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• Books for Computer Networking

  - by Altimet Gaandu

  Hi, I am a student of computer engineering from Vasula University, Somalia. We have a subject called Advanced Computer Networks and the following is the list of recommended books: Text Books: 1. B. A. Forouzan, "TCP/IP Protocol Suite", Tata McGraw Hill edition, Third Edition. 2. N. Olifer, V. Olifer, "Computer Networks: Principles, Technologies and Protocols for Network design", Wiley India Edition, First edition. References: 1. W.Richard Stevens, "TCP/IP Volume1, 2, 3", Addison Wesley. 2. D.E.Comer,"TCP/IPVolumeI and II", PearsonEducation. . 3.W.R. Stevens, "Unix Network Programming", Vol. 1, Pearson Education. 4. J.Walrand, P. Var~fya, "High Performance Communication Networks", Morgan Kaufmann. . 5. A.S.Tanenbaum,"Computer Networks", Pearson Education, Fourth Edition. But we have been unable to find these either in the market or on the internet (read: torrents). Please provide download links to any of these books and oblige. Thanks.

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• How do I alias the scala setter method 'myvar_$(myval)' to something more pleasing when in java?

  - by feydr

  I've been converting some code from java to scala lately trying to tech myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

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• Convert a image to a monochrome byte array

  - by Scott Chamberlain

  I am writing a library to interface C# with the EPL2 printer language. One feature I would like to try to implement is printing images, the specification doc says p1 = Width of graphic Width of graphic in bytes. Eight (8) dots = one (1) byte of data. p2 = Length of graphic Length of graphic in dots (or print lines) Data = Raw binary data without graphic file formatting. Data must be in bytes. Multiply the width in bytes (p1) by the number of print lines (p2) for the total amount of graphic data. The printer automatically calculates the exact size of the data block based upon this formula. I plan on my source image being a 1 bit per pixel bmp file, already scaled to size. I just don't know how to get it from that format in to a byte[] for me to send off to the printer. I tried ImageConverter.ConvertTo(Object, Type) it succeeds but the array it outputs is not the correct size and the documentation is very lacking on how the output is formatted. My current test code. Bitmap i = (Bitmap)Bitmap.FromFile("test.bmp"); ImageConverter ic = new ImageConverter(); byte[] b = (byte[])ic.ConvertTo(i, typeof(byte[])); Any help is greatly appreciated even if it is in a totally different direction.

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• The "correct" way of using multilingual support

  - by Felipe Athayde

  I just began working with ASP.NET and I'm trying to bring with me some coding standards I find healthy. Among such standards there is the multilingual support and the use of resources for easily handling future changes. Back when I used to code desktop applications, every text had to be translated, so it was a common practice to have the language files for every languages I would want to offer to the customers. In those files I would map every single text, from button labels to error messages. In ASP.NET, with the help of Visual Studio, I have the resort of using the IDE to generate such Resource Files (from Tools - Generate Local Resource), but then I would have to fill my webpages with labels - at least that is what I've learned from articles and tutorials. However, such approach looks a bit odd and I'm tempted to guess it doesn't smell that good as well. Now to the question: 1) Should I keep every single text in my website as labels and manage its contents in the resource files? It looks/feels odd specially when considering a text with several paragraphs. 2) Whenever I add/remove something, e.g.: a button, to an aspx file I would have to add it to the resource file as well, because generating the resource file again would simply override all my previous changes to it. That doesn't feel like a reusable code at all for me. Any comment suggestion on this one? Perhaps I got it all wrong from tutorials as it doesn't seem like a standardized matter - specially if it required recompiling the entire application whenever some change has to be done.

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• Building a survey to put in a WordPress website using Python/Django

  - by chiurox

  So I've been given a task to build a survey to get data regarding time slot preferences of prospective students for a particular course. I know there are really quick solutions to this like Google Forms, SurveyMonkey, but since it's not unusually hard, I want to implement the survey myself in a totally new language as an opportunity to get started with it and also be able to customize and provide dynamic info to the users who are voting. Although I have done some stuff in PHP, C++, javascript, etc, I'm pretty new to Python+Django framework but it's something I've been meaning to get into since a long time ago. Initially, what I want is to make a grid with the days of the week as columns and time-durations as rows. In each cell I want to provide users a way to choose how strong (high/medium/low) their preference for this particular day+time is. I also want to show how many "votes" have already been cast for this particular preference because this will influence a lot in their decisions and as a result make this process easier when we are going to define the classes. I'll probably store the data in MySQL. Could anyone point me to some really good Python+Django tutorials for my particular purpose? Does anyone think I'm wasting my time with this trivial task by choosing new tools and that I should just use something I already know (like PHP) or a free service or plugin for Wordpress? Thanks!

