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• What's the deal with rubygems on Debian? It's different and strange.

  - by JSW

  I've noticed at least the following oddities around rubygems on Debian (5.0 lenny in my case): Packages go into a different installation location: /var/lib/gems vs /usr/lib/ruby/gems The debian package is rubygems 1.3.6, and updating rubygems to the latest version (1.3.7) doesn't work: $ sudo gem update --system ERROR: While executing gem ... (RuntimeError) gem update --system is disabled on Debian. RubyGems can be updated using the official Debian repositories by aptitude or apt-get. Not all gems appear to work like they do on other systems. For instance, when installing Phusion Passenger, it did not detect the "rack" gem even though it was definitely installed. Manually installing rubygems using the source tarball and reinstalling all my gems (to /usr/lib/ruby/gems) made my problems go away. What's the deal? Why is debian's package different?

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• Modifying an image with OpenGL ?

  - by chmike

  I have a device to acquire XRay images. Due to some technical constrains, the detector is made of heterogeneous pixel size and multiple tilted and partially overlapping tiles. The image is thus distorted. The detector geometry is known precisely. I need a function converting these distorted images into a flat image with homogeneous pixel size. I have already done this by CPU, but I would like to give a try with OpenGL to use the GPU in a portable way. I have no experience with OpenGL programming, and most of the information I could find on the web was useless for this use. How should I proceed ? How do I do this ? Image size are 560x860 pixels and we have batches of 720 images to process. I'm on Ubuntu.

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• Claims-based Authentication: Are strings the essence of claims?

  - by Rising Star

  I've been programming with claims-based authentication for some time now with Windows Identity Foundation. It appears to me that in Windows Identity Foundation, once a user is logged in, the claims are basically strings of information that describe the user. With the old role-based authentication, I could say that a user is or is not a member of a given group, but with claims-based authentication, I can now have strings of information that describe a user. "This user is female". This user was born on "July 6, 1975". "This user logged in using a USB key". Is it the essence of claims-based authentication,that I have strings of information about the user given to the application by the framework?

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• Transfer of directory structure over network

  - by singh

  I am designing a remote CD/DVD burner to address hardware constraints on my machine. My design works like this: (analogous to a network printer) Unix-based machine (acts as server) hosts a burner. Windows-based machine acts as client. Client prepares data to burn and transfers it to the server. Server burns the data on CD/DVD. My question is: what is the best protocol to transfer data over the network (Keeping the same directory hierarchy) between different operating systems?

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• Trust metrics and related algorithms

  - by Nick Gerakines

  I'm trying to learn more about trust metrics (including related algorithms) and how user voting, ranking and rating systems can be wired to stiffle abuse. I've read abstract articles and papers describing trust metrics but haven't seen any actual implementations. My goal is to create a system that allows users to vote on other users and the content of other users and with those votes and related meta-data, determine if those votes can be applied to a users level or popularity. Have you used or seen some sort of trust system within a social graph? How did it work and what were its areas of strength and weaknesses?

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• How to open the command prompt and insert commands using Java?

  - by 404 Not Found

  There have been a few other questions on here sort of like this, but none seem to have any answers. Is it possible to open the command prompt (and I guess any other terminal for other systems), and execute commands in the newly opened window? Currently what I have is this: Runtime rt = Runtime.getRuntime(); rt.exec(new String[]{"cmd.exe","/c","start"}); I've tried adding the next command after the "start", I've tried running another rt.exec containing my command, but I can't find a way to make it work. If it matters, I'm trying to run a command similar to this: java -flag -flag -cp terminal-based-program.jar

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• How do I convert a single char in string to an int

  - by Guest

  Keep in mind, if you choose to answer the question, I am a beginner in the field of programming and may need a bit more explanation than others as to how the solutions work. Thank you for your help. My problem is that I am trying to do computations with parts of a string (consisting only of numbers), but I do not know how to convert an individual char to an int. The string is named "message". for (int place = 0; place < message.size(); place++) { if (secondPlace == 0) { cout << (message[place]) * 100 << endl; } } Thank you.

