); records.AddColumn("RecordName"); } public override void Down() { DropTable("asdf"); } } When I run the sonic.exe, I get this exception: Setting ConfigPath: 'App.config' Building configuration from D:\Users\carlucci\Documents\Visual Studio 2008\Projects\Wum\Wum.Migration\App.config Adding connection to test ERROR: Trying to execute migrate Error Message: System.Data.OracleClient.OracleException: ORA-02253: especifica‡Æo de restri‡Æo nÆo permitida aqui at System.Data.OracleClient.OracleConnection.CheckError(OciErrorHandle errorHandle, Int32 rc) at System.Data.OracleClient.OracleCommand.Execute(OciStatementHandle statementHandle, CommandBehavior behavior, Boolean needRowid, OciRowidDescriptor& rowidDescriptor, ArrayList& resultParameterOrdinals) at System.Data.OracleClient.OracleCommand.ExecuteNonQueryInternal(Boolean needRowid, OciRowidDescriptor& rowidDescriptor) at System.Data.OracleClient.OracleCommand.ExecuteNonQuery() at SubSonic.OracleDataProvider.ExecuteQuery(QueryCommand qry) in D:\@SubSonic\SubSonic\SubSonic\DataProviders\OracleDataProvider.cs:line 350 at SubSonic.DataService.ExecuteQuery(QueryCommand cmd) in D:\@SubSonic\SubSonic\SubSonic\DataProviders\DataService.cs:line 544 at SubSonic.Migrations.Migrator.CreateSchemaInfo(String providerName) in D:\@SubSonic\SubSonic\SubSonic.Migrations\Migrator.cs:line 249 at SubSonic.Migrations.Migrator.GetCurrentVersion(String providerName) in D:\@SubSonic\SubSonic\SubSonic.Migrations\Migrator.cs:line 232 at SubSonic.Migrations.Migrator.Migrate(String providerName, String migrationDirectory, Nullable`1 toVersion) in D:\@SubSonic\SubSonic\SubSonic.Migrations\Migrator.cs:line 50 at SubSonic.SubCommander.Program.Migrate() in D:\@SubSonic\SubSonic\SubCommander\Program.cs:line 264 at SubSonic.SubCommander.Program.Main(String[] args) in D:\@SubSonic\SubSonic\SubCommander\Program.cs:line 90 Execution Time: 379ms What am I doing wrong? Thanks a lot for any help :) Andre Carlucci UPDATE: As pointed by Anton, the problem is the subsonic OracleSqlGenerator. It is trying to create the schema table using this sql: CREATE TABLE SubSonicSchemaInfo ( version int NOT NULL CONSTRAINT DF_SubSonicSchemaInfo_version DEFAULT (0) ) Which doesn't work on oracle. The correct sql would be: CREATE TABLE SubSonicSchemaInfo ( version int DEFAULT (0), constraint DF_SubSonicSchemaInfo_version primary key (version) ) The funny thing is that since this is the very first sql executed by subsonic migrations, NOBODY EVER TESTED it on oracle.

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• What are the best Google Tech Talks?

  - by Nathaniel Flath

  What are the most interesting programming-related Google Tech Talks?

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• What are modern and old compilers written in?

  - by ulum

  As a compiler, other than an interpreter, only needs to translate the input and not run it the performance of itself should be not that problematic as with an interpreter. Therefore, you wouldn't write an interpreter in, let's say Ruby or PHP because it would be far too slow. However, what about compilers? If you would write a compiler in a scripting language maybe even featuring rapid development you could possibly cut the source code and initial development time by halv, at least I think so. To be sure: With scripting language I mean interpreted languages having typical features that make programming faster, easier and more enjoyable for the programmer, usually at least. Examples: PHP, Ruby, Python, maybe JavaScript though that may be an odd choice for a compiler What are compilers normally written in? As I suppose you will respond with something low-level like C, C++ or even Assembler, why? Are there compilers written in scripting languages? What are the (dis)advantages of using low or high level programming languages for compiler writing?

