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  • php, image dosn't show

    - by lolalola
    Hi, whats wrong with my code. image dosn't show in test2.php file File: test2.php: <img src = "test.php" /> File: test.php session_start(); $md5_hash = md5(rand(0,999)); $security_code = substr($md5_hash, 15, 5); $_SESSION["security_code"] = $security_code; $width = 100; $height = 20; header("Content-type: image/png"); $image = ImageCreate($width, $height); $white = ImageColorAllocate($image, 255, 255, 255); $black = ImageColorAllocate($image, 0, 0, 0); $grey = ImageColorAllocate($image, 204, 204, 204); ImageFill($image, 0, 0, $black); //Add randomly generated string in white to the image ImageString($image, 3, 30, 3, $security_code, $white); //Throw in some lines to make it a little bit harder for any bots to break imageRectangle($image,0,0,$width-1,$height-1,$grey); imageline($image, 0, $height/2, $width, $height/2, $grey); imageline($image, $width/2, 0, $width/2, $height, $grey); imagepng($image); imagedestroy($image);

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  • Where is mpx386.6 and start.c in Minix 3.2?

    - by John Bowlinger
    I'm trying to follow along in Operating Systems and Implementation 3rd edition and I'm now at the part in the book where Tanenbaum is discussing bootup and kernel process switching. He keeps referring to these 2 files (mpx386.s, start.c) that are supposedly in a directory called kernel, but I can't seem to find them. In the root directory, when I go to boot/minix/3.2.0/kernel, kernel just seems to be a binary file that is illegible in terminal. There also seems to be a bunch of mod01-mod12 gz binary files as well in the 3.2.0 directory. Am I in the wrong directory, or is there something I need to install and do to read kernel? I would like to follow along with the book to what's on my screen, instead of constantly flipping back and forth. I realize alot of files are completely different from this book published in 2006 and I accept that, but this seems to be a critical juncture of the book and the operating system as a whole. If it's any consolation, I'm running the OS in Virtualbox on a 64-bit Macbook.

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  • Good ways to earn income as a self employed developer

    - by nullptr
    I was just wondering if people could share their experiences and ideas about generating / earning income from a software product or service they have personally developed. To me this seems like a good way to earn a living while doing what we love (programming) and working on projects and problems which interest us. Ie, NOT boring bank or marketing software etc 9-5 all week... Some ideas I have are things like web 2.0 style sites (Facebook,Youtube,Twitter,Digg) etc etc... - These can be very very profitable as we all know but can take years to take off. Are there ways to survive until/if this does happen? Mobile applications. Iphone, Google Android and the new up coming Nintendo DS app store. These have good potential to make it easy to find a market for your application and make selling it easy. Shareware/PC software. A bit 80's and 90's and you kind of need to be a salesman/marketer to sell it but its the only other thing I can think of. Also im not talking about doing freelance work. Im only interested in idea's you can come up with and develop your self (not other peoples ideas or problems which are you are payed to develop). Things that a sole developer or at the most 2 developers could work on and have good potential for high returns on investment (in terms of time) would be great. PS, I wish I thought of stackoverflow!

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  • Why are these lines being skipped? (java)

    - by David
    Here's the relevant bit of the source code: class Dice { String name ; int x ; int[] sum ; ... public Dice (String name) { this.name = name ; this.x = 0 ; this.sum = new int[7] ; } ... public static void main (String[] arg) { Dice a1 = new Dice ("a1") ; printValues (a1) ; } public static void printDice (Dice Dice) { System.out.println (Dice.name) ; System.out.println ("value: "+Dice.x) ; printValues (Dice) ; } public static void printValues (Dice Dice) { for (int i = 0; i<Dice.sum.length; i++) System.out.println ("#of "+i+"'s: "+Dice.sum[i]) ; } } Here is the output: #of 0's: 0 #of 1's: 0 #of 2's: 0 #of 3's: 0 #of 4's: 0 #of 5's: 0 #of 6's: 0 Why didn't these two lines execute inside printDice: System.out.println (Dice.name) ; System.out.println ("value: "+Dice.x) ; if they had then i would expect to see "a1" and "Value: 0" printed at the top of the rows of #of's

