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• Application design question, best approach?

  - by Jamie Keeling

  Hello, I am in the process of designing an application that will allow you to find pictures (screen shots) made from certain programs. I will provide the locations of a few of the program in the application itself to get the user started. I was wondering how I should go about adding new locations as the time goes on, my first thought was simply hard coding it into the application but this will mean the user has to reinstall it to make the changes take affect. My second idea was to use an XML file to contain all the locations as well as other data, such as the name of the application. This also means the user can add their own locations if they wish as well as sharing them over the internet. The second option seemed the best approach but then I had to think how would it be managed on the users computer. Ideally I'd like just a single .exe without the reliance on any external files such as the XML but this would bring me back to point one. Would it be best to simply use the ClickOnce deployment to create an entry in the start menu and create a folder containing the .exe and the file names? Thanks for the feedback, I don't want to start implementing the application until the design is nailed.

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• Xlib.h and Xutil.h not found in Eclipse, how can I fix this?

  - by eclipseNoob

  Hi, I'm a newbie to Eclipse IDE for C/C++ development. I just installed MingW and set it up as my system's environment variable. I am trying to make an application that uses the X library but eclipse cant seem to find it. Eclipse works with any other simple standard library functions but it cant find the X library. Please Help! Here's a sample code snippet that's failing: #include <stdio.h> #include <X11/Xlib.h> // Can't find this #include <X11/Xutil.h> // Or this... int main() { printf("Hello"); return 0; } Do I have to download the X library from somewhere? If so then from where and where do I paste it to? Please tell me what to do in order for me to start coding using the Xlib in Eclipse. If you find any useful links, please dont hesitate to post. Thanks.

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• P0ST variables to web server?

  - by OverTheRainbow

  Hello I've been trying several things from Google to POST data to a web server, but none of them work: I'm still stuck at how to convert the variables into the request, considering that the second variable is an SQL query so it has spaces. Does someone know the correct way to use a WebClient to POST data? I'd rather use WebClient because it requires less code than HttpWebRequest/HttpWebResponse. Here's what I tried so far: Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim wc = New WebClient() 'convert data wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded") Dim postData = String.Format("db={0}&query={1}", _ HttpUtility.UrlEncode("books.sqlite"), _ HttpUtility.UrlEncode("SELECT id,title FROM boooks")) 'Dim bytArguments As Byte() = Encoding.ASCII.GetBytes("db=books.sqlite|query=SELECT * FROM books") 'POST query Dim bytRetData As Byte() = wc.UploadData("http://localhost:9999/get", "POST", postData) RichTextBox1.Text = Encoding.ASCII.GetString(bytRetData) Exit Sub Dim client = New WebClient() Dim nv As New Collection nv.Add("db", "books.sqlite") nv.Add("query", "SELECT id,title FROM books") Dim address As New Uri("http://localhost:9999/get") 'Dim bytRetData As Byte() = client.UploadValues(address, "POST", nv) RichTextBox1.Text = Encoding.ASCII.GetString(bytRetData) Exit Sub 'Dim wc As New WebClient() 'convert data wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded") Dim bytArguments As Byte() = Encoding.ASCII.GetBytes("db=books.sqlite|query=SELECT * FROM books") 'POST query 'Dim bytRetData As Byte() = wc.UploadData("http://localhost:9999/get", "POST", bytArguments) RichTextBox1.Text = Encoding.ASCII.GetString(bytRetData) Exit Sub End Sub Thank you.

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• pthreads: reader/writer locks, upgrading read lock to write lock

  - by ScaryAardvark

  I'm using read/write locks on Linux and I've found that trying to upgrade a read locked object to a write lock deadlocks. i.e. // acquire the read lock in thread 1. pthread_rwlock_rdlock( &lock ); // make a decision to upgrade the lock in threads 1. pthread_rwlock_wrlock( &lock ); // this deadlocks as already hold read lock. I've read the man page and it's quite specific. The calling thread may deadlock if at the time the call is made it holds the read-write lock (whether a read or write lock). What is the best way to upgrade a read lock to a write lock in these circumstances.. I don't want to introduce a race on the variable I'm protecting. Presumably I can create another mutex to encompass the releasing of the read lock and the acquiring of the write lock but then I don't really see the use of read/write locks. I might as well simply use a normal mutex. Thx

