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• Creating a computer with pencil and paper [closed]

  - by Justian Meyer

  This concept has been brought to my attention before, but many people might know it from this popular comic here, where he uses stones instead of points on a paper. This concept is so abstract to me. A full-functioning computer that can manage algorithms, input, output, etc. without electricity? Surely, it's difficult to visualize because my definition of a computer is not exactly what the word sounds like COMPUTE-ER. Can someone help me bring the concept to light - the understanding, how to make one, etc? It seems like it'd be an interesting read, although I think I wouldn't be able to make it do anything. Many thanks in advance for responses. I've tried searching Google, but all I got were ways to diagram code and chart ideas. -.Justian.

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• Why people do not like OOP? [closed]

  - by Gabriel Šcerbák

  I do not understand why people choose C++ over Smalltalk in past and why Java over Python or Ruby. What is it that ties people so much to the procedural programming and makes it so difficult to go "all the way" to object oriented programming? What makes OOP hard? Should not objects be an abstraction which is easier to grasp for people, i.e. a more natural one than procedures? Is education the problem (because people tend to learn procedural programming before object oriented)?

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• Get local network interface addresses using only proc?

  - by Matt Joiner

  How can I obtain the (IPv4) addresses for all network interfaces using only proc? After some extensive investigation I've discovered the following: ifconfig makes use of SIOCGIFADDR, which requires open sockets and advance knowledge of all the interface names. It also isn't documented in any manual pages on Linux. proc contains /proc/net/dev, but this is a list of interface statistics. proc contains /proc/net/if_inet6, which is exactly what I need but for IPv6. Generally interfaces are easy to find in proc, but actual addresses are very rarely used except where explicitly part of some connection. There's a system call called getifaddrs, which is very much a "magical" function you'd expect to see in Windows. It's also implemented on BSD. However it's not very text-oriented, which makes it difficult to use from non-C languages.

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• How to organize XIB files with many overlapping elements?

  - by alltom

  I have some XIB files which are very difficult to edit because many of the subviews overlap each other completely. For example, if I position a popup volume slider where it will pop up, it covers some UILabels which become impossible to click. My only chance to be able to edit them is to double-click on them in the Document window tree, move them aside, edit, then move them back. Sometimes there are 3 or more widgets that occupy the same location in the XIB, even though only a few are visible at a time while the application is running. How are conditionally-visible screen elements actually supposed to be organized? I would like to be able to hide groups of views to reveal what's beneath them, but I don't see a way to do that in IB. If I create UIViewControllers for every group, I can edit them in separate windows, but I can't see them in context, and I need a lot of view controllers...

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• oracle display for every stored procedure the execution time

  - by CC

  Hi all. I'm working on a stored procedure. Inside this one, there are many call to the other stored procedures. There are a bunch of them. I was wondering if there is a option to be able to have the execution time of every stored procedure involved, every function (with a start and end time, ior something like that). The idea is that I need to optimise it and I should touch every part, and since I not sure where is the longest execution time, is a bit difficult. And after a modification I would like the see the hole process if it's shorter or not. If I call the procedure from unix, using sql plus, I have no log. If I call it from TOAD, it's blocked until the end. Any idea? I'm not a dba, so I don't have many rights on the database, I'm just a regular user. Thanks for any advice. C.C.

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• How to detect circles accurately

  - by user1767798

  Is there any way to accurately detect circles in opencv? I was using hough transform which give me good result but most of the time, shadow of the object and surrounding,light etc gives bad results, so am looking for options other than hough circles, accurate detection is very important for my project. My basic approach so far is to find some spheres in the image taken in realtime. I am using houghcircle to find the spheres and base later calculations on the radius I am getting from that. If the background is plain and nothing the sphere detect without problem, however if I am taking that image in my room where the background will have other objects it's often difficult to detect. So am looking for some other approach.

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• Serial numbers generation without user data

  - by Sphynx

  This is a followup to this question. The accepted answer is generally sufficient, but requires user to supply personal information (e.g. name) for generating the key. I'm wondering if it's possible to generate different keys based on a common seed, in a way that program would be able to validate if those keys belong to particular product, but without making this process obvious to the end user. I mean it could be a hash of product ID plus some random sequence of characters, but that would allow user to guess potential new keys. There should be some sort of algorithm difficult to guess.