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  • C++ STL Map vs Vector speed

    - by sub
    In the interpreter for my experimental programming language I have a symbol table. Each symbol consists of a name and a value (the value can be e.g.: of type string, int, function, etc.). At first I represented the table with a vector and iterated through the symbols checking if the given symbol name fitted. Then I though using a map, in my case map<string,symbol>, would be better than iterating through the vector all the time but: It's a bit hard to explain this part but I'll try. If a variable is retrieved the first time in a program in my language, of course its position in the symbol table has to be found (using vector now). If I would iterate through the vector every time the line gets executed (think of a loop), it would be terribly slow (as it currently is, nearly as slow as microsoft's batch). So I could use a map to retrieve the variable: SymbolTable[ myVar.Name ] But think of the following: If the variable, still using vector, is found the first time, I can store its exact integer position in the vector with it. That means: The next time it is needed, my interpreter knows that it has been "cached" and doesn't search the symbol table for it but does something like SymbolTable.at( myVar.CachedPosition ). Now my (rather hard?) question: Should I use a vector for the symbol table together with caching the position of the variable in the vector? Should I rather use a map? Why? How fast is the [] operator? Should I use something completely different?

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  • Why is search functionality not working on this page?

    - by DaveDev
    we deliver micro-site content for our client. Our content is injected into a wrapper that is supplied by another developer. To deliver our content we host the wrapper as well as the content. The user can access this at http://fundcentre.newireland.ie/ (try a search for 'bloxham') For the other content that is not ours, the other developer hosts a similar (though slightly different) wrapper and delivers the content. the user accesses this here: http://www.newireland.ie/ (try a search for 'bloxham') The wrapper contains a search box, which does not work for us but it works for the other developer. I took a look at the network traffic with FireBug but it appears that when I do the search from the wrapper that we're hosting, I'm getting a "407 Proxy Access Denied" error. My guess is their proxy has a problem with the fact that the search is being conducted from a page hosted outside the scope of their proxy. It was also suggested that there were javascript errors on the page that were preventing the search from executing but I can't see any. Also, I don't think I'd get as far as the proxy error if that was the case. I don't really understand this stuff too well though, so could somebody with a bit more experience please take a look and maybe shed some light on this for me? Thanks.

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  • MVC design for archived data view

    - by Hemant Tank
    Implementation of a standard archive process in ASP.Net MVC. Backend SQL Server 2005 We've an existing web app built in MVC. We've an Entity "Claim" and it has some child entities like ClaimDetails, Files, etc... A pretty standard setup in DB. Each entity has its own table and are linked via FK. Now, we need to have an "Archive" feature in web app which will allow admin to archive a Claim and its child entities. An archived Claim shud become readonly when visited again. Here're some points on which I need your valued opinion - To keep it simple and scalable (for a few million records) for now we plan to simply add a bit field "Archived" to the Claim table in db. And change the behavior accordingly in the web app. We've a 'Manage claim' page which renders a bunch of diff views for Claim and its child entities. Now, for a readonly view we can either use the same views or have a separate set of views. What do you suggest? At controller level, we can identify archived claim and select which view to render. At model level, though it'd be great to be able to use the same model used for Manage Claim - but it might not get us the "text" of some lookup fields. For example, Claim.BrandId is rendered as a dropdown in Manage claim (requires only BrandId) but for readonly view we need 'BrandText'. Any existing ref or architecture level example would be great. Here's my prev SO post but its more about db level changes: Design a process to archive data (SQL Server 2005) Thank you.

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  • Issues regarding playing audio files in a JME midlet.

