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  • django simple approach to multi-field search

    - by Scott Willman
    I have a simple address book app that I want to make searchable. The model would look something like: class Address(models.Model): address1 = models.CharField("Address Line 1", max_length=128) address2 = models.CharField("Address Line 2", max_length=128) city = models.CharField("City", max_length=128) state = models.CharField("State", max_length=24) zipCode = models.CharField("Zip Code", max_length=24) def __unicode__(self): return "%s %s, %s, %s, %s" % (self.address1, self.address2, self.city, self.state, self.zipCode) class Entry(models.Model): name = models.CharField("Official School Name", max_length=128) createdBy = models.ForeignKey(User) address = models.ForeignKey(Address, unique=True) def __unicode__(self): return "%s - %s, %s" % (self.name, self.address.city, self.address.state) I want the searching to be fairly loose, like: Bank of America Los Angeles 91345. It seems like I want a field that contains all of those elements into one that I can search, but that also seems redundant. I was hoping I could add a method to the Entry model like this: def _getSearchText(self): return "%s %s %s" % (self.name, self.address, self.mascot) searchText = property(_getSearchText) ...and search that as a field, but I suppose that's wishful thinking... How should I approach this using basic Django and SqLite (this is a learning exercise). Thank you!!

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  • Conditional column values in NSTableView?

    - by velocityb0y
    I have an NSTableView that binds via an NSArrayController to an NSMutableArray. What's in the array are derived classes; the first few columns of the table are bound to properties that exist on the base class. That all works fine. Where I'm running into problem is a column that should only be populated if the row maps to one specific subclass. The property that column is meant to display only exists in that subclass, since it makes no sense in terms of the base class. The user will know, from the first two columns, why the third column's cell is populated/editable or not. The binding on the third column's value is on arrangedObjects, with a model path of something like "foo.name" where foo is the property on the subclass. However, this doesn't work, as the other subclasses in the hierarchy are not key-value compliant for foo. It seems like my only choice is to have foo be a property on the base class so everybody responds to it, but this clutters up the interfaces of the model objects. Has anyone come up with a clean design for this situation? It can't be uncommon (I'm a relative newcomer to Cocoa and I'm just learning the ins and outs of bindings.)

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  • Duplicate Symbol Linker Error (C++ help)

    - by Vash265
    Hi. I'm learning some CSP (constraint satisfaction) theory stuff right now, and am using this library to parse XML files. I'm using Xcode as an IDE. My program compiles fine, but when it goes to link the files, I get a duplicate symbol error with the XMLParser_libxml2.hh file. My files are separated as such: A class header file that includes the XMLParser file above A class implementation file that include the class header file A main file that includes the class header file The duplicate symbol is occurring in main.o and classfile.o, but as far as I can tell, I'm not actually adding that .hh file twice. Full error: ld: duplicate symbol bool CSPXMLParser::UTF8String::to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::basic_string<char, std::char_traits<char>, std::allocator<char> >&) constin /Users/vash265/CSP/Untitled/build/Untitled.build/Debug/Untitled.build/Objects-normal/x86_64/dStructFill.o and /Users/vash265/CSP/Untitled/build/Untitled.build/Debug/Untitled.build/Objects-normal/x86_64/main.o Copying the implementation of the class into the main file and taking the class implementation file out of the compilation target alleviates the error, but it's a disorganized mess this way, and I'll be adding more classes very soon (and it would be nice to have them in separate files). As I've come to understand it, this is caused by the file (XMLParser_libxml2.hh) having both the class and function definition and implementation in one file (and it seems as though this might have been necessary due to the use of templates in that 'header' file). Any ideas on how to get around sticking all my class files in my main.cpp? (I've tried ifdefs, they don't work).

