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  • math.Random isn't working right

    - by RandomlyKnighted
    I'm trying to simulate a coin flip using the code below. public class Coin { public static double result; int[] count = new count[2]; public static void flip() { result = Math.random(); } public static boolean isHeads() { if (result == 0.0) { count[0]++; return false; } else { count[1]++; return true; } } public static void main(String[] args) { flip(); isHeads(); System.out.println(count[0]); System.out.println(count[1]); } } For some reason Eclipse says that the import java.util.Random; is never used even though I'm clearly using it. I didn't put my for loop into the code above but it loops n number of times and then outputs the result. No matter how many times it loops it always returns that the result is greater than 0.0 which can't be right. Am I calling Math.random incorrectly?

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  • Is Using Tuples in my .NET 4.0 Code a Poor Design Decision?

    - by Jason Webb
    With the addition of the Tuple class in .net 4, I have been trying to decide if using them in my design is a bad choice or not. The way I see it, a Tuple can be a shortcut to writing a result class (I am sure there are other uses too). So this: public class ResultType { public string StringValue { get; set; } public int IntValue { get; set; } } public ResultType GetAClassedValue() { //..Do Some Stuff ResultType result = new ResultType { StringValue = "A String", IntValue = 2 }; return result; } Is equivalent to this: public Tuple<string, int> GetATupledValue() { //...Do Some stuff Tuple<string, int> result = new Tuple<string, int>("A String", 2); return result; } So setting aside the possibility that I am missing the point of Tuples, is the example with a Tuple a bad design choice? To me it seems like less clutter, but not as self documenting and clean. Meaning that with the type ResultType, it is very clear later on what each part of the class means but you have extra code to maintain. With the Tuple<string, int> you will need to look up and figure out what each Item represents, but you write and maintain less code. Any experience you have had with this choice would be greatly appreciated.

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  • What are the benefits of a classical structure over a prototyple one?

    - by Rixius
    I have only recently started programming significantly, and being completely self-taught, I unfortunately don't have the benefits of a detailed Computer science course. I've been reading a lot about JavaScript lately, and I'm trying to find the benefit in classes over the prototype nature of JavaScript. The question seems to be drawn down the middle of which one is better, and I want to see the classical side of it. When I look at the prototype example: var inst_a = { "X": 123, "Y": 321, add: function () { return this.X+this.Y; } }; document.write(inst_a.add()); And then the classical version function A(x,y){ this.X = x; this.Y = y; this.add = function(){ return this.X+this.Y; }; }; var inst_a = new A(123,321); document.write(inst_a.add()); I begun thinking about this because I'm looking at the new ecmascript revision 5 and a lot of people seem up in arms that they didn't add a Class system.

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  • C#: How to implement a smart cache

    - by Svish
    I have some places where implementing some sort of cache might be useful. For example in cases of doing resource lookups based on custom strings, finding names of properties using reflection, or to have only one PropertyChangedEventArgs per property name. A simple example of the last one: public static class Cache { private static Dictionary<string, PropertyChangedEventArgs> cache; static Cache() { cache = new Dictionary<string, PropertyChangedEventArgs>(); } public static PropertyChangedEventArgs GetPropertyChangedEventArgsa(string propertyName) { if (cache.ContainsKey(propertyName)) return cache[propertyName]; return cache[propertyName] = new PropertyChangedEventArgs(propertyName); } } But, will this work well? For example if we had a whole load of different propertyNames, that would mean we would end up with a huge cache sitting there never being garbage collected or anything. I'm imagining if what is cached are larger values and if the application is a long-running one, this might end up as kind of a problem... or what do you think? How should a good cache be implemented? Is this one good enough for most purposes? Any examples of some nice cache implementations that are not too hard to understand or way too complex to implement?

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  • How do I display core data on second view controller?