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• Advanced All In One .NET Framework (should i go for a software factory ?)

  - by alfredo dobrekk

  Hi, i m starting a new project that would basically take input from user and save them to database among about 30 screens, and i would like to find a framework that will allow the maximum number of these features out of the box : .net c#. windows form. unit testing continuous integration logging screens with lists, combo boxes, text boxes, add, delete, save, cancel that are easy to update when you add a property to your classes or a field to your database. auto completion on controls to help user find its way use of an orm like nhibernate easy multithreading and display of wait screens for user easy undo redo tabbed child windows search forms ability to grant access to some functionnalities according to user profiles mvp/mvvm or whatever design patterns either some code generation from database to c# classe or generation of database schema from c# classes some kind of database versioning / upgrade to easily update database when i release patches to application once in production automatic control resizing code metrics analysis some code generator i can use against my entities that would generate some rough form i can rearrange after code documentation generator ... At this point i have 3 options : Build from scratch on top of clr :( Find functionnalities among several open source framework and use them as a stack for infrastucture Find a "software factory" I know its lot but i really would like to use existing code to build upon so i can focus on business rules. What open source tools would u use to achieve these ?

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• PyGTK: Manually render an existing widget at a given Rectangle? (TextView in a custom CellRenderer)

  - by NicDumZ

  Hello! I am trying to draw a TextView into the cell of a TreeView. (Why? I would like to have custom tags on text, so they can be clickable and trigger different actions/popup menus depending on where user clicks). I have been trying to write a customized CellRenderer for this purpose, but so far I failed because I find it extremely difficult to find generic documentation on rendering design in gtk. More than an answer at the specific question (that might be hard/not doable, and I'm not expecting you to do everything for me), I am first looking for documentation on how a widget is rendered, to understand how one is supposed to implement a CellRenderer. Can you share any link that explains, either for gtk or for pygtk, the rendering mechanism? More specifically: size allocation mechanism (should I say protocol?). I understand that a window has a defined size, and then queries its children, saying "my size is w x h, what would be your ideal size, buddy?", and then sometimes shrinks children when all children cant fit together at their ideal sizes. Any specific documentation on that, and on particular on when this happens during rendering? How are rendered "builtin" widgets? What kind of methods do they call on Widget base class? On the parent Window? When? Do they use pango.Layout? can you manually draw a TextView onto a pango.Layout object? This link gives an interesting example showing how you can draw content in a pango.Layout object and use it in a CellRenderer. I guess that I could adapt it if only I understood how TextView widget are rendered. Or perhaps, to put it more simply: given an existing widget instance, how does one render it at a specific gdk.Rectangle? Thanks a lot.

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• Should we retire the term "Context"?

  - by MrGumbe

  I'm not sure if there is a more abused term in the world of programming than "Context." A word that has a very clear meaning in the English language has somehow morphed into a hot mess in software development, where the definition where the connotation can be completely different based on what library you happen to be developing in. Tomcat uses the word context to mean the configuration of a web application. Java applets, on the other hand, use an AppletContext to define attributes of the browser and HTML tag that launched it, but the BeanContext is defined as a container. ASP.NET uses the HttpContext object as a grab bag of state - containing information about the current request / response, session, user, server, and application objects. Context Oriented Programming defines the term as "Any information which is computationally accessible may form part of the context upon which behavioral variations depend," which I translate as "anything in the world." The innards of the Windows OS uses the CONTEXT structure to define properties about the hardware environment. The .NET installation classes, however, use the InstallContext property to represent the command line arguments entered to the installation class. The above doesn't even touch how all of us non-framework developers have used the term. I've seen plenty of developers fall into the subconscious trap of "I can't think of anything else to call this class, so I'll name it 'WidgetContext.'" Do you all agree that before naming our class a "Context," we may want to first consider some more descriptive terms? "Environment", "Configuraton", and "ExecutionState" come readily to mind.