    - by Northernen
    I am making a midlet which is to be used to play out local audio files. It is obviously not working. I am getting a null reference on the "is" variable, in the code snippet shown below. 1. try{ 2. System.out.println("path: " + this.getClass()); 3. InputStream is = this.getClass().getResourceAsStream("res/01Track.wav"); 4. p1=Manager.createPlayer(is, "audio"); 5. p1.realize(); 6. p1.prefetch(); 7. p1.start(); 8. } 9. catch(Exception e){ 10. System.out.println(e.getMessage()); 11. } I assume there is something wrong with the "this.getClass().getResourceAsStream("res/01Track.wav")" bit, but I can not for the life of me figure out why, and I have tried referring to the file in 20 different ways. If I printline "this.getClass()" it gives me "path: class Mp3spiller". The absolute path to "01Track.wav" is "E:\Mine dokumenter\Dokumenter\workspace_mobiljava\Mp3spiller\res\01Track.wav". Am I completely wrong in thinking that I should refer relatively to "E:\Mine dokumenter\Dokumenter\workspace_mobiljava\Mp3spiller"? If anyone could point out what I am doing wrong, I would be grateful. I have basically stolen the code from a tutorial I found online, so I would have thought it would be working.

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  • jQuery validation plugin - no error messages instead custom backgrounds

    - by Skoota
    I am using the jQuery validation plugin. The form which is being validated has custom background images for the text input fields, so instead of showing an error message for invalid fields I would like to change the background image. Making things a bit trickier is that the background image for the fields is on a different div absolutely positioned behind the text field (which has a transparent background and no border). I will spare going into the reasons for this design decision here (it's related to margins within the text field) but I thought it should be mentioned since it is critical to this question. Therefore, I have two questions: How can I stop the display of the error messages all-together? How can I instead tell the validation plugin if, for example, the name field (e.g. <input id=name ... />) is invalid then it should change the background for the relevant div (e.g. <div id=name-bg... ></div>)? Thanks for any assistance!

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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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  • Why don't I need to bind my vertex buffer object before calling glDrawArrays?

    - by valmo
    I'm a bit confused why this still renders. I thought you need to bind a vertex buffer object so that glDrawArrays knows which vertex buffer to use. Here is my initialisation code.. // Create and bind vertex array to store vertex attribute states. glGenVertexArraysOES(NUM_VERTEX_ARRAYS, &m_vertexArray); glBindVertexArrayOES(m_vertexArray); // Create and bind vertex buffer to store vertex data. glGenBuffers(NUM_VERTEX_BUFFERS, &m_vertexBuffer); glBindBuffer(GL_ARRAY_BUFFER, m_vertexBuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * 36, &m_vertices[0], GL_STATIC_DRAW); glEnableVertexAttribArray(VertexAttribPosition); glVertexAttribPointer(VertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(0)); glEnableVertexAttribArray(VertexAttribNormal); glVertexAttribPointer(VertexAttribNormal, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(12)); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArrayOES(0); Here is my render code. I'm confused why glDrawArrays still works when I bind 0 to GL_ARRAY_BUFFER. glBindVertexArrayOES(m_vertexArray); glBindBuffer(GL_ARRAY_BUFFER, 0); glDrawArrays(GL_TRIANGLES, 0, 36); glBindVertexArrayOES(0);

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  • Bizzare results when running two Visual Studio Express C++ 2008 solutions

    - by Jamie Keeling
    This is a follow on from my previous question although this is about something else. I've been having a problem where for some reason my message that I pass from one process to another only displays the first letter, in this case "M". My application based on a MSDN sample so to make sure I hadn't missed something I create a seperate solution, added the MSDN sample (Without any changes for my needs) and unsuprisingly it works fine. Now for the weird bit, when I run the MSDN sample running (As in debugging) and have my own application running, the text prints out fine without any problems. The second I run my on it's own without the original MSDN sample being open it fails to work and only shows an "M". I've looked in the debugger and don't seem to notice anything suspicious (It's a slightly dated picture, I've fixed the data type inconsistency). Can anyone provide a solution as to this? I've never encountered anything like this before. To look at my source code it's easier to just look at the link I posted at the top of the question, there's no point in me posting it twice. Thank you for any help.