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  • FragmentActivity cannot be resolve to a type

    - by Pratik
    I am starting learning for android tablet programming and I am able to updated my Eclipse as well as all new sdk for android. I have start testing application from this blog while at extending the FragmentActivity getting this error I have google it but not getting any solution. My project was created with 3.0 version having 11 level, all other packages are successfully used in the code but only this FragmentActivity was not able to resolve. Am I missing any library or any thing? My code public class Testing_newActivity extends FragmentActivity { // here the FragmentActivity getting error package not found for import /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //setContentView(R.layout.main); if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) { // If the screen is now in landscape mode, we can show the // dialog in-line so we don't need this activity. finish(); return; } if (savedInstanceState == null) { // During initial setup, plug in the details fragment. DetailsFragment details = new DetailsFragment(); details.setArguments(getIntent().getExtras()); getSupportFragmentManager().beginTransaction().add( android.R.id.content, details).commit(); } } } android manifest file <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.searce.testingnew" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="11" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:label="@string/app_name" android:name=".Testing_newActivity" > <intent-filter > <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>

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  • Wnat is the preferred method of building extremely lightweight business object / DAL now that I have

    - by Seth Spearman
    Hello, I have completed a simple database for a project. Only 6tables. Of the 6, one is a "lookup" table. There is one "master" table that is the driver for the system. It is referenced as a foreign key by the other four tables. Give that this step is completed. What is the FASTEST, EASIEST way to create POCOs/BizObjects that can load load the data and the child data. Here are my CAVEATS. *I don't want to spend more than 30-60 minutes learning how? *There is very little biz logic needed in the POCOs. They will pretty much load data. Don't even really need to write back data. *I already know CSLA (up to version 3) but I feel that is overkill for this little project. *Nevertheless, I would love it if it ROOT objects could have collection classes that contain the CHILD objects as in CSLA...but again, without using CSLA. *Please give the answer for .NET 35 but also if I was restricted to only use .NET 20. *Ideally I could just point a tool at the database and the POCOs would be genn'ed. *FREE Just curious what you guys use for this kind of scenario. I understand that this question is subjective but I want to hear a variety of answers. Seth

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  • Javascript JQUERY AJAX: When Are These Implemented

    - by Michael Moreno
    I'm learning javascript. Poked around this excellent site to gather intel. Keep coming across questions / answers about javascript, JQUERY, JQUERY with AJAX, javascript with JQUERY, AJAX alone. My conclusion: these are all individually powerful and useful. My confusion: how does one determine which/which combination to use ? I've concluded that javascript is readily available on most browsers. For example, I can extend a simple HTML page with <html> <body> <script type="text/javascript"> document.write("Hello World!"); </script> </body> </html> However, within the scope of Python/DJANGO, many of these questions are JQUERY and AJAX related. At which point or under what development circumstances would I conclude that javascript alone isn't going to "cut it", and I need to implement JQUERY and/or AJAX and/or some other permutation ?

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  • I getting undefined using JSON in jQuery why?

    - by YoniGeek
    Im learning some JSON, Im trying to list some data about dogs from twitter...but I can't really present the data...I believe that the error is inside map-method...something I'm missing...thanks for yr help <body> <h1>U almost there!!</h1> <script src="jquery-1.7.1.js"> </script> <script> // PubSub (function( $ ) { var o = $( {} ); $.each({ trigger: 'publish', on: 'subscribe', off: 'unsubscribe' }, function( key, val ) { jQuery[val] = function() { o[key].apply( o, arguments ); }; }); })( jQuery ); $.getJSON('http://search.twitter.com/search.json?q=dogs&callback=?', function( info) { $.publish( 'twitter/info', info ); }); // ... $.subscribe( 'twitter/info', function( e, info ) { $('body').html( $.map( info, function( obj) { // <--- here it's error, something Im missing right? return '<li>' + obj.text + '</li>'; }).join('') ); }); </script> </body> </html>

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  • How do I debug JavaScript .onlick event?

    - by user3700824
    I'm learning JavaScript but seem to be having a problem. I have a piece of code that is executed when the page is fully loaded. The function then gathers all the button elements on my HTML page. From here I loop through getting each button's title attribute and then assign an onclick event to the button that is equal to a function that writes to the console.log with the title. I have tried various ways of doing this but it is not working. Here is the JavaScript code that I'm working with. Currently all it does is loop through calling the function and logging the tile to the console.log, but this is not supposed to happen. Each time I click the button it should call the function with its title and log that. window.onload = myPageIsReady; function myPageIsReady(){ var myList = document.getElementsByTagName("button"); var myTitle = []; for(var i = 0; i < myList.length; i++){ myTitle[i] = myList[i].getAttribute("title"); myList[i].onclick = getMyTitle(myTitle[i]); }; function getMyTitle(myTitle){ console.log(myTitle); }; };

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  • How can I bind a List as ItemSource to ListView in XAML?