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• How Best to Replace Ugly Queries and Dynamic PL/SQL with C#?

  - by Mike

  Hi, I write a lot of one-off Oracle SQL queries (in Toad), and sometimes they can get complex, involving lots of unions, joins, and subqueries, and sometimes requiring dynamic SQL. That is, sometimes SQL queries require set based processing along with significant procedural processing. This is what PL/SQL is custom made for, but as a language it does not begin to compare to C#. Now and then I convert a PL/SQL procedure to C#, and am always amazed at how much cleaner and easier to both read and write the C# version is. The C# program might for example construct a SQL query string piece by piece and/or run several queries and process them as needed. The C# version is usually much faster as well, which must mean that I'm not very good at PL/SQL either. I do not currently have access to LINQ. My question is, how best to package all these little C# programs, which are really just mini reports, that is, replacements for ugly SQL queries? Right now I'm actually using NUnit to hold them, and calling each report a [Test], even though they aren't really tests. NUnit just happens to provide a convenient packaging framework.

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• First Time Architecturing?

  - by cam

  I was recently given the task of rebuilding an existing RIA. The new RIA that I've designed is based on Silverlight, with a WCF service to connect to MS SQL Server. This is my first time doing something like this, so I'm not sure how to design the entire thing. Basically, the client can look through graphs of "stocks" (allowing the client to choose different time periods, settings, etc). I've written the whole application essentially, but I'm not sure how to put it together. The graphs are supposed to be directly based on the database, and to create the datapoints on the graph, some calculations need to be done (not very expensive ones). The problem I'm having is to decide where to put the calculations (client or serverside? Or half and half?) What factors should I look for to help me decide where the calculations should be done? And how can I go about optimizing this (caching, etc)? Obviously this is a very broad subject, so I'm not expecting an immediate answer, but any help/pointing in the right direction/resources would be appreciated.

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• do the Python libraries have a natural dependence on the global namespace?

  - by msw

  I first ran into this when trying to determine the relative performance of two generators: t = timeit.repeat('g.get()', setup='g = my_generator()') So I dug into the timeit module and found that the setup and statement are evaluated with their own private, initially empty namespaces so naturally the binding of g never becomes accessible to the g.get() statement. The obvious solution is to wrap them into a class, thus adding to the global namespace. I bumped into this again when attempting, in another project, to use the multiprocessing module to divide a task among workers. I even bundled everything nicely into a class but unfortunately the call pool.apply_async(runmc, arg) fails with a PicklingError because buried inside the work object that runmc instantiates is (effectively) an assignment: self.predicate = lambda x, y: x > y so the whole object can't be (understandably) pickled and whereas: def foo(x, y): return x > y pickle.dumps(foo) is fine, the sequence bar = lambda x, y: x > y yields True from callable(bar) and from type(bar), but it Can't pickle <function <lambda> at 0xb759b764>: it's not found as __main__.<lambda>. I've given only code fragments because I can easily fix these cases by merely pulling them out into module or object level defs. The bug here appears to be in my understanding of the semantics of namespace use in general. If the nature of the language requires that I create more def statements I'll happily do so; I fear that I'm missing an essential concept though. Why is there such a strong reliance on the global namespace? Or, what am I failing to understand? Namespaces are one honking great idea -- let's do more of those!

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• Dynamic Select boxes page load