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• Oracle Trigger to persist value

  - by Jose Jose

  I have a column that I need to be able to guarantee never gets set to anything other than "N" - I thought a trigger would be the perfect solution for this, but I can't seem to figure out how to make it so that anytime the column gets set to something other than "N" I reset it back to "N" Any pointers? EDIT: I wouldn't want to do a constraint because the application that will potentially change it to Y is outside of my control and I don't want it to be getting errors when it sets it to Y, I just want to passively set it back to N without fanfare.

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• Opinions on sensor / reading / alert database design

  - by Mark

  I've asked a few questions lately regarding database design, probably too many ;-) However I beleive I'm slowly getting to the heart of the matter with my design and am slowly boiling it down. I'm still wrestling with a couple of decisions regarding how "alerts" are stored in the database. In this system, an alert is an entity that must be acknowledged, acted upon, etc. Initially I related readings to alerts like this (very cut down) : - [Location] LocationId [Sensor] SensorId LocationId UpperLimitValue LowerLimitValue [SensorReading] SensorReadingId Value Status Timestamp [SensorAlert] SensorAlertId [SensorAlertReading] SensorAlertId SensorReadingId The last table is associating readings with the alert, because it is the reading that dictate that the sensor is in alert or not. The problem with this design is that it allows readings from many sensors to be associated with a single alert - whereas each alert is for a single sensor only and should only have readings for that sensor associated with it (should I be bothered that the DB allows this though?). I thought to simplify things, why even bother with the SensorAlertReading table? Instead I could do this: [Location] LocationId [Sensor] SensorId LocationId [SensorReading] SensorReadingId SensorId Value Status Timestamp [SensorAlert] SensorAlertId SensorId Timestamp [SensorAlertEnd] SensorAlertId Timestamp Basically I'm not associating readings with the alert now - instead I just know that an alert was active between a start and end time for a particular sensor, and if I want to look up the readings for that alert I can do. Obviously the downside is I no longer have any constraint stopping me deleting readings that occurred during the alert, but I'm not sure that the constraint is neccessary. Now looking in from the outside as a developer / DBA, would that make you want to be sick or does it seem reasonable? Is there perhaps another way of doing this that I may be missing? Thanks. EDIT: Here's another idea - it works in a different way. It stores each sensor state change, going from normal to alert in a table, and then readings are simply associated with a particular state. This seems to solve all the problems - what d'ya think? (the only thing I'm not sure about is calling the table "SensorState", I can't help think there's a better name (maybe SensorReadingGroup?) : - [Location] LocationId [Sensor] SensorId LocationId [SensorState] SensorStateId SensorId Timestamp Status IsInAlert [SensorReading] SensorReadingId SensorStateId Value Timestamp There must be an elegant solution to this!

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• Is there anything RAD comparable to VCL?

  - by mawg

  After years in embedded programming, I have to develop a Windows app. I dug out my old C++ Builder and Delphi. These are great and the latest version costs over $1k, so I won't be going there. What I prarticularly like is the VCL (visual component library) which let's me code my own components and share them with others, plus the thousands of existing 3rd party components. I noticed that there is now also a RAD PHP from Borland too. I realzie that MSVC, QT, NetBeans, etc are good enough IDEs for RAD, BUT does anything offer the ease of the Borland products for developing additional components - and does anything else have thousands to choose from? PC based? Cross-platform is good. Browser based? Free is always good ;-) I don't particularly care about the programming language.

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• how to convert byte value into int in objective-c

  - by suse

  Hello, Please tell me how to convert bytes to NSInteger/int in objective-c in iPhone programming?