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• Filter large amounts of data from a HTML table w/ jQuery

  - by Bry4n

  I work for a transit agency and I have large amounts of data (mostly times), and I need a way to filter the data using two textboxes (To and From). I found jQuery quick search, but it seems to only work with one textbox. If anyone has any ideas via jQuery or some other client side library, that would be fantastic. Ideal example: To: [Textbox] From:[Textbox] <table> <tr> <td>69th street</td><td>5:00pm</td><td>5:06pm</td><td>5:10pm</td><td>5:20pm</td> </tr> <tr> <td>Millbourne</td><td>5:09pm</td><td>5:15pm</td><td>5:20pm</td><td>5:25pm</td> </tr> <tr> <td>Spring Garden</td><td>6:00pm</td><td>6:15pm</td><td>6:20pm</td><td>6:25pm</td> </tr> </table> I have an HTML page with a giant table on it listing the station names and each stations times. I want to be able to put my starting location in one box and my ending location in another box and have all the items in the table disappear that don't relate to either of the two locations typed in, leaving only two rows that match what was typed in (even if they don't spell it right or type it all the way) Similar to the jQuery quick search plugin

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• How to return a value from facebook javascript connect api fucntions

  - by dezwald

  I am trying to create wrapper functions on facebook javascript connect api methods. My problem is that i can not return a value within the facebook api FB_RequireFeatures method. i want my isFBConnected() function to return true or false based on if i'm logged into facebook or not. What is happening is that when i return true it returns it to the child function, which makes sense however, my global "login" variable does not get set to true. I've tried setting a timeout to wait until the facebook connect finishes executing and still no luck. any help or other solutions are welcome! my isFBConnected wrapper function is stated below: function isFBConnected(){ var api_key = '<?=$this->apiKey?>'; var channel_path = '<?=$this->xdReceiver?>'; var host_url = '<?=$this->hostUrl?>'; var servicePathShort = '<?=$this->servicePathShort?>'; var login = false; FB_RequireFeatures(["Api"], function(){ // Create an ApiClient object, passing app's API key and // a site relative URL to xd_receiver.htm FB.Facebook.init(api_key, channel_path); var api = FB.Facebook.apiClient; // If FB user session exists - load stats data if(api.get_session()!=null){ if(api.get_session().uid!='' && api.get_session().uid!=undefined){ login = true; alert(api.get_session().uid); return true; } } login = false; return false; }); return false; }

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• Anchor tags are blank

  - by ryanday

  I'm having a problem where the my anchor tags sometimes aren't displaying their links. This is happening on Mobile Safari on multiple iPhones, and in the iPhone simulator. I'm using jQtouch r147, PhoneGap, and jQuery 1.4.2. I'm generating the data from a database call, and adding anchor tags to a list like this: for(var i=0;i<data.rows.length;i++) { var item = $('<li></li>'); var name = data.rows.item(i).name; var anchor = $('<a href="#lpage">'+name+'</a>'); item.addClass('arrow'); // This line always displays the name, even when I can't see // the name in the browser debug.log('The name: ' + name); (function(info) { anchor.bind('tap', function(e) { debug.log('Touch start ' + info.id); }); })(data.rows.item(i)); item.append(anchor); if( anchor.html() == null ) { debug.log('html is blank'); } $('#myUL').append(item); } Sometimes my list of names shows fine(http://imagebin.org/101462), and sometimes it is just blank(http://imagebin.org/101464). When the list is blank, I see the debug.log() line show me 'html is blank', and I also see the log line show me that the variable 'name' does, in fact, contain a valid name. When I check for anchor.html() == null, I've also tried to .remove() the anchor tag, and re-create it. But it always comes back without the name displayed. This happens on the mobile device and in the simulator, but I've never seen it happen in Safari or in Chrome. Has anyone seen something like this? I can't find the cause, and I can't get it to stop. Thank you for any ideas or suggestions!