  - by Chris

  Hello, I have a dynamic chained select box that I am attempting to show the value of on a page load. In my chained select box, it will default to the first option within the select box on page load, could anyone provide assitance? I stumbled upon this thread, but I can't seem to translate what they are doing with that answer to my language of CF. Dynamic chained drop downs on page refresh Here is the JS script I am using. function dynamicSelect(id1, id2) { // Feature test to see if there is enough W3C DOM support if (document.getElementById && document.getElementsByTagName) { // Obtain references to both select boxes var sel1 = document.getElementById(id1); var sel2 = document.getElementById(id2); // Clone the dynamic select box var clone = sel2.cloneNode(true); // Obtain references to all cloned options var clonedOptions = clone.getElementsByTagName("option"); // Onload init: call a generic function to display the related options in the dynamic select box refreshDynamicSelectOptions(sel1, sel2, clonedOptions); // Onchange of the main select box: call a generic function to display the related options in the dynamic select box sel1.onchange = function() { refreshDynamicSelectOptions(sel1, sel2, clonedOptions); } } } function refreshDynamicSelectOptions(sel1, sel2, clonedOptions) { // Delete all options of the dynamic select box while (sel2.options.length) { sel2.remove(0); } // Create regular expression objects for "select" and the value of the selected option of the main select box as class names var pattern1 = /( |^)(select)( |$)/; var pattern2 = new RegExp("( |^)(" + sel1.options[sel1.selectedIndex].value + ")( |$)"); // Iterate through all cloned options for (var i = 0; i < clonedOptions.length; i++) { // If the classname of a cloned option either equals "select" or equals the value of the selected option of the main select box if (clonedOptions[i].className.match(pattern1) || clonedOptions[i].className.match(pattern2)) { // Clone the option from the hidden option pool and append it to the dynamic select box sel2.appendChild(clonedOptions[i].cloneNode(true)); } } } Thanks so much for any assistance

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• ASP.Net MVC TDD using Moq

  - by Nicholas Murray

  I am trying to learn TDD/BDD using NUnit and Moq. The design that I have been following passes a DataService class to my controller to provide access to repositories. I would like to Mock the DataService class to allow testing of the controllers. There are lots of examples of mocking a repository passed to the controller but I can't work out how to mock a DataService class in this scenerio. Could someone please explain how to implement this? Here's a sample of the relevant code: [Test] public void Can_View_A_Single_Page_Of_Lists() { var dataService = new Mock<DataService>(); var controller = new ListsController(dataService); ... } namespace Services { public class DataService { private readonly IKeyedRepository<int, FavList> FavListRepository; private readonly IUnitOfWork unitOfWork; public FavListService FavLists { get; private set; } public DataService(IKeyedRepository<int, FavList> FavListRepository, IUnitOfWork unitOfWork) { this.FavListRepository = FavListRepository; this.unitOfWork = unitOfWork; FavLists = new FavListService(FavListRepository); } public void Commit() { unitOfWork.Commit(); } } } namespace MyListsWebsite.Controllers { public class ListsController : Controller { private readonly DataService dataService; public ListsController(DataService dataService) { this.dataService = dataService; } public ActionResult Index() { var myLists = dataService.FavLists.All().ToList(); return View(myLists); } } }

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• T4 trouble compiling transformation

  - by John Leidegren

  I can't figure this one out. Why doesn't T4 locate the IEnumerable type? I'm using Visual Studio 2010. And I just hope someone knows why? <#@ template debug="true" hostspecific="false" language="C#" #> <#@ assembly name="System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" #> <#@ import namespace="System" #> <#@ import namespace="System.Data" #> <#@ import namespace="System.Data.SqlClient" #> <#@ output extension=".cs" #> public static class Tables { <# var q = @" SELECT tbl.name 'table', col.name 'column' FROM sys.tables tbl INNER JOIN sys.columns col ON col.object_id = tbl.object_id "; // var source = Execute(q); #> } <#+ static IEnumerable Execute(string cmdText) { using (var conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=t4build;Integrated Security=True;")) { conn.Open(); var cmd = new SqlCommand(cmdText, conn); using (var reader = cmd.ExecuteReader()) { while (reader.Read()) { } } } } #> Error 2 Compiling transformation: The type or namespace name 'IEnumerable' could not be found (are you missing a using directive or an assembly reference?) c:\Projects\T4BuildApp\T4BuildApp\TextTemplate1.tt 26 9

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• Inversion of control domain objects construction problem

  - by Andrey

  Hello! As I understand IoC-container is helpful in creation of application-level objects like services and factories. But domain-level objects should be created manually. Spring's manual tells us: "Typically one does not configure fine-grained domain objects in the container, because it is usually the responsibility of DAOs and business logic to create/load domain objects." Well. But what if my domain "fine-grained" object depends on some application-level object. For example I have an UserViewer(User user, UserConstants constants) class. There user is domain object which cannot be injected, but UserViewer also needs UserConstants which is high-level object injected by IoC-container. I want to inject UserConstants from the IoC-container, but I also need a transient runtime parameter User here. What is wrong with the design? Thanks in advance! UPDATE It seems I was not precise enough with my question. What I really need is an example how to do this: create instance of class UserViewer(User user, UserService service), where user is passed as the parameter and service is injected from IoC. If I inject UserViewer viewer then how do I pass user to it? If I create UserViewer viewer manually then how do I pass service to it?

