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  • Global and local variables in my script

    - by Acorn
    I'm starting out learning javascript, and tried to write a little script that would make a grid of divs on a page. Here's the script: var tileWidth=50; var tileHeight=100; var leftPos=10; var topPos=10; var columns=10; var rows=10; var spacing=5; $('document').ready(function() { placeTiles(); }); function makeRow() { for (var i=0; i<columns; i++) { $('#canvas').append('<div class="tile" style="left:' + leftPos + 'px;top:' + topPos + 'px;"></div>'); var leftPos = leftPos + tileWidth + spacing; } } function placeTiles() { for (var i=0; i<rows; i++) { makeRow(); var topPos = topPos + tileHeight + spacing; } } At the moment, 100 <div>s get created, all with a top position of 10px and a left position of undefined (for the first <div> in the row) or NaN. What should I be doing differently? Why can't makerow() see my global leftPos variable (and all the other variables for that matter)? Thanks.

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  • Loading attribute in XPATH, problem

    - by Nguyen Quoc Hung
    I've got a question about loading attribute in XPATH. I write short XML code to test: <?xml version="1.0" encoding="iso-8859-1"?> <?xml-stylesheet type="text/xsl" href="testDate.xsl"?> <element attribute="1/1/2100"> Hung </element> My XSL code: <?xml version="1.0" encoding="iso-8859-1"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <!--Handle the document: set up HTML page--> <xsl:template match="/"> <html> <head> </head> <body> This is a test <xsl:value-of select="element@attribute"/> </body> </html> </xsl:template> </xsl:stylesheet> Why it produces an error when loading the stylesheet? Would you please help me explain this? Thank you

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  • [Delphi] How would you refactor this code?

    - by Al C
    This hypothetical example illustrates several problems I can't seem to get past, even though I keep trying!! ... Suppose the original code is a long event handler, coded in the UI, triggered when a user clicks a cell in a grid. Expressed as pseudocode it's: if Condition1=true then begin //loop through every cell in row, //if aCell/headerCellValue>1 then //color aCell red end else if Condition2=true then begin //do some other calculation adding cell and headerCell values, and //if some other product>2 then //color the whole row green end else show an error message I look at this and say "Ah, refactor to the strategy pattern! The code will be easier to understand, easier to debug, and easier to later extend!" I get that. And I can easily break the code into multiple procedures. The problem is ultimately scope related. Assume the pseudocode makes extensive use of grid properties, values displayed in cells, maybe even built-in grid methods. How do you move all that to another unit, without referencing the grid component in the UI--which would break all the "rules" about loose coupling that make OOP valuable? ... I'm really looking forward to responses. Thanks, as always -- Al C.

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  • App logicstics & changes due to scope creep

    - by Kevin Brown
    I started an app that was initially a testing platform--user management, and managers that can view their employees tests. Recently, functionality has been extended (not built yet) to allow users to complete a test in place of an employee--basically adding a record, but no user. I have three tables in use for this: users(contains user info for login/security), profiles (all personal info: address, height, etc.), and survey (contains survey answers for user). How do I extend my application to encompass this functionality with minimal change to the structure? I assume that the best way to do this would be to insert records to the tables profiles and survey, and have no username/password/email? There MUST be a user_id associated b/c the tables are linked through the user_ids...

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  • Should I add try/catch around when casting on an attribute of JSP implicit object?

    - by Michael Mao
    Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

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  • Asp.net webservices

    - by Patel
    Hi everyone, I am new to asp.net .. i want to learn about web services.. can anyone pls provide me a good link or pdf on web services for reading it from basic.. thanks in advance..

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  • jquery tooltip shows a div's content

    - by bob
    Hello, I want to use either http://onehackoranother.com/projects/jquery/tipsy/ or http://bassistance.de/jquery-plugins/jquery-plugin-tooltip/ and I was wondering if lets say I have a div on my page that has a class 'item_info'. Can I have my tooltip that is created output the div inside the tooltip and formatted properly according to my css? Is there another plugin I should be looking into? Thanks. I hope this is clear enough.

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  • C# Proxy, what is the best way to do this?

    - by Kin
    I'm writing a proxy using .NET and C#. It has a couple of functions that it needs to fulfill. I haven't done much Socket programming, and I am not sure the best way to go about it. Should I use Synchronous Sockets, Asynchronous sockets? Please help! It must... Accept Connections from the client on two different ports, and be able to receive data on both ports at the same time. When a connection is made on a port, it must immediately connect to the server, and start sending data as it receives it from the client to the server. Packets must be forwarded in the order they are received, exactly as they were received. It needs to be as low latency as possible. I don't need the ability for multiple clients to use the proxy, but it would be a nice feature if its easy to implement.