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• Web Service to connect to an API and get the response back from the API

  - by Scarlette_June

  This is a general Programming question I'm new to Java Web services programming using Apache Axis and JAX-RPC. We need to build 2 components,a App engine (Shopping cart, Payment Gateway integration etc..) and a UI Control Panel over an existing API. The API understands only XML.How we must communicate with the API? link text We have been asked to write a Web Service to establish the communication. Please provide the steps and a Code example/snippet on how to connect to an existing API through a Webservice and get the response back from the API to the calling Webservice. John,I hope I have been able to explain my query.If you have ideas on how to communicate with the API to get the desired result to the user,Please let us know. We have just started our careers in technology a year back post our graduation and this project is our very first Java EE project.

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• Multiple Columns as Primary keys

  - by rockbala

  CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255), CONSTRAINT pk_PersonID PRIMARY KEY (P_Id,LastName) ) The above example is taken from w3schools. From the above example, my understanding is that both P_Id, LastName together represents a Primary Key for the table Persons, correct ? Another question is why would some one want to use multiple columns as Primary keys instead of a single column ? How many such columns can be used in together as Primary key in a given table ? Thanks Balaji S

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• Concrete Types or Interfaces for return types?

  - by SDReyes

  Today I came to a fundamental paradox of the object programming style, concrete types or interfaces. Whats the better election for a method's return type: a concrete type or an interface? In most cases, I tend to use concrete types as the return type for methods. because I believe that an concrete type is more flexible for further use and exposes more functionality. The dark side of this: Coupling. The angelic one: A concrete type contains per-se the interface you would going to return initially, and extra functionality. What's your thumb's rule? Is there any programming principle for this? BONUS: This is an example of what I mean http://stackoverflow.com/questions/491375/readonlycollection-or-ienumerable-for-exposing-member-collections

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• WebApps tendency

  - by Narek

  There is a strong tendency of making web apps and even seems that very soon a lot of features will be available online so that for every day use people will have all necessary software free online and they will not need to install any software locally. Only specific (professional) tools that usually people don’t use at home will not be available as a web app. So my question, how do you imagine selling software that was necessary for everyday use and was not free (seems they can't make money any more by selling their product – no need of those products). And what disadvantages have web apps, that is to say, what is bad to use software online compared with having the same software locally (please list)? Please do not consider this question not connected with programming, as I would like to have a little statistics from professional programmers who are aware from nowday’s tendency of software and programming. Thanks.

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• Hardware Lossless Compression for Hard Drives?

  - by GeoffreyF67

  I happened across this article about hardware based hard drive encryption and realized that not only would this give a great way to protect your data but it would also speed up the applications that we use to encrypt that data. This lead me to wonder... Would it be possible to do the same thing for compression so that all of the data is compressed or uncompressed appropriately as it is read and written to the drive? I haven't done any firmware programming in quite some time so I'm not even sure this is technically possible. If it were, however, it could probably give quite a bit more storage space to folks. What are the pros and cons of programming such an approach to be used in the firmware? G-Man

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• Django unique_together error and validation

  - by zubinmehta

  class Votes(models.Model): field1 = models.ForeignKey(Blah1) field2 = models.ForeignKey(Blah2) class Meta: unique_together = (("field1","field2"),) I am using this code as one of my models. Now i wanted to know two things: 1. It doesn't show any error and it saved an entry which wasn't unique together; So is the piece of code correct? 2. How can the unique_together constraint be be validated?

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• convert a number to the shortest possible character string while retaining uniqueness

  - by alumb

  I have a list of digits, say "123456", and I need to map it to a string, any string. The only constraint on the map functions are: each list of digits must map to a unique character string (this means the string can be arbitrarily long) character string can only contain 0-9, a-z, A-Z What map function would produce the shortest strings? Solutions in JavaScript are preferred. note: Clearly the simplest solution is to use the original list of digits, so make sure you solution does better than that.