    - by Jonas
    I'm learning WPF and would like to have a collection similar to a LinkedList, to where I can add and remove strings. And I want to have a ListView that listen to that collection with databinding. How can I do bind a simple list collection to a ListView in XAML? My idea (not working) is something like this: <Window x:Class="TestApp.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Window.Resources> <LinkedList x:Key="myList"></LinkedList> //Wrong <Window.Resources> <Grid> <ListView Height="100" HorizontalAlignment="Left" Margin="88,134,0,0" Name="listView1" VerticalAlignment="Top" Width="120" ItemsSource="{Binding Source={StaticResource myList}}"/> //Wrong </Grid> </Window> All my code (updated version, not working): <Window x:Class="TestApp.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <TextBox Height="23" HorizontalAlignment="Left" Margin="12,12,0,0" Name="textBox1" VerticalAlignment="Top" Width="120" /> <Button Content="Button" Height="23" HorizontalAlignment="Right" Margin="0,12,290,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" /> <ListView Height="100" HorizontalAlignment="Left" Margin="88,134,0,0" Name="listView1" VerticalAlignment="Top" Width="120" ItemsSource="{Binding myList}"/> </Grid> </Window> C#-code: namespace TestApp { public partial class MainWindow : Window { ObservableCollection<string> myList = new ObservableCollection<string>(); public MainWindow() { InitializeComponent(); myList.Add("first string"); } private void button1_Click(object sender, RoutedEventArgs e) { myList.Add(textBox1.Text); textBox1.Text = myList.Count+"st"; } } }

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  • How would I go about sharing variables in a C++ class with Lua?

    - by Nicholas Flynt
    I'm fairly new to Lua, I've been working on trying to implement Lua scripting for logic in a Game Engine I'm putting together. I've had no trouble so far getting Lua up and running through the engine, and I'm able to call Lua functions from C and C functions from Lua. The way the engine works now, each Object class contains a set of variables that the engine can quickly iterate over to draw or process for physics. While game objects all need to access and manipulate these variables in order for the Game Engine itself to see any changes, they are free to create their own variables, a Lua is exceedingly flexible about this so I don't forsee any issues. Anyway, currently the Game Engine side of things are sitting in C land, and I really want them to stay there for performance reasons. So in an ideal world, when spawning a new game object, I'd need to be able to give Lua read/write access to this standard set of variables as part of the Lua object's base class, which its game logic could then proceed to run wild with. So far, I'm keeping two separate tables of objects in place-- Lua spawns a new game object which adds itself to a numerically indexed global table of objects, and then proceeds to call a C++ function, which creates a new GameObject class and registers the Lua index (an int) with the class. So far so good, C++ functions can now see the Lua object and easily perform operations or call functions in Lua land using dostring. What I need to do now is take the C++ variables, part of the GameObject class, and expose them to Lua, and this is where google is failing me. I've encountered a very nice method here which details the process using tags, but I've read that this method is deprecated in favor of metatables. What is the ideal way to accomplish this? Is it worth the hassle of learning how to pass class definitions around using libBind or some equivalent method, or is there a simple way I can just register each variable (once, at spawn time) with the global lua object? What's the "current" best way to do this, as of Lua 5.1.4?

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  • jQuery: show an element from select drop down, hide it when other option selected

    - by Ricardo Zea
    I've tried looking around and there are similar problems, but mine is way more simple, but yet, I can't find a solution within these forums. While learning jQuery, I'm trying to show a DIV when an item/option from a select drop down is selected, and hide that same DIV when any other option in the select drop down is selected. select HTML: <select name="source" id="source"> <option value="null" selected="selected">&mdash;Select&mdash;</option> <option value="s1">Source 1</option> <option value="s2">Source 2</option> <option value="sother">Other</option> </select> DIV I need to show when 'Other' is selected: <div id="specify-source">Other source here...</div> When any other option in the select menu is selected, the above DIV shouldn't be visible. I've tried this jQuery but of course it doesn't work properly: $(function() { $.viewMap = { 'sother' : $('#specify-source') }; $('#source').change(function() { // hide all $.each($.viewMap, function() { this.hide(); }); // show current $.viewMap[$(this).val()].show(); }); }); Any help you can give me, I'd greatly appreciate it. Thanks,