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  • Using GA in GUI

    - by AlexT
    Sorry if this isn't clear as I'm writing this on a mobile device and I'm trying to make it quick. I've written a basic Genetic Algorithm with a binary encoding (genes) that builds a fitness value and evolves through several iterations using tournament selection, mutation and crossover. As a basic command-line example it seems to work. The problem I've got is with applying a genetic algorithm within a GUI as I am writing a maze-solving program that uses the GA to find a method through a maze. How do I turn my random binary encoded genes and fitness function (add all the binary values together) into a method to control a bot around a maze? I have built a basic GUI in Java consisting of a maze of labels (like a grid) with the available routes being in blue and the walls being in black. To reiterate my GA performs well and contains what any typical GA would (fitness method, get and set population, selection, crossover, etc) but now I need to plug it into a GUI to get my maze running. What needs to go where in order to get a bot that can move in different directions depending on what the GA says? Rough pseudocode would be great if possible As requested, an Individual is built using a separate class (Indiv), with all the main work being done in a Pop class. When a new individual is instantiated an array of ints represent the genes of said individual, with the genes being picked at random from a number between 0 and 1. The fitness function merely adds together the value of these genes and in the Pop class handles selection, mutation and crossover of two selected individuals. There's not much else to it, the command line program just shows evolution over n generations with the total fitness improving over each iteration. EDIT: It's starting to make a bit more sense now, although there are a few things that are bugging me... As Adamski has suggested I want to create an "Agent" with the options shown below. The problem I have is where the random bit string comes into play here. The agent knows where the walls are and has it laid out in a 4 bit string (i.e. 0111), but how does this affect the random 32 bit string? (i.e. 10001011011001001010011011010101) If I have the following maze (x is the start place, 2 is the goal, 1 is the wall): x 1 1 1 1 0 0 1 0 0 1 0 0 0 2 If I turn left I'm facing the wrong way and the agent will move completely off the maze if it moves forward. I assume that the first generation of the string will be completely random and it will evolve as the fitness grows but I don't get how the string will work within a maze. So, to get this straight... The fitness is the result of when the agent is able to move and is by a wall. The genes are a string of 32 bits, split into 16 sets of 2 bits to show the available actions and for the robot to move the two bits need to be passed with four bits from the agent showings its position near the walls. If the move is to go past a wall the move isn't made and it is deemed invalid and if the move is made and if a new wall is found then the fitness goes up. Is that right?

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  • Problems with rails and saving to the database.

    - by Grantismo
    I've been having some difficulty in understanding the source of a problem. Below is a listing of the model classes. Essentially the goal is to have the ability to add sentences to the end of the story, or to add stories to an existing sentence_block. Right now, I'm only attempting to allow users to add sentences, and automatically create a new sentence_block for the new sentence. class Story < ActiveRecord::Base has_many :sentence_blocks, :dependent => :destroy has_many :sentences, :through => :sentence_blocks accepts_nested_attributes_for :sentence_blocks end class SentenceBlock < ActiveRecord::Base belongs_to :story has_many :sentences, :dependent => :destroy end class Sentence < ActiveRecord::Base belongs_to :sentence_block def story @sentence_block = SentenceBlock.find(self.sentence_block_id) Story.find(@sentence_block.story_id) end end The problem is occurring when using the show method of the Story. The Story method is as follows, and the associated show method for a sentence is also included. Sentence.show def show @sentence = Sentence.find(params[:id]) respond_to do |format| format.html {redirect_to(@sentence.story)} format.xml { render :xml => @sentence } end end Story.show def show @story = Story.find(params[:id]) @sentence_block = @story.sentence_blocks.build @new_sentence = @sentence_block.sentences.build(params[:sentence]) respond_to do |format| if @new_sentence.content != nil and @new_sentence.sentence_block_id != nil and @sentence_block.save and @new_sentence.save flash[:notice] = 'Sentence was successfully added.' format.html # new.html.erb format.xml { render :xml => @story } else @sentence_block.destroy format.html format.xml { render :xml => @story } end end end I'm getting a "couldn't find Sentence_block without and id" error. So I'm assuming that for some reason the sentence_block isn't getting saved to the database. Can anyone help me with my understanding of the behavior and why I'm getting the error? I'm trying to ensure that every time the view depicts show for a story, an unnecessary sentence_block and sentence isn't created, unless someone submits the form, I'm not really sure how to accomplish this. Any help would be appreciated.

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  • How to make a php function contain mysql commands

    - by bob
    I want to create a simple menu function which can call it example get_menu() Here is my current code. <?php $select = 'SELECT * FROM pages'; $query = $db->rq($select); while ($page = $db->fetch($query)) { $id = $page['id']; $title = $page['title']; ?> <a href="page.php?id<?php echo $id; ?>" title="<?php echo $title; ?>"><?php echo $title; ?></a> <?php } ?> How to do that in? function get_menu() { } Let me know.