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• How are CD Keys generated?

  - by The Rook

  CD Keys are the defacto-standard as an anti-piracy measure. To be honest this strikes me as Security Though Obscurity, although I really have no idea how CD Keys are generated. What is a good (secure) example of CD Key generation? What cryptographic primitive (if any) are they using? Is it a message digest? If so what data would they be hashing? What methods do developers employ to make it difficult for crackers to build their own key generators?

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• Dynamically create labels in gas macros?

  - by pgod

  Hi everyone, I would like to dynamically create a set of labels in an assembly function using a gas macro. I would like to do something like this: .macro set_up_jumptab_entry prefix, from=0, to=10 .quad \prefix_\item .if \to-\from set_up_jumptab_entry \prefix,"(\from+1)",\to .endif .endm set_up_jumptab_entry myfunc 0 10 Here \prefix_\item would be something like myfunction_7. Now, I can find lots of examples of recursive invocation, but I haven't found one of just label concatenation involving passed-in macro arguments. Gas is quite poorly documented, so answering this question is difficult for me. Can you concatenate arguments to macros with other tokens to make single tokens? What's your favorite gas assembler reference?

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• How to vertically align an inline image with inline text following it?

  - by amn

  Is there any way to vertically align an image element generated by a "content" property as part of a ":before" selector, next to adjacent inline text? In other words, I have <a href="..." class="facebook">Share on Facebook</a> As I don't want to pollute my markup with unnecessary IMG elements that only have to do with style, I resort to adding a small icon to the left of the link, via CSS (except that it does not align properly, hence the question): a.facebook:before { content: url(/style/facebook-logo.png); } I tried adding a "vertical-align: middle" (one of the most notoriously difficult aligning concepts to grasp in CSS, in my opinion, is that very property) but it has no effect. The logo aligns with text baseline, and I don't want to hardcode pixel offsets, because frankly text size differs from browser to browser, etc. Is there any solution for this? Thanks.

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• How do Arrays work in C#?

  - by Slateboard

  I know that they are used to store data, but I have a difficult time understanding exactly how to use them in a program. In addition, I found this site with a tetris clone tutorial (the actual tutorial is missing). It uses arrays, but I can't really make sense of how it works. Here's an example of the code - public int[, ,] TShape = new int[4, 4, 2] { {{1, 0}, {0, 1}, {1, 1}, {2, 1}}, {{1, 0}, {0, 1}, {1, 1}, {1, 2}}, {{0, 0}, {1, 0}, {2, 0}, {1, 1}}, {{0, 0}, {0, 1}, {1, 1}, {0, 2}}}; Could it be that I'm looking too hard into this, or perhaps there's something I'm not grasping about it?

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• Is it possible to raise an error if a variable assignment in a select returns multiple values?

  - by Brann

  I just found a bug on one of my softwares where I had forgotten a where clause. The code was something like that : declare @foo bigint declare @bar bigint select @foo = foo, @bar=bar from tbFooBar where (....a long list of condition goes there) (... and an extra condition should have went there but I forgot it) Unfortunately, the where clause I forgot was useful in very specific corner cases and the code went through testing successfully. Eventually, the query returned two values instead of one, and the resulting bug was a nightmare to track down (as it was very difficult to reproduce, and it wasn't obvious at all that this specific stored procedure was causing the issue we spotted) Debugging would have been a lot easier if the @foo=foo had raised an exception instead of silently assigning the first value out of multiple rows. Why is that this way? I can't think of a situation where one would actually want to do that without raising an error (bearing in mind the clauses 'distinct' and 'top' are there for a reason) And is there a way to make sql server 2008 raise an error if this situation occurs ?

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• How to get around circular references in Visual Studio Web Project?

  - by joebeazelman

  I am trying to create a set of WCF web services for an existing website that uses web site instead of a web application project. I would like to create a DLL that I drop into the Bin folder instead of writing all my code inside the App_Code directory. Ideally, I want to create a project and reference it from the web site, but I am running into a difficult situation. The DLL will need to reference configuration and other DLLs located inside the bin folder of the website causing a circular reference. How do I get around this issue?