    - by jon
    I am working on my first core data iPhone application. I am using a navigation controller, and the root view controller displays 4 rows. Clicking the first row takes me to a second table view controller. However, when I click the back button, repeat the row tap, click the back button again, and tap the row a third time, I get an error. I have been researching this for a week with no success. I can reproduce the error easily: Create a new Navigation-based Application, use Core Data for storage, call it MyTest which creates MyTestAppDelegate and RootViewController. Add new UIViewController subclass, with UITableViewController and xib, call it ListViewController. Copy code from RootViewController.h and .m to ListViewController.h and .m., changing the file names appropriately. To simplify the code, I removed the trailing “_” from all variables. In RootViewController, I added #import ListViewController.h, set up an array to display 4 rows and navigate to ListViewController when clicking the first row. In ListViewController.m, I added #import MyTestAppDelegate.h” and the following code: - (void)viewDidLoad { [super viewDidLoad]; if (managedObjectContext == nil) { managedObjectContext = [(MyTestAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; } .. } The sequence that causes the error is tap row, return, tap row, return, tap row - error. managedObjectContext is synthesized for the third time. I appreciate your patience and your help, as this makes no sense to me. ADDENDUM: I may have a partial solution. http://www.iphonedevsdk.com/forum/iphone-sdk-development/41688-accessing-app-delegates-managed-object-context.html If I do not release the managedObjectContext in the .m file, the error goes away. Is that ok or will that cause me issues? - (void)dealloc { [fetchedResultsController release]; // [managedObjectContext release]; [super dealloc]; } ADDENDUM 2: See solution below. Sorry for the formatting issues - this was my first post.

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  • Make a router like zend

    - by Vahan
    I have a url http://*.com/branch/module/view/id/1/cat/2/etc/3. It becomes. array ( 'module'=>'branch', 'controller'=>'module', 'action'=>'view' ); next I need to get the params. Ihave this array. /*function getNextSegments($n,$segments) { return array_slice ( $q = $this->segments, $n + 1 ); } $params = getNextSegments(3); */ array ( 0 => 'id', 1 => '1', 2 => 'cat', 3 => '2', 4 => 'etc', 5 => '3' );//params And i wanna convert it to this one: array ( 'id'=1, 'cat'=2, 'etc'=3, ); How i can do this using php function. I know I can do using for or foreach, but I think php has such function , but i cant find it :(. Thank you. class A { protected function combine($params) { $count = count ( $params ); $returnArray = array (); for($i = 0; $i < $count; $i += 2) { $g = $i % 2; if ($g == 0 or $g > 0) { if (isset ( $params [$i] ) and isset ( $params [$i + 1] )) $returnArray [$params [$i]] = $params [$i + 1]; } } return $returnArray; } } This works normaly. If anybody has better login for this please help. Thank you again.

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  • codeigniter and JSON

    - by ole
    Hello all i having a problem that it only get 1 value in my database and its my title and i want to show content and username from the same table to. here is my JSON kode <script type="text/javascript"> $.getJSON( 'ajax/forumThreads', function(data) { alert(data[0].overskrift); alert(data[0].indhold); } ); </script> my controller <?php class ajax extends Controller { function forumThreads() { $this->load->model('ajax_model'); $data['forum_list'] = $this->ajax_model->forumList(); if ($data['forum_list'] !== false) { echo json_encode($data['forum_list']); } } } my model fle <?php class ajax_model extends Model { function forumList() { $this->db->select('overskrift', 'indhold', 'brugernavn', 'dato'); $this->db->order_by('id', 'desc'); $this->db->limit(5); $forum_list = $this->db->get('forum_traad'); if($forum_list->num_rows() > 0) { return $forum_list->result_array(); } else { return false; } } }

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  • Passing list of items from Controller/Model to a variable in javascript - autocomplete

    - by newbie_developer
    I've a method in a NamesModel which fetches all the names and returns a list of names: public static List<NamesModel> GetAllNames() { List<NamesModel> names = new List<NamesModel>(); // // code to fetch records // return names; } In my controller: public ActionResult Index() { NamesModel model = new NamesModel(); model.GetAllNames(); return View(model); } In the view, I've got a textbox: @Html.TextBox("search-name") Now in my javascript, I want to fetch all names into a variable either from a model (from method) or from controller, for example: <script type="text/javascript"> $(function () { var names = ........... $(document).ready(function () { $('#search-name').autocomplete({ source: names }); }); }); </script> If I use hardcoding then it works but I want to use the names stored in the db. Is it possible? hardcoding example: var names = ["abc", "xyz"];

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  • Exposing a C++ API to C#

    - by Siyfion
    So what I have is a C++ API contained within a *.dll and I want to use a C# application to call methods within the API. So far I have created a C++ / CLR project that includes the native C++ API and managed to create a "bridge" class that looks a bit like the following: ManagedBridge.h namespace ManagedAPIWrapper { public ref class Bridge { public: int bridge_test(void); int bridge_test2(api_struct* temp); } } ManagedBridge.cpp int Bridge::bridge_test(void) { return test(); } int Bridge::bridge_test2(api_struct* temp) { return test2(temp); } I also have a C# application that has a reference to the C++/CLR "Bridge.dll" and then uses the methods contained within. I have a number of problems with this: I can't figure out how to call bridge_test2 within the C# program, as it has no knowledge of what a api_struct actually is. I know that I need to marshal the object somewhere, but do I do it in the C# program or the C++/CLR bridge? This seems like a very long-winded way of exposing all of the methods in the API, is there not an easier way that I'm missing out? (That doesn't use P/Invoke!)