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  • Android - Parsing XML with XPath

    - by Ruben Deig Ramos
    First of all, thanks to all the people who's going to spend a little time on this question. Second, sorry for my english (not my first language! :D). Well, here is my problem. I'm learning Android and I'm making an app which uses a XML file to store some info. I have no problem creating the file, but trying to read de XML tags with XPath (DOM, XMLPullParser, etc. only gave me problems) I've been able to read, at least, the first one. Let's see the code. Here is the XML file the app generates: <dispositivo> <id>111</id> <nombre>Name</nombre> <intervalo>300</intervalo> </dispositivo> And here is the function which reads the XML file: private void leerXML() { try { XPathFactory factory=XPathFactory.newInstance(); XPath xPath=factory.newXPath(); // Introducimos XML en memoria File xmlDocument = new File("/data/data/com.example.gps/files/devloc_cfg.xml"); InputSource inputSource = new InputSource(new FileInputStream(xmlDocument)); // Definimos expresiones para encontrar valor. XPathExpression tag_id = xPath.compile("/dispositivo/id"); String valor_id = tag_id.evaluate(inputSource); id=valor_id; XPathExpression tag_nombre = xPath.compile("/dispositivo/nombre"); String valor_nombre = tag_nombre.evaluate(inputSource); nombre=valor_nombre; } catch (Exception e) { e.printStackTrace(); } } The app gets correctly the id value and shows it on the screen ("id" and "nombre" variables are assigned to a TextView each one), but the "nombre" is not working. What should I change? :) Thanks for all your time and help. This site is quite helpful! PD: I've been searching for a response on the whole site but didn't found any.

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  • Cryptic Erlang Errors

    - by Jim
    Okay so I started learning erlang recently but am baffled by the errors it keeps returning. I made a bunch of changes but I keep getting errors. The syntax is correct as far as I can tell but clearly I'm doing something wrong. Have a look... -module(pidprint). -export([start/0]). dostuff([]) - receive begin - io:format("~p~n", [This is a Success]) end. sender([N]) - N ! begin, io:format("~p~n", [N]). start() - StuffPid = spawn(pidprint, dostuff, []), spawn(pidprint, sender, [StuffPid]). Basically I want to compile the script, call start, spawn the "dostuff" process, pass its process identifier to the "sender" process, which then prints it out. Finally I want to send a the atom "begin" to the "dostuff" process using the process identifier initially passed into sender when I spawned it. The errors I keep getting occur when I try to use c() to compile the script. Here they are.. ./pidprint.erl:6: syntax error before: '-' ./pidprint.erl:11: syntax error before: ',' What am I doing wrong?

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  • Resources and techniques/methods for SCJP preparation ?

    - by BenoitParis
    I am passing the SCJP 6 exam in a month. I have the "SCJP Sun Certified Programmer for Java 6 Exam 310-065" book. It seems great for the exam. But I want your advice on this. Getting the closest possible to 100% would be great. I have found a site that answered some of the questions you ask yourself when you go trough the book. Here is it : http://www.janeg.ca/java2.html As you can see it was written for Java 2 :/ I have written another specific question here on StackOverflow about the usefulness of JVM specification and Java compiler code for the SCJP. Will Update the results here. Here it is. Please share the resources you used in preparing the exam. Please also specify any resources that you think might help. Any type of resource is welcome: books, code, specs, sites, wikies, papers, online tests, grandmas... Please also share on any method/technique that helped you prepare the exam. Please also comment on the return you got from the resource and the method (for the learning process and for points in the exam) I'll begin: Book : "SCJP Sun Certified Programmer for Java 6 Exam 310-065". Seems like the official book for the preparation. Technique : Writing code in a text editor and compiling it with javac to test a question. NO IDEs! It helps you get a a straight answer to a question you have. It helps you pay attention to every word in the code (and this is very important in the SCJP) EDIT: Added dimension: Are there good, up-to-date online tests?

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  • Is XSLT worth investing time in and are there any actual alternatives?