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• Css Multiple background-color

  - by Khanh TO

  I'm a novice in Css and it's difficult to search for this specific case on the internet, so I post a question here. I'm working on an existing code base and I see something like this. li { background-color: #000 \9; background-color: rgba(0, 0, 0, 0); } I don't understand the meaning of \9. But it looks to me they are duplicates and I should remove one of them. Could you please explain the \9 and should I remove one of them? Thanks.

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• JRI Fatal Error on Ubuntu

  - by Peter Jackson

  I have successfully installed JRI and rJava on Windows 7. I am now trying to get it to work on Ubuntu with 64bit OS. I can make rJava calls from within R but getting JRI to work is more difficult. I am running NetBeans 7.1.2 and I have followed various tricks in setting R_HOME and java.library.path to enable all the classes to be loaded. That is, I am past the error messages such as "jri library not found" and "R_HOME not set". From my java code,I can see that R_HOME = /usr/lib64/R. The error message I get now is Fatal error: you must specify '--save', '--no-save' or '--vanilla' This happens when Rengine is first called: Rengine r = new Rengine(args,false,null); This appears to be an error message from R; it seems to be expecting a command line argument. I haven't seen any posting with this error message. Any ideas? Thanks, Peter

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• how to integrate Zend Framework MVC with existing site

  - by Joel

  Hi guys, So I'm slowly tackling OO and Zend Framework and their MVC process in particular. I have an existing website and web-based calendar application that was designed by me, but coded by a different person and done procedurally. I understand that it will be very difficult for my application to ever be completely OO without a full re-write, and I'm fine with that. I have a lot of updates and modifications I want to do in the future, so I'm wanting to start replacing some of the basic components (login, authentication. etc) now, and continue to learn as I go. Again, I'm really a newbie at programming and OO. What I'm wondering is if I'm wanting to incorporate the Framework, then would I just first drop my whole site into the /public folder of the Framework and then start pulling functionality out from there?

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• Cast Object to JTable?

  - by Chris

  I am trying to implement a ListSelectionListener for some of my JTables. Simply (at the moment) the ListSelectionListener is supposed to simply return the text of the cell that was selected. My program design has several JTables and I would like to have one ListSelectionListener work for them all. In the valueChanged event of the ListSelectionListener I thought it was possible to do something like: private class SelectionHandler implements ListSelectionListener { public void valueChanged(ListSelectionEvent e) { JTable table = (JTable)e.getSource(); String data = (String) table.getValueAt(table.getSelectedRow(), 0); // Print data } } But when I do this I a ClassCastException error. Is there a way to do something like this? One solution I thought of was to compare the source of the event (e.getSource()) to all my JTables to see if they were equivalent (big if block) and then just calling .getValueAt inside that block but that would making the code in the future difficult if tables were to be added or removed.

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• ASP.NET Long Process and Sending updates to Browser

  - by user204588

  Hello, I've asked this before but I was hoping for another answer and perhaps some code samples because I've been having a difficult time with this. I have an asp.net page. The user hits the "Run" button and I have code IN AN ASSEMBLY, not in the APP_CODE folder that is called and runs a long process that moves product info from a file into the database. While the user waits, I would like them to see status updates like what product the import process in on and status info. I'm assuming I'd break off into another thread and use Ajax but I have no idea how to do this. Some code samples would be very helpful, thanks.

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• VB6 Parser/Lexer/Scripter

  - by rlb.usa

  I've got a game in VB6 and it works great and all, but I have been toying with the idea of creating a scripting engine. Ii'm thinking I'd like VB6 to read in flat text script files for me and then lex/parse/execute them. I have good programming experience, and I've built a simple C compiler, as well as a LOGO emulator before. My question is: Are there any tools that I can use, like Lexx/Yakk/Bison to help me? How should I approach this problem in regards to lexing, parsing, and feeding the commands back to VB6 so I can handle them? Is this idea a BAD IDEA in the sense that there are too many obstacles in the way (For example, building minesweeper in assembly, though not impossible, is very difficult, and a bad idea.)?

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• ASP.NET Controls with Highly Customizable GUI

  - by micha12

  We are developing an ASP.NET web application where some of the features that we will need to implement are quite standard: for example, a chat between users, a forum, etc. There are ASP.NET chats and forums components available. However, they all have a predetermined GUI and html markup that is almost impossible to change and very difficult to customize. And this is a very common situation for most controls like grids, etc.: you have very low control over the html markup that is being generated by the control. In our case, our web app will have its own web design created by a professional web designer in PhotoShop, and then it will but transformed into html markup that will then be transformed in aspx pages. We would ideally like to create the html markup for the forum and chat by ourselves, and use only the non-GUI part of the ASP.NET components. Is this approach feasible? Has anyone dealt with such approach in practice?