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• Does program need additional symbols from .so shared library except those declared in header file?

  - by solotim

  In C programming, I thought that a object file can be successfully linked with a .so file as long as the .so file offers all symbols which have been declared in the header file. Suppose I have foo.c, bar.h and two libraries libbar.so.1 and libbar.so.2. The implementation of libbar.so.1 and libbar.so.2 is totally different, but I think it's OK as long as they both offers functions declared in bar.h. I linked foo.o with libbar.so.1 and produced an executable: foo.bin. This executable worked when libbar.so.1 is in LD_LIBRARY_PATH.(of course a symbolic link is made as libbar.so) However, when I change the symbolic link to libbar.so.2, foo.bin could not run and complainted this: undefined symbol: _ZSt4cerr I found this symbol type is 'B' and it does not appear in libbar.so.2. Obviously this symbol has nothing to do with those functions I decared in bar.h. What's wrong here?

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• Existing SQL database android help

  - by basketball4567

  Hey guys, I am new to android programming and i am trying to make an app that will interface with a website i have. It is a movie website with all of its information stored in SQL database. I know how to write the requests and queries in .asp but dont know how to get information from the database in my app. I want the user to be able to enter a movie title, and through a couple of stored procedures that are in my SQL database, return the info on that movie(actor, budget, genre....). I would like to have little info stored on the device, have all of the queries being sent to my SQL server and just have the info being returned. So my question boils down to, how do i link my existing SQL database with an android app. Any help would be great. Thanks Basketball4567

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• Create a javascript chome extention that does not execute in 6 months

  - by user1907657

  I have just started learning programming and I would like to make a script into a chrome extension. Its a basic script and I hope to practice more and more and develop bigger projects and set myself bigger tasks This script has to do the following : reload a page every 20 seconds (say google.com) after 6 months the script must not run (maybe prompt a window saying "its over 6 months") The code should be able to go into a small chrome extension and also the 6 month time period should be absolute not relative to the time the script was started; for example should the browser crash and i have to turn on the extension again it should not restart the 6 month counter. Also if anyone could recommend any good sources for JavaScript to learn (preferably books; nothingIi read online ever seems to stick)

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• General question: Filesystem or database?

  - by poeschlorn

  Hey guys, i want to create a small document management system. there are several users who store their files. each file which is uploaded contains an info which user uploaded it and the document content itself. In a view there are displayed all files of ONE specific user, ordered by date. What would be better: 1) giving the documents a name or metadata(XML) which contain the date and user (and iterate through them to get the metadata) or 2) giving the files a random/unique name and store metadata in a DB? something like this: date | user | filename What would you say and why? The used programming language is java and the DB is MySQL.

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• Best approach to creating a database driven Java website?

  - by Craig Whitley

  I'm fairly new to programming and new to java, but I'd like to jump in the deep end with a little database driven website project. I've read quite a lot about requirements in the 'real world' requesting experience with Spring and Hibernate, so I have those installed on netbeans and a project created (if I hit run I get the default spring page). Now I just need a little guidance as to where to start designing my app (please tell me if I'm getting in a bit too over my head for a beginner!). Should I start off with my classes? - create all my classes as they map to my database tables and decide which attributes and methods each will require? Can anyone suggest any good books for maybe.. making a java based website from scratch (i.e. from design right through to deployment) that might be useful for a beginner? Any help appreciated thanks.

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• Using typedefs (or #defines) on built in types - any sensible reason?