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• Web Safe Area (optimal resolution) for web app design

  - by M.A.X

  I'm in the process of designing a new web app and I'm wondering for what 'web safe area' should I optimize the app layout and design. I did some investigation and thinking on my own but wanted to share this to see what the general opinion is. Here is what I found: Optimal Display Resolution: w3schools web stats seems to be the most referenced source (however they state that these are results from their site and is biased towards tech savvy users) http://www.w3counter.com/globalstats.php (aggregate data from something like 15,000 different sites that use their tracking services) StatCounter Global Stats Display Resolution (Stats are based on aggregate data collected by StatCounter on a sample exceeding 15 billion pageviews per month collected from across the StatCounter network of more than 3 million websites) NetMarketShare Screen Resolutions (marketshare.hitslink.com) (a web analytics consulting firm, they get data from browsers of site visitors to their on-demand network of live stats customers. The data is compiled from approximately 160 million visitors per month) Display Resolution Summary: There is a bit of variation between the above sources but in general as of Jan 2011 looks like 1024x768 is about 20%, while ~85% have a higher resolution of at least 1280x768 (1280x800 is the most common of these with 15-20% of total web, depending on the source; 1280x1024 and 1366x768 follow behind with 9-14% of the share). My guess would be that the higher resolution values will be even more common if we filter on North America, and even higher if we filter on N.American corporate users (unfortunately I couldn't find any free geographically filtered statistics). Another point to note is that the 1024x768 desktop user population is likely lower than the aforementioned 20%, seeing as the iPad (1024x768 native display) is likely propping up those number. My recommendation would be to optimize around the 1280x768 constraint (*note: 1280x768 is actually a relatively rare resolution, but I think it's a valid constraint range considering that 1366x768 is relatively common and 1280 is the most common horizontal resolution). Browser + OS Constraints: To further add to the constraints we have to subtract the space taken up by the browser (assuming IE, which is the most space consuming) and the OS (assuming WinXP-Win7): Win7 has the biggest taskbar footprint at a height of 40px (XP's and Vista's is 30px) The default IE8 view uses up 25px at the bottom of the screen with the status bar and a further 120px at the top of the screen with the windows title bar and the browser UI (assuming the default 'favorites' toolbar is present, it would instead be 91px without the favorites toolbar). Assuming no scrollbar, we also loose a total of 4px horizontally for the window outline. This means that we are left with 583px of vertical space and 1276px of horizontal. In other words, a Web Safe Area of 1276 x 583 Is this a correct line of thinking? I tried to Google some design best practices but most still talk about designing around 1024x768 which seems to be quickly disappearing. Any help on this would be greatly appreciated! Thanks.

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• error in mysql syntax

  - by fusion

  while executing the following query, i get an error that there's an error in the syntax near line 9. since i'm using mysql workbench, i can't really figure out what could be wrong: CREATE TABLE IF NOT EXISTS `proquotes`.`thquotes` ( `idQuotes` INT NOT NULL AUTO_INCREMENT , `vAuthorID` VARCHAR(8) CHARACTER SET 'utf8' NOT NULL , `vAuthor` VARCHAR(45) CHARACTER SET 'utf8' NOT NULL , `cQuotes` MEDIUMTEXT CHARACTER SET 'utf8' NOT NULL , `cArabic` MEDIUMTEXT CHARACTER SET 'utf8' NOT NULL , `vReference` VARCHAR(100) CHARACTER SET 'utf8' NOT NULL , PRIMARY KEY (`idQuotes`) , INDEX `vAuthorID` () , CONSTRAINT `vAuthorID` FOREIGN KEY () REFERENCES `proquotes`.`author_info` () ON DELETE NO ACTION ON UPDATE NO ACTION) DEFAULT CHARACTER SET = utf8;

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• GOTO still considered harmful?