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  • No result when Rally.data.WsapiDataStore lacks permissions

    - by user1195996
    I'm calling Ext.create('Rally.data.WsapiDataStore', params), and looking for results with the load event. I'm requesting a number of objects across programs that the user may or may not have read permission for. This works fine for queries where the user has permissions. But in the case where the user does not have permission and presumably gets zero results back, the load event does not seem to fire at all. I would expect it to fire with the unsuccessful flag or else to return with empty results. Since I don't know that the request has failed, my program waits and waits. How can I tell if a this request fails to return because of security? BTW, looking at the network stats, I believe all my requests get a "200 OK" status back. Here is the method I use to create the various data stores: _createDataStore: function(params) { this.openRequests++; var createParams = { model: params.type, autoLoad: true, // So I can later determine which query type it is, and which program requestType: params.requestType == undefined ? params.type : params.requestType, program: this.program, listeners: { load: this._onDataLoaded, scope: this }, filters: params.filters, pageSize: params.pageSize, fetch: params.fetch, context: { project: this.project, projectScopeUp: false, projectScopeDown: true }, pageSize: 1 // We only need the count }; console.log('_createDataStore', this.program, createParams.requestType); Ext.create('Rally.data.WsapiDataStore', createParams); }, And here is the _onDataLoaded method: _onDataLoaded: function(store, data, successB) { console.log('_onDataLoaded', this.program, successB); ... I only see this function called for those queries for which the account has permissions.

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  • Operator+ for a subtype of a template class.

    - by baol
    I have a template class that defines a subtype. I'm trying to define the binary operator+ as a template function, but the compiler cannot resolve the template version of the operator+. #include <iostream> template<typename other_type> struct c { c(other_type v) : cs(v) {} struct subtype { subtype(other_type v) : val(v) {} other_type val; } cs; }; template<typename other_type> typename c<other_type>::subtype operator+(const typename c<other_type>::subtype& left, const typename c<other_type>::subtype& right) { return typename c<other_type>::subtype(left.val + right.val); } // This one works // c<int>::subtype operator+(const c<int>::subtype& left, // const c<int>::subtype& right) // { return c<int>::subtype(left.val + right.val); } int main() { c<int> c1 = 1; c<int> c2 = 2; c<int>::subtype cs3 = c1.cs + c2.cs; std::cerr << cs3.val << std::endl; } I think the reason is because the compiler (g++4.3) cannot guess the template type so it's searching for operator+<int> instead of operator+. What's the reason for that? What elegant solution can you suggest?

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  • C++ STL 101: Overload function causes build error

    - by Sidjal
    Trivial code that works if I do not overload myfunc. void myfunc(int i) { std::cout << "calling myfunc with arg " << i << std::endl; } void myfunc(std::string s) { std::cout << "calling myfunc with arg " << s << std::endl; } void testalgos() { std::vector<int> v; v.push_back(1); v.push_back(2); std::vector<std::string> s; s.push_back("one"); s.push_back("two"); std::for_each( v.begin(), v.end(), myfunc); std::for_each( s.begin(), s.end(), myfunc); return; } int _tmain(int argc, _TCHAR* argv[]) { std::cout << "Hello World" << std::endl; testalgos(); return 0; } The following build errors repeat for both for_each calls. error C2914: 'std::for_each' : cannot deduce template argument as function argument is ambiguous error C2784: '_Fn1 std::for_each(_InIt,_InIt,_Fn1)' : could not deduce template argument for '_InIt' from 'std::_Vector_iterator<_Ty,_Alloc'. It does work if I do not overload myfunc.Can someone explain what is happening here. TIA

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  • multiplying all elements in an array by an outside number?