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• How can I create Wikipedia's footnote highlighting solely with jQuery

  - by andrew.bachman

  I would like to duplicate Wikipedia's footnote highlighting from in-text citation click solely in jQuery and CSS classes. I found a webpage that describes how to do so with CSS3 and then a JavaScript solution for IE. I would like however to do so solely with jQuery as the site I'm doing it on already has a bunch of jQuery elements. I've come up with a list of the process. In-Text Citation Clicked Replace highlight class with standard footnote class on <p> tag of footnotes that are already highlighted. Add highlight to the appropriate footnote Use jQuery to scroll down the page to appropriate footnote. I've come up with some jQuery so far but I'm extremely new to it relying heavy on tutorials and plugins to this point. Here is what I have with some plain English for the parts I haven't figured out yet. $('.inlineCite').click(function() { $('.footnoteHighlight').removeClass('footnoteHighlight').addClass('footnote'); //add highlight to id of highlightScroll //scroll to footnote with matching id }); If I had a method to pass a part of the selector into the function and turn it into a variable I believe I could pull it off. Most likely I'm sure one of you gurus will whip something up that puts anything I think I have done to shame. Any help will be greatly appreciated so thank you in advance. Cheers.

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• C/C++: feedback in analyzing a code example

  - by KaiserJohaan

  Hello, I have a piece of code from an assignment I am uncertain about. I feel confident that I know the answer, but I just want to double-check with the community incase there's something I forgot. The title is basically secure coding and the question is just to explain the results. int main() { unsigned int i = 1; unsigned int c = 1; while (i > 0) { i = i*2; c++; } printf("%d\n", c); return 0; } My reasoning is this: At first glance you could imagine the code would run forever, considering it's initialized to a positive value and ever increasing. This of course is wrong because eventually the value will grow so large it will cause an integer overflow. This in turn is not entirely true either, because eventally it will force the variable 'i' to be signed by making the last bit to 1 and therefore regarded as a negative number, therefore terminating the loop. So it is not writing to unallocated memory and therefore cause integer overflow, but rather violating the data type and therefore causing the loop to terminate. I am quite sure this is the reason, but I just want to double check. Any opinions?

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• When do instance variables get initialized and values assigned?

  - by AKh

  When doees the instance variable get initialized? Is it after the constructor block is done or before it? Consider this example: public abstract class Parent { public Parent(){ System.out.println("Parent Constructor"); init(); } public void init(){ System.out.println("parent Init()"); } } public class Child extends Parent { private Integer attribute1; private Integer attribute2 = null; public Child(){ super(); System.out.println("Child Constructor"); } public void init(){ System.out.println("Child init()"); super.init(); attribute1 = new Integer(100); attribute2 = new Integer(200); } public void print(){ System.out.println("attribute 1 : " +attribute1); System.out.println("attribute 2 : " +attribute2); } } public class Tester { public static void main(String[] args) { Parent c = new Child(); ((Child)c).print(); } } OUTPUT: Parent Constructor Child init() parent Init() Child Constructor attribute 1 : 100 attribute 2 : null When the memory for the atribute 1 & 2 are allocated in the heap ? Curious to know why is attribute 2 is NULL ? Are there any design flaws?

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• How to detect if a file is PDF or TIFF ?

  - by eviljack

  Please bear with me as I've been thrown into the middle of this project without knowing all the background. If you've got WTF questions, trust me, I have them too. Here is the scenario: I've got a bunch of files residing on an IIS server. They have no file extension on them. Just naked files with names like "asda-2342-sd3rs-asd24-ut57" and so on. Nothing intuitive. The problem is I need to serve up files on an ASP.NET (2.0) page and display the tiff files as tiff and the PDF files as PDF. Unfortunately I don't know which is which and I need to be able to display them appropriately in their respective formats. For example, lets say that there are 2 files I need to display, one is tiff and one is PDF. The page should show up with a tiff image, and perhaps a link that would open up the PDF in a new tab/window. The problem: As these files are all extension-less I had to force IIS to just serve everything up as TIFF. But if I do this, the PDF files won't display. I could change IIS to force the MIME type to be PDF for unknown file extensions but I'd have the reverse problem. http://support.microsoft.com/kb/326965 Is this problem easier than I think or is it as nasty as I am expecting?

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• Obfuscating ASP.Net dll breaks web application.