    - by Keeno
    I realize this has been a few other questions on this topic, and people are saying use your language of choice to manipulate the XML etc etc however, not quite fit my question exactly. Firstly, the scope of the project: We want to develop platform independent e-learning, currently, its a bunch of HTML pages but as they grow and develop they become hard to maintain. The idea: Generate up an XML file + Schema, then produce some XSLT files that process the XML into the eLearning modiles. XML to HTML via XSLT. Why: We would like the flexibilty to be able to easy reformat the content (I realize CSS is a viable alternative here) If we decide to alter the pages layout or functionality in anyway, im guessing altering the "shared" XSLT files would be easier than updating the HTML files. So far, we have about 30 modules, with up to 10-30 pages each Depending on some "parameters" we could output drastically different page layouts/structures, above and beyond what CSS can do Now, all this has to be platform independent, and to be able to run "offline" i.e. without a server powering the HTML Negatives I've read so far for XSLT: Overhead? Not exactly sure why...is it the compute power need to convert to HTML? Difficult to learn Better alternatives Now, what I would like to know exactly is: are there actually any viable alternatives for this "offline"? Am I going about it in the correct manner, do you guys have any advice or alternatives. Thanks!

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  • App crashes every second time a tableview row is selected in navigation controller setup

    - by Thaurin
    Disclaimer first: I'm pretty new to Objective-C and the retain model. I've been developing in a garbage collected .NET environment for the last five years, so I've been spoiled. I'm still learning. I'm having my iPhone app crash with EXC_BAD_ACCESS. It happens in a navigtation controller/tableview setup. When I select a row the first time, no problems. It switches in the child controller without problems. I go back and select the same row again. Program then proceeds to crash. Every other row works fine, but every second time a row is accessed, it's a crash. I've pinpointed the location where this happens. The child controller (which is a class that I reuse for every row of the same type) that's being switched into has an array of NSString's representing the rows that will be displayed. I set it before pushing the child viewcontroller. It's there where this apparently happens. I'm having a hard time debugging this problem, still wrestling with xcode and all. I fear there may be some vital information missing here, but maybe there is something you recognize here.

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  • CodeIgniter and SimpleTest -- How to make my first test?

    - by Smandoli
    I'm used to web development using LAMP, PHP5, MySQL plus NetBeans with Xdebug. Now I want to improve my development, by learning how to use (A) proper testing and (B) a framework. So I have set up CodeIgniter, SimpleTest and the easy Xdebug add-in for Firefox. This is great fun because maroonbytes provided me with clear instructions and a configured setup ready for download. I am standing on the shoulders of giants, and very grateful. I've used SimpleTest a bit in the past. Here is a the kind of thing I wrote: <?php require_once('../simpletest/unit_tester.php'); require_once('../simpletest/reporter.php'); class TestOfMysqlTransaction extends UnitTestCase { function testDB_ViewTable() { $this->assertEqual(1,1); // a pseudo-test } } $test = new TestOfMysqlTransaction(); $test->run(new HtmlReporter()) ?> So I hope I know what a test looks like. What I can't figure out is where and how to put a test in my new setup. I don't see any sample tests in the maroonbytes package, and Google so far has led me to posts that assume unit testing is already functionally available. What do I do?

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  • My QFileSystemModel doesn't work as expected in PyQt

    - by Skilldrick
    I'm learning the Qt Model/View architecture at the moment, and I've found something that doesn't work as I'd expect it to. I've got the following code (adapted from Qt Model Classes): from PyQt4 import QtCore, QtGui model = QtGui.QFileSystemModel() parentIndex = model.index(QtCore.QDir.currentPath()) print model.isDir(parentIndex) #prints True print model.data(parentIndex).toString() #prints name of current directory childIndex = model.index(0, 0, parentIndex) print model.data(childIndex).toString() rows = model.rowCount(parentIndex) print rows #prints 0 (even though the current directory has directory and file children) The question: Is this a problem with PyQt, have I just done something wrong, or am I completely misunderstanding QFileSystemModel? According to the documentation, model.rowCount(parentIndex) should return the number of children in the current directory. The QFileSystemModel docs say that it needs an instance of a Gui application, so I've also placed the above code in a QWidget as follows, but with the same result: import sys from PyQt4 import QtCore, QtGui class Widget(QtGui.QWidget): def __init__(self, parent=None): QtGui.QWidget.__init__(self, parent) model = QtGui.QFileSystemModel() parentIndex = model.index(QtCore.QDir.currentPath()) print model.isDir(parentIndex) print model.data(parentIndex).toString() childIndex = model.index(0, 0, parentIndex) print model.data(childIndex).toString() rows = model.rowCount(parentIndex) print rows def main(): app = QtGui.QApplication(sys.argv) widget = Widget() widget.show() sys.exit(app.exec_()) if __name__ == '__main__': main()