    - by prodo
    I need to multiple all the values in an array by 3000 which in turn would create a new array that I will use to subtract from another array. I've tried to create a separate method that would do that for me but all I got back in the multiplied array was a bunch of numbers and symbols strangely? here is the code that I wrote public static void main(String[] args) { int numberOfTaxpayers = Integer.parseInt(JOptionPane.showInputDialog("Enter how many users you would like to calculate taxes for: "); int[] usernumChild = new int[numberOfTaxPayers]; for (int i = 0; i < usernumChild.length; i++) { usernumChild[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter number of children for user "+ (i+1) +": ")); }//this for loop finds out the number of children per user so we can later multiply each input by 3000 to create an array that determine dependency exemption for each user int[] depndExemp = multiply(usernumChild, 3000);//this was the calling of the multiply method... somewhere here is the error!! }//end main method public static int[] multiply(int[] children, int number) { int array[] = new int[children.length]; for( int i = 0; i < children.length; i++) { children[i] = children[i] * number; }//end for return array; }//this is the method that I was shown in a previous post on how to create return an array in this the dependency exemption array but when I tested this by printing out the dependency array all I received were a jumble of wrong numbers.

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  • C# property exactly the same, defined in two places

    - by Sarah Vessels
    I have the following classes: Defect - represents a type of data that can be found in a database FilterQuery - provides a way of querying the database by setting simple Boolean filters Both Defect and FilterQuery implement the same interface: IDefectProperties. This interface specifies particular fields that are in the database. Different classes have methods that return lists of Defect instances. With FilterQuery, you specify some filters for the particular properties implemented as part of IDefectProperties, and then you run the query and get back a list of Defect instances. My problem is that I end up implementing some properties exactly the same in FilterQuery and Defect. The two are inherently different classes, they just share some of the same properties. For example: public DateTime SubmitDateAsDate { get { return DateTime.Parse(SubmitDate); } set { SubmitDate = value.ToString(); } } This is a property required by IDefectProperties that depends on a different property, SubmitDate, which returns a string instead of a DateTime. Now SubmitDate is implemented differently in Defect and FilterQuery, but SubmitDateAsDate is exactly the same. Is there a way that I can define SubmitDateAsDate in only place, but both Defect and FilterQuery provide it as a property? FilterQuery and Defect already inherit from two different classes, and it wouldn't make sense for them to share an ancestor anyway, I think. I am open to suggestions as to my design here as well.

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  • Memcached getDelayed alternative implementation

    - by iBobo
    I would like to use getDelayed on the PHP Memcached extension but I think it's not implemented in the right way. Right now you ask for some keys and then retrieve all of them with fetch() and fetchAll(). But imagine a scenario where I need to retrieve 15 keys used in different parts of the page which I don't know in advance, but I can ask the various objects to give me the list. What I want is give the Memcached instance this list (each component would give its part) then later when I need them retrieve from the instance, but not all of them at once: each component would take the one it needs. Basically if I were to implement this I would prohibit using getDelayed alone and implement a bookGet($keys) method where you would add the keys to book (which actually calls getDelayed), and redefine get to handle these three cases: key is booked and retrieved - return the value; key is booked but not retrieved - go and force the fetch of the booked keys and return the correct value; key not booked - do a normal lookup. I want to know if this makes sense, your thoughts on the subject and if someone already implemented this or maybe PECL Memcached already works this way and actually the documentation doesn't explain it correctly.

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  • Is `super` local variable?

    - by Michael
    // A : Parent @implementation A -(id) init { // change self here then return it } @end A A *a = [[A alloc] init]; a. Just wondering, if self is a local variable or global? If it's local then what is the point of self = [super init] in init? I can successfully define some local variable and use like this, why would I need to assign it to self. -(id) init { id tmp = [super init]; if(tmp != nil) { //do stuff } return tmp; } b. If [super init] returns some other object instance and I have to overwrite self then I will not be able to access A's methods any more, since it will be completely new object? Am I right? c. super and self pointing to the same memory and the major difference between them is method lookup order. Am I right? sorry, don't have Mac to try, learning theory as for now...

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  • Java: I've created a list of word objects to include the name and the frequency, but having trouble

    - by adam08
    Hi Everyone, I'm working on a project which has a dictionary of words and I'm extracting them and adding them to an ArrayList as word objects. I have a class called Word as below. What I'm wondering is how do I access these word objects to update the frequency? As part of this project, I need to only have one unique word, and increase the frequency of that word by the number of occurrences in the dictionary. Word(String word) { this.word = word; this.freq = 0; } public String getWord() { return word; } public int getFreq() { return freq; } public void setFreq() { freq = freq + 1; } This is how I am adding the word objects to the ArrayList...I think it's ok? String pattern = "[^a-zA-Z\\s]"; String strippedString = line.replaceAll(pattern, ""); line = strippedString.toLowerCase(); StringTokenizer st = new StringTokenizer(line); while (st.hasMoreTokens()) { String newWord = st.nextToken(); word.add(new Word(newWord)); count++; }

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  • Bizarre static_cast trick?