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  • Expandable paragraphs with HTML and CSS

    - by user3704175
    I was wondering if anyone here would be as so kind as to help me out a bit. I am looking to make expandable paragraphs for my client's website. They would like to keep all of the content from their site, which is pretty massive, and they want a total overhaul of the design. They mainly wan tot keep it for SEO purposes. Anyhow, I thought it would be helpful for the both of use if there is some way to use expandable paragraphs, you know, with a "read more..." link after a certain line of text. I know that there are some JQuery and Java solutions for this, but we really would like to stay away from those options, if at all possible. When would like HTML and CSS, if we can. Here is kind of an example: HEADING HERE Paragraph with a bunch of text. I would like this to appear in a pre-determined line. For example, maybe the start of the paragraph goes on for, let's say, three lines and then we have the [read more...] When the visitor clicks "read more", we would like the rest of the content to just expand to reveal the article in its entirety. I would like for the content to already be on the page, so it just expands. I don't want it to be called in from another file or anything, if that makes sense. Thank you in advance for any and all help. It will be greatly appreciated! Testudo

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  • `enable_shared_from_this` has a non-virtual destructor

    - by Shtééf
    I have a pet project with which I experiment with new features of the upcoming C++0x standard. While I have experience with C, I'm fairly new to C++. To train myself into best practices, (besides reading a lot), I have enabled some strict compiler parameters (using GCC 4.4.1): -std=c++0x -Werror -Wall -Winline -Weffc++ -pedantic-errors This has worked fine for me. Until now, I have been able to resolve all obstacles. However, I have a need for enable_shared_from_this, and this is causing me problems. I get the following warning (error, in my case) when compiling my code (probably triggered by -Weffc++): base class ‘class std::enable_shared_from_this<Package>’ has a non-virtual destructor So basically, I'm a bit bugged by this implementation of enable_shared_from_this, because: A destructor of a class that is intended for subclassing should always be virtual, IMHO. The destructor is empty, why have it at all? I can't imagine anyone would want to delete their instance by reference to enable_shared_from_this. But I'm looking for ways to deal with this, so my question is really, is there a proper way to deal with this? And: am I correct in thinking that this destructor is bogus, or is there a real purpose to it?

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  • PowerPoint PlugIn does not read defaults from .dll.config file

    - by Nick T
    I'm working on a very simple PowerPoint plugin, and I'm quite a bit stumped. In my settings.settings file, I have configured a setting "StartPath", which references where the PowerPoint plugin will navigate to using a Browser component. After I compile the application, and run the installer generated by the Setup project, the application is installed and uses the default value in the settings file. However, if I edit the application.dll.config file, the plugin still uses the old values. How can I set things up such that the plugin references the .dll.config file and not its default settings? The code to access the settings is listed below, including the other variants I have tried: //Attempt 1 string location = MyApplication.Properties.Settings.Default.StartPath; //Attempt 2 string location = ConfigurationManager.AppSettings["StartPath"]; //Attempt 3: Configuration element is inaccessible due to its protection level string applicationName = Environment.GetCommandLineArgs()[0] + ".exe"; string exePath = System.IO.Path.Combine(Environment.CurrentDirectory, applicationName); Configuration config = ConfigurationManager.OpenExeConfiguration(exePath); string location = config.AppSettings["StartPath"];

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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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  • sum of square of each elements in the vector using for_each

    - by pierr
    Hi, As the function accepted by for_each take only one parameter (the element of the vector), I have to define a static int sum = 0 somewhere so that It can be accessed after calling the for_each . I think this is awkward. Any better way to do this (still use for_each) ? #include <algorithm> #include <vector> #include <iostream> using namespace std; static int sum = 0; void add_f(int i ) { sum += i * i; } void test_using_for_each() { int arr[] = {1,2,3,4}; vector<int> a (arr ,arr + sizeof(arr)/sizeof(arr[0])); for_each( a.begin(),a.end(), add_f); cout << "sum of the square of the element is " << sum << endl; } In Ruby, We can do it this way: sum = 0 [1,2,3,4].each { |i| sum += i*i} #local variable can be used in the callback function puts sum #=> 30 Would you please show more examples how for_each is typically used in practical programming (not just print out each element)? Is it possible use for_each simulate 'programming pattern' like map and inject in Ruby (or map /fold in Haskell). #map in ruby >> [1,2,3,4].map {|i| i*i} => [1, 4, 9, 16] #inject in ruby [1, 4, 9, 16].inject(0) {|aac ,i| aac +=i} #=> 30 EDIT: Thank you all. I have learned so much from your replies. We have so many ways to do the same single thing in C++ , which makes it a little bit difficult to learn. But it's interesting :)

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  • The way cores, processes, and threads work exactly?