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• How to reference an object in a lower fragment in android

  - by Silas Greenback

  I am trying to build a help screen that is going to go on a mediaplayer. The idea is to put a fragment with a transparent theme on top of the current view. (See How do I create a help overlay like you see in a few Android apps and ICS? for the basic idea). Now, I understand the steps in the mentioned link, but how do I connect the circles and arrows and paragraphs next to each one (explaining what each one was) to the lower object? Example, I have an object: R.id.music_button and I want there to be and arrow that points to music button. Trying to support as many devices as we do it will be very difficult to just draw a few pictures as part of the top layout and expect them to line up. Again, how do I reference an object on a fragment below the top level? Thanks

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• Getting plane slices from array data

  - by umanga

  Greetings all, I read 3d grid data (from multiple TIF images) into a structure as follows : typedef struct VolumeData{ int nx; int ny; int nz; unsigned char *data; // size is nx*ny*nz } Now I want to get the plane slices from this 1-D grid data: eg: unsigned char* getXYPlaneStack(VolumeData *vol,int z); I could implement above function because the *data array stores image stack. But i am having difficult time implement along the other axes: unsigned char* getYZPlaneStack(VolumeData *vol,int x); and unsigned char* getXZPlaneStack(VolumeData *vol,int y); any easy algorithm for this? thanks in advance.

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• Closing a window when it's "no longer needed".

  - by Mason Blier

  This is kind of a hard question to describe, and I've searched for about an hour now to no avail. Essentially, picture a small 'flyout' window like the Windows 7 Wireless Control or the Volume Slider from the system tray(notification area). When you click on the icon, the application pops up with focus, and if you click off of it, the window destroys itself. I thought it woudl be easily solved by simply having my window destroy it self when it loses focus (I've been listening for WM_KILLFOCUS), but the problem is, if the icon is clicked, my window does not always get focus. Since this isn't the case, if the user clicks my icon, and then clicks away because it was a mistake (on the desktop say), then how can I set my app to close? I've tried messing with SPY++ but checking the volume control / wireless control apps are proving difficult as they disappear when I try to get their window/process handles. Thanks!

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• Why does SQLAlchemy with psycopg2 use_native_unicode have poor performance?

  - by Bob Dover

  I'm having a difficult time figuring out why a simple SELECT query is taking such a long time with sqlalchemy using raw SQL (I'm getting 14600 rows/sec, but when running the same query through psycopg2 without sqlalchemy, I'm getting 38421 rows/sec). After some poking around, I realized that toggling sqlalchemy's use_native_unicode parameter in the create_engine call actually makes a huge difference. This query takes 0.5secs to retrieve 7300 rows: from sqlalchemy import create_engine engine = create_engine("postgresql+psycopg2://localhost...", use_native_unicode=True) r = engine.execute("SELECT * FROM logtable") fetched_results = r.fetchall() This query takes 0.19secs to retrieve the same 7300 rows: engine = create_engine("postgresql+psycopg2://localhost...", use_native_unicode=False) r = engine.execute("SELECT * FROM logtable") fetched_results = r.fetchall() The only difference between the 2 queries is use_native_unicode. But sqlalchemy's own docs state that it is better to keep use_native_unicode=True (http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html). Does anyone know why use_native_unicode is making such a big performance difference? And what are the ramifications of turning off use_native_unicode?

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• How to use database to generate multiple folder content page?

  - by VenomVipes

  Scenario :I am trying to build a Mobile Entertainment Portal. It will enable users to download Music & Movies to their Cell Phones... Problem Exp : Suppose I upload 100 folders of Songs, each folder is for one Album. I want a way to generate a page with all the folders name (Album Name) in it. If user click on the page, they should be taken to a page where they get list of all songs in the album. Clicking on any song name will let them download it. Can it be done anyway or will I have to manually design each of the 3 pages for each album. If I do that, its time consuming and also will be difficult to change anything like footer, header...

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