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  • Why initialize an object to empty

    - by ProgEnthu
    I am learning windows programming with the help of MSDN.Why would somebody initialize an object like the following? WNDCLASS wc = { }; Will this zero all the memory of the object? Whole source code is following: #ifndef UNICODE #define UNICODE #endif #include <windows.h> LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam); int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow) { // Register the window class. const wchar_t CLASS_NAME[] = L"Sample Window Class"; WNDCLASS wc = { }; wc.lpfnWndProc = WindowProc; wc.hInstance = hInstance; wc.lpszClassName = CLASS_NAME; RegisterClass(&wc); // Create the window. HWND hwnd = CreateWindowEx( 0, // Optional window styles. CLASS_NAME, // Window class L"Learn to Program Windows", // Window text WS_OVERLAPPEDWINDOW, // Window style // Size and position CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, // Parent window NULL, // Menu hInstance, // Instance handle NULL // Additional application data ); if (hwnd == NULL) { return 0; } ShowWindow(hwnd, nCmdShow); // Run the message loop. MSG msg = { }; while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return 0; } LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch (uMsg) { case WM_DESTROY: PostQuitMessage(0); return 0; case WM_PAINT: { PAINTSTRUCT ps; HDC hdc = BeginPaint(hwnd, &ps); FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1)); EndPaint(hwnd, &ps); } return 0; } return DefWindowProc(hwnd, uMsg, wParam, lParam); }

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  • javascript split() array contains

    - by Mahesha999
    While learning JavaScript, I did not get why the output when we print the array returned of the Sting.split() method (with regular expression as an argument) is as explained below. var colorString = "red,blue,green,yellow"; var colors = colorString.split(/[^\,]+/); document.write(colors); //this print 7 times comma: ,,,,,,, However when I print individual element of the array colors, it prints an empty string, three commas and an empty string: document.write(colors[0]); //empty string document.write(colors[1]); //, document.write(colors[2]); //, document.write(colors[3]); //, document.write(colors[4]); //empty string document.write(colors[5]); //undefined document.write(colors[6]); //undefined Then, why printing the array directly gives seven commas. Though I think its correct to have three commas in the second output, I did not get why there is a starting (at index 0) and ending empty string (at index 4). Please explain I am screwed up here.

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  • Prove correctness of unit test

    - by Timo Willemsen
    I'm creating a graph framework for learning purposes. I'm using a TDD approach, so I'm writing a lot of unit tests. However, I'm still figuring out how to prove the correctness of my unit tests For example, I have this class (not including the implementation, and I have simplified it) public class SimpleGraph(){ //Returns true on success public boolean addEdge(Vertex v1, Vertex v2) { ... } //Returns true on sucess public boolean addVertex(Vertex v1) { ... } } I also have created this unit tests @Test public void SimpleGraph_addVertex_noSelfLoopsAllowed(){ SimpleGraph g = new SimpleGraph(); Vertex v1 = new Vertex('Vertex 1'); actual = g.addVertex(v1); boolean expected = false; boolean actual = g.addEdge(v1,v1); Assert.assertEquals(expected,actual); } Okay, awesome it works. There is only one crux here, I have proved that the functions work for this case only. However, in my graph theory courses, all I'm doing is proving theorems mathematically (induction, contradiction etc. etc.). So I was wondering is there a way I can prove my unit tests mathematically for correctness? So is there a good practice for this. So we're testing the unit for correctness, instead of testing it for one certain outcome.

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  • Imlpementations of an Interface with Different Types?