    - by Rob
    While perusing the Qt source code I came across this gem: template <class T> inline T qgraphicsitem_cast(const QGraphicsItem *item) { return int(static_cast<T>(0)->Type) == int(QGraphicsItem::Type) || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0; } Notice the static_cast<T>(0)->Type? I've been using C++ for many years but have never seen 0 being used in a static_cast before. What is this code doing and is it safe? Background: If you derive from QGraphicsItem you are meant to declare an unique enum value called Type that and implement a virtual function called type that returns it, e.g.: class Item : public QGraphicsItem { public: enum { Type = MAGIC_NUMBER }; int type() const { return Type; } ... }; You can then do this: QGraphicsItem* item = new Item; ... Item* derivedItem = qgraphicsitem_cast<Item*>(item); This will probably help explain what that static_cast is trying to do.

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  • $this.attr() stops Jquery dialog from opening

    - by user342391
    I am using the following code to post my form data to player/index.php and open it in a dialog. Because I have multiple of these forms in my table I need to use $(this). But now it doesn't open in a dialog. New code (doesn't open dialog but display data in url): $("#recordingdialog").dialog({ //other options, width, height, etc... modal: true, bgiframe: true, autoOpen: false, height: 200, width: 350, draggable: true, resizeable: true, title: "Play Recording",}); $(this).click(function() { $.post('player/index.php', $(this).attr('form').serialize(), function (data) { $("#recordingdialog").html(data).dialog("open"); }); return false; }); Old code (only works on one form): $("#recordingdialog").dialog({ //other options, width, height, etc... modal: true, bgiframe: true, autoOpen: false, height: 550, width: 550, draggable: true, resizeable: true, title: "Play Recording",}); $("#wavajax button").click(function() { $.post('player/index.php', $("#wavajax").serialize(), function (data) { $("#recordingdialog").html(data).dialog("open"); }); return false; });

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  • How costly performance-wise are these actions in iPhone objective-C?

    - by Alex Gosselin
    This is really a few questions in one, I'm wondering what the performance cost is for these things, as I haven't really been following a best practice of any sort for these. The answers may also be useful to other readers, if somebody knows these. (1) If I need the core data managed object context, is it bad to use #import "myAppDelegate.h" //farther down in the code: NSManagedObjectContext *context = [(myAppDelegate.h*)[[UIApplication sharedApplication] delegate] managedObjectContext]; as opposed to leaving the warning you get if you don't cast the delegate? (2) What is the cheapest way to hard-code a string? I have been using return @"myString"; on occasion in some functions where I need to pass it to a variety of places, is it better to do it this way: static NSString *str = @"myString"; return str; (3) How costly is it to subclass an object i wrote vs. making a new one, in general? (4) When I am using core data and navigating through a hierarchy of some sort, is it necessary to turn things back into faults somehow after I read some info from them? or is this done automatically? Thanks for any help.

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  • PHP class extends not working why and is this how to correctly extend a class?

    - by Matthew
    Hi so I'm trying to understand how inherteince works in PHP using object oriented programming. The main class is Computer, the class that is inheriting is Mouse. I'm extedning the Computer class with the mouse class. I use __construct in each class, when I istinate the class I use the pc type first and if it has mouse after. For some reason computer returns null? why is this? class Computer { protected $type = 'null'; public function __construct($type) { $this->type = $type; } public function computertype() { $this->type = strtoupper($this->type); return $this->type; } } class Mouse extends Computer { protected $hasmouse = 'null'; public function __construct($hasmouse){ $this->hasmouse = $hasmouse; } public function computermouse() { if($this->hasmouse == 'Y') { return 'This Computer has a mouse'; } } } $pc = new Computer('PC', 'Y'); echo $pc->computertype; echo $pc->computermouse;

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  • Python - creating a list with 2 characteristics bug