  - by uriDium

  I wouldn't usually bother to obfuscate a web application DLL but right now I have to share some server space with someone who might have a conflict of interest and might be tempted to steal the deal and decompile it. Not an ideal solution I know but hey. So I am using VS 2005, a web deployment project (which compiles into a single DLL) and Dotfuscator community edition. When I obfuscate the DLL the web application breaks and I get some message like Could not load type 'Browse' from assembly MyAssembly So I searched around and found that if I disable renaming then it should fix it. Which it does. But now when I look at the DLL using .Net reflector I can see everything again. So this seems kind of pointless. Is there a way to get this to work? Is there a better way to protect my DLL from someone I have to share a server with? UPDATE: I figured out my problem. All the classnames have changed but now all my <%@ Page Language="C#" AutoEventWireup="true" CodeFile="mycode.aspx.cs" Inherits="mycode" % is incorrect because mycode no longer exists. It is now aef or something. Is there any tool out there that will also change the names of the Codefile and Inherits tags?

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• Setting up a domain using WAMP and NameCheap's DNS service

  - by Mike Jones

  So, I've been working on this for far longer than I should be and I'm quite thoroughly perplexed and lost. I apologize if this turns out to be a facile question, but I'm entirely befuddled and very much in need of some guidance. Earlier today I registered a cheap .info domain on NameCheap just to play around with as I learn webdev. I have WAMP installed on my computer and I've been testing my projects through localhost. I thought it would be a good idea to have a domain at my disposal in order to understand how it works and better test my work. NameCheap has a complimentary DNS service (not that I entirely understand what DNS is, although I tried), so I'm using that. I direct both the "@" and "www" host names to my IP address, as shown in the below tutorial: https://www.namecheap.com/support/knowledgebase/article.aspx/319/78/how-can-i-setup-an-a-address-record-for-my-domain However, now when I go to the URL of the domain I bought, it confronts me with a login box that seems to be coming from my wifi network. How do I set this up so that it hosts the information in my WAMP server? Thanks in advance for any help, I really appreciate it. And, as a side-note, what should read (print or online) to better understand the structure of the internet? I've been studying HTML/CSS/Javascript, but I'm not sure where to look for pragmatic and comprehensive information on how the internet works and how to utilize it as a website administrator. Thanks so much.

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• Fitting title for my position

  - by lithander

  In the last 2 years my company has developed a boxed and full-price computer game. All the software development has been done collaboratively by me and my co-developer. We know each other from university and got hired at the same day to equal conditions and we share the same responsibilites including the decisions of what technology to license and how to spend development resources and even how team-workflow is organized. But I struggle to find the correct wording for my position. Can I call myself a senior developer with only 3 years working-experience? Can I call myself lead programmer if I don't really have a team to "lead"? All these fancy names used in the industry (Technical Lead, Development Lead, Software Architect) seem to imply that you aren't actually coding anymore or have staff under you. On the other hand titles like "Programmer" or "Software Engineer" seem to imply that there's someone between you and the project management. That makes it hard to fill out a resume or even the badges you typically wear on conferences... people tend to judge you by your title and I'd like to avoid confusion where possible.

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• Structuring input of data for localStorage

  - by WmasterJ

  It is nice when there isn't a DB to maintain and users to authenticate. My professor has asked me to convert a recent research project of his that uses Bespin and calculates errors made by users in a code editor as part of his research. The goal is to convert from MySQL to using HTML5 localStorage completely. Doesn't seem so hard to do, even though digging in his code might take some time. Question: I need to store files and state (last placement of cursor and active file). I have already done so by implementing the recommendations in another stackoverflow thread. But would like your input considering how to structure the content to use. My current solution Hashmap like solution with javascript objects: files = {}; // later, saving files[fileName] = data; And then storing in localStorage using some recommendations localStorage.setObject(files): Currently I'm also considering using some type of numeric id. So that names can be changed without any hassle renaming the key in the hashmap. What is your opinion on the way it is solved and would you do it any differently?

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• How Can i Create This Complicated Query ?