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• Has anyone ever had OpenCV work with Python 2.7 on MacOS 10.6?

  - by ?????

  I've been trying on and off for the past 6 months to get OpenCV to work with Python on MacOS. Every time there's a new release, I try again and fail. I've tried both 64-bit and 32-bit, and both the xcode gcc and gcc installed via macports. I just spend the past two days on it, hopeful that the latest OpenCV release, that appears to include Python support directly would work. It doesn't. I've also tried and failed to use this: http://code.google.com/p/pyopencv/ I've been using OpenCV with C++ or Microsoft C++/CLI for the past few years, but I'd love to use it with Python on a Mac because that is my primary development environment. I'd love to hear from anyone who's actually been able to get the opencv python examples to run under Mac OS 10.6, either 32 or 64-bit. My last attempt was to follow the instructions on this page http://recursive-design.com/blog/2010/12/14/face-detection-with-osx-and-python/ with a clean, fresh install of 10.6 on a 64-bit capable Mac. My PYTHONPATH is set, and I can see the cv library in it. But an "import cv" from python fails. Previously, the closest I've ever gotten (again, staring on a clean, fresh 10.6 install) was this: Python 2.7.1 (r271:86882M, Nov 30 2010, 10:35:34) [GCC 4.2.1 (Apple Inc. build 5664)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import cv Fatal Python error: Interpreter not initialized (version mismatch?) Abort trap thrilllap-2:~ swirsky$ I've seen a lot of folks answering similar questions here, but have never seen an definitive answer for it.

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• Zend Framework - Deny access to folders other than public folder

  - by Vincent

  All, I have the following Zend application structure: helloworld - application - configs - controllers - models - layouts - include - library - public - .htaccess - index.php - design - .htaccess The .htaccess in the root folder has the following contents: ##################################################### # CONFIGURE media caching # Header unset ETag FileETag None Header unset Last-Modified Header set Expires "Fri, 21 Dec 2012 00:00:00 GMT" Header set Cache-Control "max-age=7200, must-revalidate" SetOutputFilter DEFLATE # ##################################################### ErrorDocument 404 /custom404.php RedirectMatch permanent ^/$ /public/ The .htaccess in the public folder has the following: Options -MultiViews ErrorDocument 404 /custom404.php RewriteEngine on # The leading %{DOCUMENT_ROOT} is necessary when used in VirtualHost context RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -s [OR] RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -l [OR] RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -d RewriteRule ^.*$ - [NC,L] RewriteRule ^.*$ index.php [NC,L] My vhost configuration is as under: <VirtualHost *:80> ServerAdmin [email protected] DocumentRoot "C:\\xampp\\htdocs\\xampp\\helloworld\\" ServerName helloworld ServerAlias helloworld <Directory "C:\\xampp\\htdocs\\xampp\\helloworld\\"> Options Indexes FollowSymLinks AllowOverride all Order Deny,Allow Deny from all Allow from 127.0.0.1 </Directory> </VirtualHost> Currently, if the user visits, http://localhost, my .htaccess files above make sure, the request is routed to http://localhost/public automatically. If the user visits any other folder apart from public folder from the address bar, he gets a directory listing of that folder. How can I make sure to deny the user access to every other folder except the public folder? I want the user to be redirected to the public folder if he visits any other folder. However, if the underlying code requests something from other folders, (ex: ) it should still work.. Thanks

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• Should frontend and backend be handled by different controllers?