    - by unknownthreat
    I need a bit of an advice for understanding how this whole procedure work exactly. If I am incorrect in any part described below, please correct me. In a single core CPU, it runs each process in the OS, jumping around from one process to another to utilize the best of itself. A process can also have many threads, in which the CPU core runs through these threads when it is running on the respective process. Now, on a multiple core CPU, Do the cores run in every process together, or can the cores run separately in different processes at one particular point of time? For instance, you have program A running two threads, can a duo core CPU run both threads of this program? I think the answer should be yes if we are using something like OpenMP. But while the cores are running in this OpenMP-embedded process, can one of the core simply switch to other process? For programs that are created for single core, when running at 100%, why the CPU utilization of each core are distributed? (ex. A duo core CPU of 80% and 20%. The utilization percentage of all cores always add up to 100% for this case.) Do the cores try help each other run each thread of each process in some ways? Frankly, I'm not sure how this works exactly. Any advice is appreciated.

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  • (Rails) Creating multi-dimensional hashes/arrays from a data set...?

    - by humble_coder
    Hi All, I'm having a bit of an issue wrapping my head around something. I'm currently using a hacked version of Gruff in order to accommodate "Scatter Plots". That said, the data is entered in the form of: g.data("Person1",[12,32,34,55,23],[323,43,23,43,22]) ...where the first item is the ENTITY, the second item is X-COORDs, and the third item is Y-COORDs. I currently have a recordset of items from a table with the columns: POINT, VALUE, TIMESTAMP. Due to the "complex" calculations involved I must grab everything using a single query or risk way too much DB activity. That said, I have a list of items for which I need to dynamically collect all data from the recordset into a hash (or array of arrays) for the creation of the data items. I was thinking something like the following: @h={} e = Events.find_by_sql(my_query) e.each do |event| @h["#{event.Point}"][x] = event.timestamp @h["#{event.Point}"][y] = event.value end Obviously that's not the correct syntax, but that's where my brain is going. Could someone clean this up for me or suggest a more appropriate mechanism by which to accomplish this? Basically the main goal is to keep data for each pointname grouped (but remember the recordset has them all). Much appreciated. EDIT 1 g = Gruff::Scatter.new("600x350") g.title = self.name e = Event.find_by_sql(@sql) h ={} e.each do |event| h[event.Point.to_s] ||= {} h[event.Point.to_s].merge!({event.Timestamp.to_i,event.Value}) end h.each do |p| logger.info p[1].values.inspect g.data(p[0],p[1].keys,p[1].values) end g.write(@chart_file)

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  • C++ struct, public data members and inheritance

    - by Marius
    Is it ok to have public data members in a C++ class/struct in certain particular situations? How would that go along with inheritance? I've read opinions on the matter, some stated already here http://stackoverflow.com/questions/952907/practices-on-when-to-implement-accessors-on-private-member-variables-rather-than http://stackoverflow.com/questions/670958/accessors-vs-public-members or in books/articles (Stroustrup, Meyers) but I'm still a little bit in the shade. I have some configuration blocks that I read from a file (integers, bools, floats) and I need to place them into a structure for later use. I don't want to expose these externally just use them inside another class (I actually do want to pass these config parameters to another class but don't want to expose them through a public API). The fact is that I have many such config parameters (15 or so) and writing getters and setters seems an unnecessary overhead. Also I have more than one configuration block and these are sharing some of the parameters. Making a struct with all the data members public and then subclassing does not feel right. What's the best way to tackle that situation? Does making a big struct to cover all parameters provide an acceptable compromise (I would have to leave some of these set to their default values for blocks that do not use them)?

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  • How to use Node.js to build pages that are a mix between static and dynamic content?