  - by mTuran

  Hi, I have 3 tables: projects, skills and project_skills. In projects table i hold project's general data. Second table skills i hold skill id and skill name also i have projects_skills table which is hold project's skill relationships. Here is scheme of tables: CREATE TABLE IF NOT EXISTS `project_skills` ( `project_id` int(11) NOT NULL, `skill_id` int(11) NOT NULL, KEY `project_id` (`project_id`), KEY `skill_id` (`skill_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci; CREATE TABLE IF NOT EXISTS `projects` ( `id` int(11) NOT NULL AUTO_INCREMENT, `employer_id` int(11) NOT NULL, `project_title` varchar(100) COLLATE utf8_turkish_ci NOT NULL, `project_description` text COLLATE utf8_turkish_ci NOT NULL, `project_budget` int(11) NOT NULL, `project_allowedtime` int(11) NOT NULL, `project_deadline` datetime NOT NULL, `total_bids` int(11) NOT NULL, `average_bid` int(11) NOT NULL, `created` datetime NOT NULL, `active` tinyint(1) NOT NULL, PRIMARY KEY (`id`), KEY `created` (`created`), KEY `employer_id` (`employer_id`), KEY `active` (`active`), FULLTEXT KEY `project_title` (`project_title`,`project_description`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci AUTO_INCREMENT=3 ; CREATE TABLE IF NOT EXISTS `skills` ( `id` int(11) NOT NULL AUTO_INCREMENT, `category` int(11) NOT NULL, `name` varchar(100) COLLATE utf8_turkish_ci NOT NULL, `seo_name` varchar(100) COLLATE utf8_turkish_ci NOT NULL, `total_projects` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `seo_name` (`seo_name`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci AUTO_INCREMENT=224 ; I want to select projects with related skill names. I think i have to use JOIN but i don't know how can i do. Thanks

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• Turning on multiple result sets in an ODBC connection to SQL Server

  - by David Griffiths

  I have an application that originally needed to connect to Sybase (via ODBC), but I've needed to add the ability to connect to SQL Server as well. As ODBC should be able to handle both, I thought I was in a good position. Unfort, SQL Server will not let me, by default, nest ODBC commands and ODBCDataReaders - it complains the connection is busy. I know that I had to specify that multiple active result sets (MARS) were allowed in similar circumstances when connecting to SQL Server via a native driver, so I thought it wouldn't be an issue. The DSN wizard has no entr y when creating a SystemDSN. Some people have provided registry hacks to get around this, but this did not work (add a MARS_Connection with a value of Yes to HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI\system-dsn-name). Another suggestion was to create a file-dsn, and add "MARS_Connection=YES" to that. Didn't work. Finally, a DSN-less connection string. I've tried this one (using MultipleActiveResultSets - same variable as a Sql Server connection would use), "Driver={SQL Native Client};Server=xxx.xxx.xxx.xxx;Database=someDB;Uid=u;Pwd=p;MultipleActiveResultSets=True;" and this one: "Driver={SQL Native Client};Server=192.168.75.33\\ARIA;Database=Aria;Uid=sa;Pwd=service;MARS_Connection=YES;" I have checked the various connection-string sites - they all suggest what I've already tried.

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• Read Java in as Hex

  - by James

  Hi, I have tried to solve this but I keep coming up with stuff that is no help I'm sure this is easy (when you know how of course ;) ) What I would like to do is read in a file using a byte stream like below: while((read = in.read()) != -1){ //code removed to save space Integer.toHexString(read); System.out.println(read); } When it prints out the Hex to the screen it will print out numbers fine e.g 31 13 12 0 but when it comes to a hex code that should be 01 31 it will print 0 131. I want to read it in to a variable like you would see in a hex editor i.e 00 11 21 31 no single numbers as i need to scan the whole file and look for patterns which I know how to do I'm just stuck on this :/ so in short i need a variabe to contain the two hex characters i.e int temp = 01 not int temp = 0 , I hope this all makes sense, I'm a little confused as it's 3am! If anyone knows how to do this I would be most greatful, p.s thanks for the help in advance this site has saved me loads of research and have learnt a lot! Many thanks.

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• Is there a tool for managing redundant pages across a website?