  - by jb

  Well I'm doing some Java - C integration, and throught C library werid type mappings are used (theres more of them;)): #define CHAR char /* 8 bit signed int */ #define SHORT short /* 16 bit signed int */ #define INT int /* "natural" length signed int */ #define LONG long /* 32 bit signed int */ typedef unsigned char BYTE; /* 8 bit unsigned int */ typedef unsigned char UCHAR; /* 8 bit unsigned int */ typedef unsigned short USHORT; /* 16 bit unsigned int */ typedef unsigned int UINT; /* "natural" length unsigned int*/ Is there any legitimate reason not to use them? It's not like char is going to be redefined anytime soon. I can think of: Writing platform/compiler portable code (size of type is underspecified in C/C++) Saving space and time on embedded systems - if you loop over array shorter than 255 on 8bit microprocessor writing: for(uint8_t ii = 0; ii < len; ii++) will give meaureable speedup.

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• How to create an iPad directory view like animation?

  - by mahes25

  In the recent iOS 4.2 update, Apple introduced a nice animation for creating one level directories. I am trying to figure out how to implement a similar animation in my project. I would deeply appreciate it if anyone could give me any pointers to do this efficiently. From my investigation, I believe this animation or effect could be done very efficiently using Core Image which would allow me to write a custom filter. Unfortunately, Core Image is not available in iPhone. So how can do it? I read a blog post that explained a core animation scheme to create an iPad flip clock. The problem I have is similar but has important differences. Besides, I not excited about saving the subimage combinations, which I believe can cause a memory issue. Please enlighten me on the possible ways of doing this animation. I am relatively new to iOS programming, so I might have missed obvious ways of doing this animation or effect.

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• VBA long overflow

  - by HK_CH

  Hi I am trying to do some maths with my VBA excel (prime factorization) and I am hitting the limit of the long data type (runtime error 6 Overflow). Is there any way to get around this and still stay within VBA? (I am aware that the obvious one would be to use another more appropriate programming language) Thanks for help in advance! Thank you, it works in so far that I am able to get the big numbers into the variables now. However when I try to apply the MOD function (bignumber MOD 2 for example) it still fails with error message runtime error 6 Overflow.

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• What books help one to learn to read code?

  - by Daniel

  Lion's Commentary on Unix Sixth Edition with Source Code is a wonderful book to learn how to read code. Reading code is important -- how does one learn how to write excellent code without having read excellent code? But, sadly, while great writers, of fiction and non-fiction, all spend a great deal of time reading stuff, we, programmers, seem to avoid it like the plague. Worse still, programming books usually go the same way. They might show a pattern or a style, but they often avoid showing good, complex code, and helping one go through it. There are exceptions, of course. I hope. So, with that in mind, what books are to be found which help one learn how to read code?

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• Manipulating both unicode and ASCII character set in C#

  - by Murlex

  I have this mapping in my C# application string [,] unicode2Ascii = { { "&#3001;", "\x86" } }; ஹ - is the unicode value for a tamil literal "ஹ". This is the raw hex literal for the unicode value saved by MS Word as a byte sequence. I am trying to map these unicode value "strings" to a hex value under 255 (so as to accommodate non-unicode supported systems). I trying to use string.replace like this: S = S.replace(unicode2Ascii[0,0], unicode2Ascii[0,1]); However the resultant ouput has a ? instead of the actual hex 0x86 stored. Any pointer on how I could set the encoding for the second element of that array to something like windows-1252? Or is there a better way to do this conversion? thanks in advance

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• High quality software examples

  - by Francisco Garcia

  One of the best ways to learn about programming is reading high quality code/projects from great engineers. Which open-source projects do you think is worth looking at? I mean, that code that you can print and sit under a tree with a glass of wine and enjoy reading. If you can, also specify if the software is great to look at because its documentation, design, UML diagrams or just plain code. I believe UML is not very common within open-source projects. Is there such a thing as a project branch that polishes code and design with the sole objective to give other programmers a great example of great software?

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• Is It Worth Using Bitwise Operators In Methods?