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  • Condensing multiple else if statements, referencing them from a table?

    - by Haskella
    Hi I'm about to type some 500 else if statements into my code (PHP) which have the exact same coding each: if (color=White); rgb = 255-255-255; print rgb; else if (color=Black); rgb = 0-0-0; print rgb; else if (color=Red); rgb = 255-0-0; print rgb; else if (color=Blue); rgb = 0-0-255; print rgb; [the list keeps going] I also (luckily) have a table that displays the color in the first column and rgb value in the next column for 500 of them... how do I use this to save time typing all those else if statements? Some how I have to reference the table file (made in excel, I'm guessing I'll have to save it as .csv?)

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  • How to share a variable between two classes?

    - by Altefquatre
    How would you share the same object between two other objects? For instance, I'd like something in that flavor: class A { private string foo_; // It could be any other class/struct too (Vector3, Matrix...) public A (string shared) { this.foo_ = shared; } public void Bar() { this.foo_ = "changed"; } } ... // inside main string str = "test"; A a = new A(str); Console.WriteLine(str); // "test" a.Bar(); Console.WriteLine(str); // I get "test" instead of "changed"... :( I read there is some ref/out stuff, but I couldn't get what I'm asking here. I could only apply some changes in the methods scope where I was using ref/out arguments... I also read we could use pointers, but is there no other way to do it?

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  • My Ruby Code: How can I improve? (Java to Ruby guy)

    - by steve
    Greetings, I get the feeling that I'm using ruby in an ugly way and possibly missing out on tonnes of useful features. I was wondering if anyone could point out a cleaner better way to write my code which is pasted here. The code itself simply scrapes some data from yelp and processes it into a json format. The reason I'm not using hash.to_json is because it throws some sort of stack error which I can only assume is due to the hash being too large (It's not particularly large). Response object = a hash text = the output which saves to file Anyways guidance appreciated. def mineLocation client = Yelp::Client.new request = Yelp::Review::Request::GeoPoint.new(:latitude=>13.3125,:longitude => -6.2468,:yws_id => 'nicetry') response = client.search(request) response['businesses'].length.times do |businessEntry| text ="" response['businesses'][businessEntry].each { |key, value| if value.class == Array value.length.times { |arrayEntry| text+= "\"#{key}\":[" value[arrayEntry].each { |arrayKey,arrayValue| text+= "{\"#{arrayKey}\":\"#{arrayValue}\"}," } text+="]" } else text+="\"#{arrayKey}\":\"#{arrayValue}\"," end } end end

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  • Tutorial/resource for implementing VM

    - by zaharpopov
    Hello, I want self-education purpose implement a simple virtual machine for a dynamic language, prefer in C language. Something like the Lua VM, or Parrot, or Python VM, but simpler. Are there any good resources/tutorials on achieving this, apart from looking at code and design documentations of the existing VMs? Thanks in advance for your answers and ideas Edit: why close vote? I don't understand - is this not programming. Please comment if there is specific problem with my question.

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  • Network Security and Encryption explained in laymen terms

    - by Ehrann Mehdan
    Although I might pretend very well that I known a thing about networks or security and it might help me pass an interview, or fix a bug, I don't really feel I'm fooling anyone. I'm looking for a laymen terms explanation of nowadays network security concepts and solutions. The information is scattered around and I didn't find a resource for "dummies" like me (e.g experienced Java developers that can speak the jargon but have no real clue what it means) Topics I have a weak notion about and want to understand better as a Java developer PGP Public / Private keys RSA / DES SSL and 2 way SSL (keystore / trustore) Protecting against Man in the middle fraud Digital Signature and Certificates Is there a resource out there that really explains it in a way that doesn't require a Cisco certificate / Linux lingo / know what is subnet masking or other plumbing skills?

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  • What is the typical method to separate connected letters in a word using OCR

    - by Maysam
    I am very new to OCR and almost know nothing about the algorithms used to recognize words. I am just getting familiar to that. Could anybody please advise on the typical method used to recognize and separate individual characters in connected form (I mean in a word where all letters are linked together)? Forget about handwriting, supposing the letters are connected together using a known font, what is the best method to determine each individual character in a word? When characters are written separately there is no problem, but when they are joined together, we should know where every single character starts and ends in order to go to the next step and match them individually with a letter. Is there any known algorithm for that?

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  • Is using the break statement bad practice?

    - by Lchi
    I've been told by professors and peers at my university that using the break statement is bad practice, but through my coursework haven't come up with a great reason why. Those who claim that it is bad say that it's a "get out of jail free card" and that you can always avoid using it. My guesses for why its considered bad would be that you could possibly skip some cleanup code after the break, or similarly exit some control structure in an inconsistent state. Is there any reason why using break is(n't) bad practice?

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