  - by dmanexe

  I am in charge of constructing a website with a '2-dimensional' site map, as explained later. I am looking for (preferably a Wordpress plugin, as the site is built in Wordpress already) that would make managing thousands of pages a lot easier. To explain further, let me iterate my situation. I am building a website for a construction company, and they have several key cities and several key services. Now, they want a parent page for each service, and another unique page for the child sub-service, and finaly, a grandchild page for the city they are performing the service in. For example, if they were doing Concrete Construction in Los Angeles, the URL would look like: /concrete/construction/los-angeles The content on /los-angeles would be the same as on /malibu, or /burbank. However, there would be a different set of content for /concrete/design/los-angeles, but the entire page content (sans a few variables with city names) would be the same. Is there a way to manage or automate 'matrixing' this information on the site? I am looking for a tool that would allow me to easily add a 'city' with the same content across all grandchildren, per the child's content requirements. All of the grandchildren pages will have redundant content across them. Should something like this not exist, how difficult would it be to create, as a freelance side project? I need a tool like this, because I am approaching about ~500 cities and 50 services (Concrete Construction, Concrete Design, Concrete Engineering, etc)

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• In Ruby, why does a method invocation not be able to be treated as a unit when "do" and "end" is use

  - by Jian Lin

  The following question is related to http://stackoverflow.com/questions/2127836/ruby-print-inject-do-syntax The question is, can we insist on using DO and END and make it work with puts or p? This works: a = [1,2,3,4] b = a.inject do |sum, x| sum + x end puts b # prints out 10 so, is it correct to say, inject is a class method of the Array class, which takes a block of code, and then returns a number. If so, then it should be no different from calling a function and getting back a return value: b = foo(3) puts b or b = circle.getRadius() puts b In the above two cases, we can directly say puts foo(3) puts circle.getRadius() so, there is no way to make it work directly by using the following 2 ways: a = [1,2,3,4] puts a.inject do |sum, x| sum + x end but it gives ch01q2.rb:7:in `inject': no block given (LocalJumpError) from ch01q2.rb:4:in `each' from ch01q2.rb:4:in `inject' from ch01q2.rb:4 grouping the method call using ( ) doesn't work either: a = [1,2,3,4] puts (a.inject do |sum, x| sum + x end) and this gives: ch01q3.rb:4: syntax error, unexpected kDO_BLOCK, expecting ')' puts (a.inject do |sum, x| ^ ch01q3.rb:4: syntax error, unexpected '|', expecting '=' puts (a.inject do |sum, x| ^ ch01q3.rb:6: syntax error, unexpected kEND, expecting $end end) ^ finally, the following version works: a = [1,2,3,4] puts a.inject { |sum, x| sum + x } but why doesn't the grouping of the method invocation using ( ) work? What if a programmer insists that he uses do and end, can it be made to work directly with p or puts, without an extra temporary variable?

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• two controllers in one layout, rails 3

  - by Grizlord

  Okay, I have two models, a recipe model and a category model. In my layout(application.html.erb) I have a main container div that "yields" the recipes index action. I'm trying to list all the category names as links in a side bar(also a div) by iterating over them in an unordered list. When you click one of the links it will go to the category show page which will then list all the recipes in that category. Here is how I'm trying to list the links in - <div class="container" id="categories"> <% for category in @categories %> <ul> <li><%= link_to category.name, category %></li> </ul> <% end %> </div> The problem is I get a NoMethodError - You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil.each It is not retrieving the records from the model. Any suggestions on how to get this done would be greatly appreciated. I tried to render a partial as some of the other similar posts have said but still get the same error. This is the exact error - NoMethodError in Recipes#index Showing /Users/grizlord/Rails/recipe2/app/views/layouts/application.html.erb where line #39 raised: You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil.each Extracted source (around line #39): 36: </div> 37: <div class="container" id="categories"> 38: Browse by Category 39: <% for category in @categories %> 40: <ul> 41: <li><%= link_to category.name, category %></li> 42: </ul>

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• C++ destructors causing crash's

  - by larsonator

  ok, so i got a some what intricate program that simulates the uni systems of students, units, and students enrolling in units. Students are stored in a binary search tree, Units are stored in a standard list. Student has a list of Unit Pointers, to store which units he/she is enrolled in Unit has a list of Student pointers, to store students which are enrolled in that unit. The unit collections (storing units in a list) as made as a static variable where the main function is, as is the Binary search tree of students. when its finaly time to close the program, i call the destructors of each. but at some stage, during the destructors on the unit side, Unhandled exception at 0x002e4200 in ClassAllocation.exe: 0xC0000005: Access violation reading location 0x00000000. UnitCollection destructor: UnitCol::~UnitCol() { list<Unit>::iterator itr; for(itr = UnitCollection.begin(); itr != UnitCollection.end();) { UnitCollection.pop_front(); itr = UnitCollection.begin(); } } Unit Destructor Unit::~Unit() { } now i got the same sorta problem on the student side of things BST destructors void StudentCol::Destructor(const BTreeNode * r) { if(r!= 0) { Destructor(r->getLChild()); Destructor(r->getRChild()); delete r; } } StudentCol::~StudentCol() { Destructor(root); } Student Destructor Student::~Student() { } so yeah any help would be greatly appreciated