  - by DR

  In my previous learning projects I always used a single controller, but now I wonder if that is good practice or even always possible. In all RESTful Rails tutorials the controllers have a show, an edit and an index view. If an authorized user is logged on, the edit view becomes available and the index view shows additional data manipulation controls, like a delete button or a link to the edit view. Now I have a Rails application which falls exactly into this pattern, but the index view is not reusable: The normal user sees a flashy index page with lots of pictures, complex layout, no Javascript requirement, ... The Admin user index has a completly different minimalistic design, jQuery table and lots of additional data, ... Now I'm not sure how to handle this case. I can think of the following: Single controller, single view: The view is split into two large blocks/partials using an if statement. Single controller, two views: index and index_admin. Two different controllers: BookController and BookAdminController None of these solutions seems perfect, but for now I'm inclined to use the 3rd option. What's the preferred way to do this?

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• Scroll table upwards or downwards using up and down button

  - by Psinyee

  I want to create a banner scrolling function for my homepage. I am not too sure of which programming language to use here. I want to code something similar to: http://www.squidfaceandthemeddler.com/. But I want the footer to remain at the same position while the user scroll the table. Is it possible to get that result? I have create a simple tables and 2 images for the user to click on here is my code for the tables: <div id="banner" style="height:750px; width:600px; overflow:scroll;" > <table width="750px" height="600px"> <tr> <td><a href="sale_1.php"><img src="banner1.png"/></a></td> </tr> </table> <table width="750px" height="600px"> <tr> <td><a href="sale_2.php"><img src="banner2.png"/></a></td> </tr> </table> <table width="750px" height="600px"> <tr> <td><a href="sale_3.php"><img src="banner3.png"/></a></td> </tr> </table> </div> and this is the upwards and downwards button for the scrolling: <table width="750px" height="30px"> <tr> <td align="right"><img src="images/up_arrow.png"/><img src="images/down_arrow.png"/></td> </tr> </table>

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• How do C++ compilers actually pass reference parameters?

  - by T.E.D.

  This question came about as a result of some mixed-langauge programming. I had a Fortran routine I wanted to call from C++ code. Fortran passes all its parameters by reference (unless you tell it otherwise). So I thought I'd be clever (bad start right there) in my C++ code and define the Fortran routine something like this: extern "C" void FORTRAN_ROUTINE (unsigned & flag); This code worked for a while but (of course right when I needed to leave) suddenly started blowing up on a return call. Clear indication of a munged call stack. Another engineer came behind me and fixed the problem, declaring that the routine had to be deinfed in C++ as extern "C" void FORTRAN_ROUTINE (unsigned * flag); I'd accept that except for two things. One is that it seems rather counter-intuitive for the compiler to not pass reference parameters by reference, and I can find no documentation anywhere that says that. The other is that he changed a whole raft of other code in there at the same time, so it theoretically could have been another change that fixed whatever the issue was. So the question is, how does C++ actually pass reference parameters? Is it perhaps free to do copy-in, copy-out for small values or something? In other words, are reference parameters utterly useless in mixed-language programming? I'd like to know so I don't make this same code-killing mistake ever again.

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• JavaScript: How is "function x() {}" different from "x = function() {}" ?

  - by jleedev

  In the answers to this question, we read that function f() {} defines the name locally, while [var] f = function() {} defines it globally. That makes perfect sense to me, but there's some strange behavior that's different between the two declarations. I made an HTML page with the script onload = function() { alert("hello"); } and it worked as expected. When I changed it to function onload() { alert("hello"); } nothing happened. (Firefox still fired the event, but WebKit, Opera, and Internet Explorer didn't, although frankly I've no idea which is correct.) In both cases (in all browsers), I could verify that both window.onload and onload were set to the function. In both cases, the global object this is set to the window, and I no matter how I write the declaration, the window object is receiving the property just fine. What's going on here? Why does one declaration work differently from the other? Is this a quirk of the JavaScript language, the DOM, or the interaction between the two?

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• How to transform a production to LL(1) grammar for a list separated by a semicolon?