    - by b3njamin
    Searched as best I could but unfortunately I've learned nothing relevant; basically I'm trying to work around the following problem in C#... For example, I have three possible references (refA, refB, refC) and I need to load the correct one depending on a configuration option. So far however I can't see a way of doing it that doesn't require me to use the name of said referenced object all through the code (the referenced objects are provided, I can't change them). Hope the following code makes more sense: public ??? LoadedClass; public Init() { /* load the object, according to which version we need... */ if (Config.Version == "refA") { Namespace.refA LoadedClass = new refA(); } else if (Config.Version == "refB") { Namespace.refB LoadedClass = new refB(); } else if (Config.Version == "refC") { Namespace.refC LoadedClass = new refC(); } Run(); } private void Run(){ { LoadedClass.SomeProperty... LoadedClass.SomeMethod(){ etc... } } As you can see, I need the Loaded class to be public, so in my limited way I'm trying to change the type 'dynamically' as I load in which real class I want. Each of refA, refB and refC will implement the same properties and methods but with different names. Again, this is what I'm working with, not by my design. All that said, I tried to get my head around Interfaces (which sound like they're what I'm after) but I'm looking at them and seeing strict types - which makes sense to me, even if it's not useful to me. Any and all ideas and opinions are welcome and I'll clarify anything if necessary. Excuse any silly mistakes I've made in the terminology, I'm learning all this for the first time. I'm really enjoying working with an OOP language so far though - coming from PHP this stuff is blowing my mind :-)

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  • jQuery Syntax Error - Trying to detect viewport size and select background image to use w/CSS

    - by CuppyCakes
    Hi all. Please be gentle, I'm still learning. I imagine that the solution to my problem is simple and that perhaps I have just been in front of the computer too long. I am trying to detect the size of the viewport, and then use a different sized image for a background on an element depending on the size of the viewport. Here is what I have so far: $(document).ready(function(){ var pageWidth = $(window).width(); if ( pageWidth <= 1280 ) { $('#contact').css('background-image', 'url(../images/contact_us_low.jpg)'); } elseif ( pageWidth > 1280 ) { $('#contact').css('background-image', 'url(../images/contact_us_high.jpg)'); } }); Error: missing ; before statement [Break on this error] elseif ( pageWidth 1280 ) {\n (Line 7) To me it seems like all of my semi-colons are in the right place. Two questions: Am I going about solving the problem in a sensible way? To me a simple conditional should solve this background problem, as the code is merely selecting between two images based on what size it detects the viewport to be. Can you please help point out my n00b syntax error? Sometimes it really does help to have an extra pair of eyes look at something like this, even if small. Thank you kindly for your advice, I will continue poking and perusing the docs I have available to me.

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  • jQuery "best practices" is an oxymoron [closed]

    - by n00b
    jQuery "best practices", oxymoron for several reasons sadly To speak candidly, the entire jQuery library has a HIGHLY inconsistent API, and virtually no coding standards. It's basically a subset of JavaScript, a new language if you will, which is probably the most confusing part for normal javascript developers. In my opinion, use normal JavaScript where possible to save on memory consumption. Or, better yet, use a professional tool like YUI. If you already come from a javascript background, you will appreciate it much more than jQuery because it doesn't have n00b wrappers around everything. In tools like YUI, you interact directly with the native DOM to do things, instead of a super-jQuery object that tries to do everything. I'll get voted down for saying the truth. Don't get me wrong, jQuery is cool if you wanna throw something flashy up quick, but if you're going to build a larger app you're going to need a more refined tool (especially since jQuery leaks memory like no other once you start chaining too much things). jQuery does have one of the lowest learning curves, and you won't outgrow it for awhile, but when you do it will be highly apparent and tedious to merge to something else. over 60 years programming experience someone clean this up and community wiki please

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  • opengl + glew in Eclipse (for windows)

    - by echo
    I'm trying to get glew to work under eclipse (mingw) in windows. Seems as if it is extremely unusual not to use Visual Studio in this context. The install instructions for glew is simply "use the project file in build/vc6/"... The glew readme also writes: "If you wish to build GLEW from scratch (update the extension data from the net or add your own extension information), you need a Unix environment (including wget, perl, and GNU make). The extension data is regenerated from the top level source directory with: make extensions" In order to get glew to work in eclipse and windows I have to compile it in a unix environment? Is there no other way? Sure, it would probably be a learning experience to pull that off (if I were to succeed) but I feel that my time is best spent actually working on my project. And even if I did manage to crosscompile everything, would it work in anything but Visual Studio? Is the whole thing unfeasible and the best solution is to install Visual Studio? Google haven't been of much help, I feel like I am the only one that has ever attempted to do this (is there a good reason this?).

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