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• Linux C debugging library to detect memory corruptions

  - by calandoa

  When working sometimes ago on an embedded system with a simple MMU, I used to program dynamically this MMU to detect memory corruptions. For instance, at some moment at runtime, the foo variable was overwritten with some unexpected data (probably by a dangling pointer or whatever). So I added the additional debugging code : at init, the memory used by foo was indicated as a forbidden region to the MMU; each time foo was accessed on purpose, access to the region was allowed just before then forbidden just after; a MMU irq handler was added to dump the master and the address responsible of the violation. This was actually some kind of watchpoint, but directly self-handled by the code itself. Now, I would like to reuse the same trick, but on a x86 platform. The problem is that I am very far from understanding how is working the MMU on this platform, and how it is used by Linux, but I wonder if any library/tool/system call already exist to deal with this problem. Note that I am aware that various tools exist like Valgrind or GDB to manage memory problems, but as far as I know, none of these tools car be dynamically reconfigured by the debugged code. I am mainly interested for user space under Linux, but any info on kernel mode or under Windows is also welcome!

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• What is an elegant way to solve this max and min problem in Ruby or Python?

  - by ????

  The following can be done by step by step, somewhat clumsy way, but I wonder if there are elegant method to do it. There is a page: http://www.mariowiki.com/Mario_Kart_Wii, where there are 2 tables... there is Mario - 6 2 2 3 - - Luigi 2 6 - - - - - Diddy Kong - - 3 - 3 - 5 [...] The name "Mario", etc are the Mario Kart Wii character names. The numbers are for bonus points for: Speed Weight Acceleration Handling Drift Off-Road Mini-Turbo and then there is table 2 Standard Bike S 39 21 51 51 54 43 48 Out Bullet Bike 53 24 32 35 67 29 67 In Bubble Bike / Jet Bubble 48 27 40 40 45 35 37 In [...] These are also the characteristics for the Bike or Kart. I wonder what's the most elegant solution for finding all the maximum combinations of Speed, Weight, Acceleration, etc, and also for the minimum, either by directly using the HTML on that page or copy and pasting the numbers into a text file. Actually, in that character table, Mario to Bower Jr are all medium characters, Baby Mario to Dry Bones are small characters, and the rest are all big characters, except the small, medium, or large Mii are just as what the name says. Small characters can only ride small bike or small kart, and so forth for medium and large.

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• How is a functional programming-based javascript app laid out?

  - by user321521

  I've been working with node.js for awhile on a chat app (I know, very original, but I figured it'd be a good learning project). Underscore.js provides a lot of functional programming concepts which look interesting, so I'd like to understand how a functional program in javascript would be setup. From my understanding of functional programming (which may be wrong), the whole idea is to avoid side effects, which are basically having a function which updates another variable outside of the function so something like var external; function foo() { external = 'bar'; } foo(); would be creating a side effect, correct? So as a general rule, you want to avoid disturbing variables in the global scope. Ok, so how does that work when you're dealing with objects and what not? For example, a lot of times, I'll have a constructor and an init method that initializes the object, like so: var Foo = function(initVars) { this.init(initVars); } Foo.prototype.init = function(initVars) { this.bar1 = initVars['bar1']; this.bar2 = initVars['bar2']; //.... } var myFoo = new Foo({'bar1': '1', 'bar2': '2'}); So my init method is intentionally causing side effects, but what would be a functional way to handle the same sort of situation? Also, if anyone could point me to either a python or javascript source code of a program that tries to be as functional as possible, that would also be much appreciated. I feel like I'm close to "getting it", but I'm just not quite there. Mainly I'm interested in how functional programming works with traditional OOP classes concept (or does away with it for something different if that's the case).

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