  - by Kyle Cronin

  Everyone is aware of Dijkstra's Letters to the editor: go to statement considered harmful (also here .html transcript and here .pdf) and there has been a formidable push since that time to eschew the goto statement whenever possible. While it's possible to use goto to produce unmaintainable, sprawling code, it nevertheless remains in modern programming languages. Even the advanced continuation control structure in Scheme can be described as a sophisticated goto. What circumstances warrant the use of goto? When is it best to avoid? As a followup question: C provides a pair of functions, setjmp and longjmp, that provide the ability to goto not just within the current stack frame but within any of the calling frames. Should these be considered as dangerous as goto? More dangerous? Dijkstra himself regretted that title, of which he was not responsible for. At the end of EWD1308 (also here .pdf) he wrote: Finally a short story for the record. In 1968, the Communications of the ACM published a text of mine under the title "The goto statement considered harmful", which in later years would be most frequently referenced, regrettably, however, often by authors who had seen no more of it than its title, which became a cornerstone of my fame by becoming a template: we would see all sorts of articles under the title "X considered harmful" for almost any X, including one titled "Dijkstra considered harmful". But what had happened? I had submitted a paper under the title "A case against the goto statement", which, in order to speed up its publication, the editor had changed into a "letter to the Editor", and in the process he had given it a new title of his own invention! The editor was Niklaus Wirth. A well thought out classic paper about this topic, to be matched to that of Dijkstra, is Structured Programming with go to Statements (also here .pdf), by Donald E. Knuth. Reading both helps to reestablish context and a non-dogmatic understanding of the subject. In this paper, Dijkstra's opinion on this case is reported and is even more strong: Donald E. Knuth: I believe that by presenting such a view I am not in fact disagreeing sharply with Dijkstra's ideas, since he recently wrote the following: "Please don't fall into the trap of believing that I am terribly dogmatical about [the go to statement]. I have the uncomfortable feeling that others are making a religion out of it, as if the conceptual problems of programming could be solved by a single trick, by a simple form of coding discipline!"

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• Unix file naming convention for effective tab completion?

  - by thebossman

  I feel like I often name files in such a way that my computer constantly beeps while I program because the tab completion is ambiguous. Before doing a lot of Unix programming, I tended to name related files with the same prefix to indicate their relation. Now I must re-think my approach to folder and file structures and names to program more effectively. What heuristics or rules do you apply when programming to simplify tab completion? Do you use any tools to make tab completion smoother (e.g., emacs icicles)?

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• Interviewing - convincing young interviewers that my experience matters [closed]

  - by ritu

  As requested, I split this question from a two part question I asked at http://stackoverflow.com/questions/2482071/modern-web-development-general-question My question is how do i convince the young programmers who interview me that my years of system programming experience, MFC, Win32 programming are still relevant and I should not be automatically rejected because I don't know the differences between Drupal and <pick your technology>. It seems like I can ask a dozen question that these guys won't be able to answer but somehow because I don't know the latest fad counts against me. I do read, but if you don't use what you read in your daily work, you will never have expert knowledge of it. So bottom line: is the only way for me to take a .NET or Java job is for me to start at the bottom all over?

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• What to learn in my summer holidays?

  - by rgksugan

  I am finishing my graduate and i am into a sotware company. I am a fresher and have some knowledge in Java and JEE. I can program servlets and JSP and have also developed some Swing applications. I dont have that much knowledge in web frameworks. I want to use my holidays usefully at the same time i dont want to spend a lot of time into programming. What can i learn. Suggest me something usefull. I prefer learning some programming tips/algorithms.

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• Keyboard layout for international programmers?

  - by splattne

  I think everybody who had to program using a standard German (or any other international) keyboard layout on Windows (or Mac) will complain about the conundrum of either having all special characters ( [ ] | { } / etc. ) needed for most programming languages "at the fingertip" and "losing" the language specific characters (umlauts ä ö ü etc.) on the keyboard or viceversa: having simple access to umlauts, but not to brackets etc. If you are programming in C / C++ / C# / Java / Javascript for example, it is very exhausting if you have to press Alt-Gr + 7 for every opening curly bracket. It is an ergonomic nightmare and reduces your typing efficiency. What is the best way to cope with this problem? Is there a satisfying solution? Maybe there are special layouts or keyboards which address this issue?

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