  - by user1626141

  I am very new to Java (and programming in general, my previous experience is with ActionScript 2.0 and some simple JavaScript), and I am working my way slowly and methodically through Java: A Beginner's Guide by Herbert Schildt. It is an incredible book. For one thing, I finally understand more-or-less what bitwise operators (which I first encountered in ActionScript 2.0) do, and that they are more efficient than other methods for certain sums. My question is, is it more efficient to use a method that uses, say, a shift right, to perform all your divisions/2 (or divisions/even) for you in a large program with many calculations (in this case, a sprawling RPG), or is it more efficient to simply use standard mathematical operations because the compiler will optimise it all for you? Or, am I asking the wrong question entirely?

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• Advise on starting a new job

  - by Sisiutl

  I hope this isn't too off-topic, but in a week I will start a new job at a manufacturing company managing the development of a new eCommerce site. The company scores about a 3 on the "Joel" test. I will inherit 3 programmers who developed the company web site and do general IT programming. I have the grey hair and credentials to have their initial respect but I'm an engineer, not a manager. I'm looking for practical advise - particularly for the first 90 days - on how to establish myself, keep the team together, and move forward.

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• Questions about "casting operation" in OOP

  - by rhapsodyn

  When programming, we usually use some type-casting operations. When the casting happens on the objects "on the same level", it feels ok. But when it happens on the ojects "on the different levels"(mainly between father and son), it feels weird. Considering this: Class Son extends Father WhenSon s = (Son)father;, it's absolutely unreasonable. Because a "Son" is not a "Father" anymore, "Son" may grow up with some new properties "Father" doesn't have, the casting operation makes these properties unknown. On the other hand, Father f = (Father)son seems reasonable, but according to LSP "An instance of a derived should be able to replace any instance of its superclass" A "Son" can do anything his "Father" can, so the casting operation seems useless. So can i say that these casting operations are agaisnt OO design principle but necessary?

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• Some Simple Questions for knowledge?

  - by dhaliwaljee

  Before Some days my friend ask me some simple questions, but I have no answer. Please tell me about these questions. How many computer programming languages are used all in the world ? I want to create a language like 'java or c#'. What is the procedure for creating a language and how it will create? Which language is used for manipulate Window operating system? What is the procedure of create Operating System like Windows/Linux/Mac and in which language it should create? What is the procedure of create open source framework project in javascript and php?

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• Converting digits, generated by weblog service, to Arabic form

  - by Sorush Rabiee

  sorry if this is irrelevance :-) I need to write something in my html code to convert digits of form 0123456789 to ?????????? (Persian digits uni06F0..uni06F9). the number of visitors is generated by blog service. and I want to convert its digits to Arabic. Counter: ????? ????????????? : <BlogSky:Weblog Counter /> ??? the Persian part of above code mean 'Number of visitors' and 'Persons' (from left to right). but digits are represented in latin (0123...). Is it possible to write something like a function in html? i want it to be a global one for using in weblogs. Note: I don't know anything about web programming languages. I'm not sure about language of above code. (html?)

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• System.Net.Mail.SmtpClient cannot authenticate against a POP3 server, right?

  - by Herchu

  One of our customer seems to have a very old email system, those that ask you to authenticate to the POP3 server before allowing you to send messages through the SMTP server. Regrettably, we have to believe in what our customer tell us for we cannot access their facilities. But as far as I remember, years ago there were mail systems that once you log into the POP3, the STMP server is kept open for a few minutes for the client IP. Our application sends messages by using System.Net.Mail.SmtpClient which seems to be unable to authenticate to those kinds of servers. Is that correct? If so, what would be the simplest workaround? I was thinking of a minimal POP3 implementation (just the login part of the protocol). Would that work? Thanks in advance.

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• Retrieving content of a txt file from URL to Android

  - by eightx2

  I would like to be able to retrieve contents of a .txt file from the internet, and load it in an EditText. I tried using the code on this page: Reading Text File From Server on Android It didn't work, as you might have guessed. I've read on numerous sites about this type of problem, but I can't get anything to work. Someone suggested AndroidHttpClient (http://developer.android.com/reference/android/net/http/AndroidHttpClient.html), but I simply can't find any examples with this. As I'm a newbie in Android programming, I would love if someone could please give me a small example.

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