    - by edt
    All pages on my 5 page site should be output using a Node.js server. Most of the page content is static. At the bottom of each page, there is a bit of dynamic content. My node.js code currently looks like: var http = require('http'); http.createServer(function (request, response) { console.log('request starting...'); response.writeHead(200, { 'Content-Type': 'text/html' }); var html = '<!DOCTYPE html><html><head><title>My Title</title></head><body>'; html += 'Some more static content'; html += 'Some more static content'; html += 'Some more static content'; html += 'Some dynamic content'; html += '</body></html>'; response.end(html, 'utf-8'); }).listen(38316); I'm sure there are numerous things wrong about this example. Please enlighten me! For example: How can I add static content to the page without storing it in a string as a variable value with += numerous times? What is the best practices way to build a small site in Node.js where all pages are a mix between static and dynamic content?

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  • Pure CSS3 show/hide full height div with transition

    - by user1898838
    Dear Stackoverflow readers, I've been breaking my head over something I've seen at Tympanus, and I can't figure out how to properly do such a thing. In this link: http://tympanus.net/Tutorials/FullscreenBookBlock/ you can see that the menu is completely hidden, and only visible when you click on an icon. It has a lovely transition, and it basically roughly sums up what I'm trying to accomplish. The only difference with the above example is that I don't want to completely hide this full-height element, and I'd like to accomplish the above effect with a hover instead of having to click a button. So in an ideal world you'd see a vertical bar, and when you hover over that bar (or click on it with your finger if you're on a tablet), it "opens up" and shows you the full content inside the opened div. Now, I can make a decent bit in html5 and css3, but the above explained effect that I'm trying to accomplish has given me serious headaches, hehe. Does anyone happen to know a tutorial I might have missed that does this exact thing? p.s.: I have tried to take apart Tympanus' html/css, but with the page-fold effect that's also implemented in it I can't seem to figure it out, hence my hope for someone here to help me on my way :)

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  • drawRect gets called on UIView subclass but not on UIViewController

    - by HotFudgeSunday
    My code is working so far but I had to create a Class for the UIView. This is a bit inconvenient because I need to interact with the ViewController too. BTW, I did try [self setNeedsDisplay] on the ViewDidLoad of the UIViewController subclass file but it didn't work. Here's the code, which works on UIView Subclass but doesn't get called on a UIViewController one: - (void)drawRect:(CGRect)rect { UIColor *currentColor = [UIColor redColor]; CGContextRef context = UIGraphicsGetCurrentContext(); someNum = 1; CGContextBeginPath(context); CGContextMoveToPoint(context, 30, 40); [self addDotImageX:30 andY:40]; CGContextSetLineWidth(context, 2); CGContextSetStrokeColorWithColor(context, currentColor.CGColor); CGContextStrokePath(context); } Any ideas on what to try? BTW, this is a TabBar App. I know those can somehow block the calls to drawRect. The Tabs where created programatically, not through a Nib. Eg: NSMutableArray *listOfViewControllers = [[NSMutableArray alloc] init]; UIViewController *vc; vc = [[Education alloc] init]; vc.title = @"Education"; [listOfViewControllers addObject:vc]; vc.tabBarItem.image = [UIImage imageNamed:@"info.png"]; [vc release]; I would appreciate any ideas. I've been through the answers on this site related to setNeedsDisplay not calling drawRect and haven't found an answer for my particular case. Thanks.

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  • Best (Java) book for understanding 'under the bonnet' for programming?

    - by Ben
    What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

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  • Algorithm to pick values from set to match target value?

    - by CSharperWithJava
    I have a fixed array of constant integer values about 300 items long (Set A). The goal of the algorithm is to pick two numbers (X and Y) from this array that fit several criteria based on input R. Formal requirement: Pick values X and Y from set A such that the expression X*Y/(X+Y) is as close as possible to R. That's all there is to it. I need a simple algorithm that will do that. Additional info: The Set A can be ordered or stored in any way, it will be hard coded eventually. Also, with a little bit of math, it can be shown that the best Y for a given X is the closest value in Set A to the expression X*R/(X-R). Also, X and Y will always be greater than R From this, I get a simple iterative algorithm that works ok: int minX = 100000000; int minY = 100000000; foreach X in A if(X<=R) continue; else Y=X*R/(X-R) Y=FindNearestIn(A, Y);//do search to find closest useable Y value in A if( X*Y/(X+Y) < minX*minY/(minX+minY) ) then minX = X; minY = Y; end end end I'm looking for a slightly more elegant approach than this brute force method. Suggestions?

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