    - by user2733911
    The goal is to create a list of 99 elements. All elements must be 1s or 0s. The first element must be a 1. There must be 7 1s in total. import random import math import time # constants determined through testing generation_constant = 0.96 def generate_candidate(): coin_vector = [] coin_vector.append(1) for i in range(0, 99): random_value = random.random() if (random_value > generation_constant): coin_vector.append(1) else: coin_vector.append(0) return coin_vector def validate_candidate(vector): vector_sum = sum(vector) sum_test = False if (vector_sum == 7): sum_test = True first_slot = vector[0] first_test = False if (first_slot == 1): first_test = True return (sum_test and first_test) vector1 = generate_candidate() while (validate_candidate(vector1) == False): vector1 = generate_candidate() print vector1, sum(vector1), validate_candidate(vector1) Most of the time, the output is correct, saying something like [1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0] 7 True but sometimes, the output is: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] 2 False What exactly am I doing wrong?

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  • .NET List Thread-Safe Implementation Suggestion needed

    - by Bamboo
    .Net List class isn't thread safe. I hope to achieve the minimal lock needed and yet still fulfilling the requirement such that as for reading, phantom record is allowed, and for writing, they must be thread-safe so there won't be any lost updates. So I have something like public static List<string> list = new List<string>(); In Methods that have **List.Add**/**List.Remove** , I always lock to assure thread safety lock (lockHelper) { list.Add(obj); or list.Remove(obj); } In Methods that requires **List Reading** I don't care about phantom record so I go ahead to read without any locking. In this case. Return a bool by checking whether a string had been added. if (list.Count() != 0) { return list.Contains("some string") } All I did was locking write accesses, and allow read accesses to go through without any locking. Is my thread safety idea valid? I understand there is List size expansion. Will it be ok? My guess is that when a List is expanding, it may uses a temp. list. This is ok becasue the temp list size will always have a boundary, and .Net class is well implemented, ie. there shouldn't be any indexOutOfBound or circular reference problems when reading was caught in updates.

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  • MVC 3 beta + Dependency Resolver + Unity = got problem

    - by drsim
    Hi everyone. I'm tried to use Dependency Resolver with Unity, and got some problem when my Controller creating. Here example of controller: public class AccountController : Controller { private readonly ICourseService _courseService; public AccountController(ICourseService courseService) { _courseService = courseService; } } But, when Controller try to create - i got an exception "No parameterless constructor defined for this object." I even try to add default constructor for this controller, but courseService didn't create. Also try to add property with [Dependency] attribute - nothing happened. Here is Dependency Resolver class: public class UnityDependencyResolver : IDependencyResolver { private readonly IUnityContainer _container; public UnityDependencyResolver(IUnityContainer container) { _container = container; } public object GetService(Type serviceType) { return _container.IsRegistered(serviceType) ? _container.Resolve(serviceType) : null; } public IEnumerable<object> GetServices(Type serviceType) { return _container.IsRegistered(serviceType) ? _container.ResolveAll(serviceType) : new List<object>(); } } and Global.asax.cs: protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); var container = new UnityContainer(); container.RegisterType<ICourseService, CourseService>(); DependencyResolver.SetResolver(new UnityDependencyResolver(container)); } Can anyone help me ?

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  • MySQL - Exclude rows from Select based on duplication of two columns

    - by Carson C.
    I am attempting to narrow results of an existing complex query based on conditional matches on multiple columns within the returned data set. I'll attempt to simplify the data as much as possible here. Assume that the following table structure represents the data that my existing complex query has already selected (here ordered by date): +----+-----------+------+------------+ | id | remote_id | type | date | +----+-----------+------+------------+ | 1 | 1 | A | 2011-01-01 | | 3 | 1 | A | 2011-01-07 | | 5 | 1 | B | 2011-01-07 | | 4 | 1 | A | 2011-05-01 | +----+-----------+------+------------+ I need to select from that data set based on the following criteria: If the pairing of remote_id and type is unique to the set, return the row always If the pairing of remote_id and type is not unique to the set, take the following action: Of the sets of rows for which the pairing of remote_id and type are not unique, return only the single row for which date is greatest and still less than or equal to now. So, if today is 2010-01-10, I'd like the data set returned to be: +----+-----------+------+------------+ | id | remote_id | type | date | +----+-----------+------+------------+ | 3 | 1 | A | 2011-01-07 | | 5 | 1 | B | 2011-01-07 | +----+-----------+------+------------+ For some reason I'm having no luck wrapping my head around this one. I suspect the answer lies in good application of group_by, but I just can't grasp it. Any help is greatly appreciated!

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