  - by Subb

  Hi, I'm reading this introductory book on parsing (which is pretty good btw) and one of the exercice is to "build a parser for your favorite language." Since I don't want to die today, I thought I could do a parser for something relatively simple, ie a simplified CSS. Note: This book teach you how to right a LL(1) parser using the recursive-descent algorithm. So, as a sub-exercice, I am building the grammar from what I know of CSS. But I'm stuck on a production that I can't transform in LL(1) : //EBNF block = "{", declaration, {";", declaration}, [";"], "}" //BNF <block> =:: "{" <declaration> "}" <declaration> =:: <single-declaration> <opt-end> | <single-declaration> ";" <declaration> <opt-end> =:: "" | ";" This describe a CSS block. Valid block can have the form : { property : value } { property : value; } { property : value; property : value } { property : value; property : value; } ... The problem is with the optional ";" at the end, because it overlap with the starting character of {";", declaration}, so when my parser meet a semicolon in this context, it doesn't know what to do. The book talk about this problem, but in its example, the semicolon is obligatory, so the rule can be modified like this : block = "{", declaration, ";", {declaration, ";"}, "}" So, Is it possible to achieve what I'm trying to do using a LL(1) parser?

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• java array pass by reference does not work?

  - by stdnoit

  guys i thought almost all language including java pass array into function as reference (modifiable) but somehow it does not work here. and the testArray is still 1,2,3 with size of 3 strange enough, when if i change result[i] = 2 to a[1] =2; it work . it did pass by reference what is wrong with this code? at the end, i had a = result; (which update the a). did result get removed from stack. that is why a still get to the original a ? i am confused. thanks class Test { public static void main(String[] args) { int[] testArray = {1,2,3}; equalize(testArray, 6); System.out.println("test Array size :" + testArray.length); for(int i = 0; i < testArray.length; i++) System.out.println(testArray[i]); } public static void equalize(int[] a, int biggerSize) { if(a.length > biggerSize) throw new Error("Array size bigger than biggerSize"); int[] result = new int[biggerSize]; // System.arraycopy(a, 0, result, 0, a.length); // int array default value should be 0 for(int i = 0; i < biggerSize; i++) result[i] = 2; a = result; } }

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• Designing model/database for distance between any two locations (that may change)

  - by Yo Ludke

  We should create a web app which has a number of events each with a location (created as user-generated content, so the number of events will be increasingly large). The distance between any events should be available, for example to determine the top 5 closest events and such things. Users may change the locations of events. How should one design the database/model for this (in a scalable way)? I was thinking of doing it with a "distance table" (like so http://www.deutschland-tourist.info/images/entfernungstabelle.gif). Then every time, if a location changes, one row and one column have to be recalculated (this should be done with a delayed job, because it is not important to have the changes instantly). Possible problems in Scaling: Database to large (n² items for n events), too much calculation to be done. For example we should see if this is okay for 10.000 users. If each has created just one event, then this would be 100 million integers... Do you think this would be a good way to do it efficiently? How could one realize such a distance table with an rails model? Is it possible with a SQL databse? Would you start other approaches?

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• Do vs. Run vs. Execute vs. Perform verbs

  - by coffeeaddict

  Before anyone starts to go nuts and red flag this post saying this is "Subjective" which drives me absolutely nuts because everyone has their own intent why they are posting something others feel are subjective. Subjective is subjective to each person, how about that! So with that let me tell you a couple things so that this post does not get flagged by flag happy moderators: 1) There are community guidlines on specific keywords recommended by certain organizations or people (e.g. Microsoft, Lance Hunt, etc.) 2) I want to know what others are using the most and why. Why they feel this verb reads better than others 3) Books even talk about this verb issue (Uncle Bob, etc.), so it's not subjective Now to my actual question: a) What list of verbs are you using for method names? What's your personal or team standard? b) I debate whether to use Do vs. Run vs. Execute vs. Perform and am wondering if any of these are no longer recommended or some that people just don't really use and I should just scratch them. Basically any one of those verbs mean the same thing...to invoke some process (method call). This is outside of CRUDs. For example: ExecutePayPalWorkflow(); that could be also any one of these names instead: DoPayPalWorkflow(); RunPayPalWorkflow(); PerformPayPalWorkflow(); or does it not really matter...because any of those verbs pretty much are understandable as to "what" shows your intent by the other words that follow it "PayPalWorkflow" This discussion can go for any language. I just put the two main tags C# and Java here which is good enough for me to get some solid answers or experiences.

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