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  • What is a modern C++ approach to structures containing symbolic constants?

    - by Ken
    enum bool { FALSE = 0, TRUE = 1 }; I'm wondering how to translate this in a modern C++ approach and if there is a well suited container for that; i know that the enum are not really that appreciated, but i can't think about a real alternative in the C++ world. What if would like to associate the execution of a particular method with a state? Ok, this is the part where i will be more verbose. I would like to stress the fact that i'm asking about structures symbolic constants and not about TRUE and FALSE, i'm not that "needy". Suppose that i have a structure that can represent several states with their own constants enum semaphore { GREEN = 0, ORANGE = 1, RED = 2 }; this is C code, now my question is about how to do the same in C++ if there is a better way. My question continue when i ask about the possibility to do something like an automatic triggering when a change of state will occur, for example: int main{ ... semaphore = 1; ... } and without any extra statements this has to trigger a method() just because the semaphore is now orange. I hope that is more clear now.

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  • Region or ItemsSource for large data set in ListBox

    - by Ryan
    I'm having trouble figuring out what the best solution is given the following situation. I'm using Prism 4.1, MEF, and .Net 4.0. I have an object Project that could have a large number (~1000) of Line objects. I'm deciding whether it is better to expose an ObservableCollection<LineViewModel> from my ProjectViewModel and manually create the Line viewmodels there OR set the ListBox as it's own region and activate views that way. I'd still want my LineViewModel to have Prism's shared services (IEventAggregator, etc.) injected, but I don't know how to do that when I manually create the LineViewModel. Any suggestions or thoughts?

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  • Average over a timeframe with missing data

    - by BHare
    Assuming a table such as: UID Name Datetime Users 4 Room 4 2012-08-03 14:00:00 3 2 Room 2 2012-08-03 14:00:00 3 3 Room 3 2012-08-03 14:00:00 1 1 Room 1 2012-08-03 14:00:00 2 3 Room 3 2012-08-03 14:15:00 1 2 Room 2 2012-08-03 14:15:00 4 1 Room 1 2012-08-03 14:15:00 3 1 Room 1 2012-08-03 14:30:00 6 1 Room 1 2012-08-03 14:45:00 3 2 Room 2 2012-08-03 14:45:00 7 3 Room 3 2012-08-03 14:45:00 8 4 Room 4 2012-08-03 14:45:00 4 I wanted to get the average user count of each room (1,2,3,4) from the time 2PM to 3PM. The problem is that sometimes the room may not "check in" at the 15 minute interval time, so the assumption has to be made that the previous last known user count is still valid. For example the check-in's for 2012-08-03 14:15:00 room 4 never checked in, so it must be assumed that room 4 had 3 users at 2012-08-03 14:15:00 because that is what it had at 2012-08-03 14:00:00 This follows on through so that the average user count I am looking for is as follows: Room 1: (2 + 3 + 6 + 3) / 4 = 3.5 Room 2: (3 + 4 + 4 + 7) / 4 = 4.5 Room 3: (1 + 1 + 1 + 8) / 4 = 2.75 Room 4: (3 + 3 + 3 + 4) / 4 = 3.25 where # is the assumed number based on the previous known check-in. I am wondering if it's possible to so this with SQL alone? if not I am curious of a ingenious PHP solution that isn't just bruteforce math, as such as my quick inaccurate pseudo code: foreach ($rooms_id_array as $room_id) { $SQL = "SELECT * FROM `table` WHERE (`UID` == $room_id && `Datetime` >= 2012-08-03 14:00:00 && `Datetime` <= 2012-08-03 15:00:00)"; $result = query($SQL); if ( count($result) < 4 ) { // go through each date and find what is missing, and then go to previous date and use that instead } else { foreach ($result) $sum += $result; $avg = $sum / 4; } }

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  • persist values/variables from page to page

    - by Todd
    Hello, I'm wondering if there's another solution to my problem, that's considered more the Sharepoint way. FIrstly, my site is an Internet site, not Intranet. The problem is, all I'm trying to do is save values/variables from page to page in Sharepoint. I know the issue with Session Variables, but this seems to be the only way I can see to accomplish this. I know there are webparts that can store this value, but am I wrong in thinking this won't be persisted from page to page? Basically, I'll be extending the Content Query Web Part to dynamically filter it's results based off of a variable/value. The user chooses their 'area' from a dropdown, and the CQWP in the site will change and query results based off of this value (It will be a provincial structure as it is a Canadian site, so if someone chooses the province 'Ontario', this value is saved in a global variable, and these extended CQWP that are throughout the site, will get this value, and query lists flagged as Ontario). Is Session variables the only solution? Thanks everyone!

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  • I have data about deadlocks, but I can't understand why they occur

    - by Alex
    I am receiving a lot of deadlocks in my big web application. http://stackoverflow.com/questions/2941233/how-to-automatically-re-run-deadlocked-transaction-asp-net-mvc-sql-server Here I wanted to re-run deadlocked transactions, but I was told to get rid of the deadlocks - it's much better, than trying to catch the deadlocks. So I spent the whole day with SQL Profiler, setting the tracing keys etc. And this is what I got. There's a Users table. I have a very high usable page with the following query (it's not the only query, but it's the one that causes troubles) UPDATE Users SET views = views + 1 WHERE ID IN (SELECT AuthorID FROM Articles WHERE ArticleID = @ArticleID) And then there's the following query in ALL pages: User = DB.Users.SingleOrDefault(u => u.Password == password && u.Name == username); That's where I get User from cookies. Very often a deadlock occurs and this second Linq-to-SQL query is chosen as a victim, so it's not run, and users of my site see an error screen. I read a lot about deadlocks... And I don't understand why this is causing a deadlock. So obviously both of this queries run very often. At least once a second. Maybe even more often (300-400 users online). So they can be run at the same time very easily, but why does it cause a deadlock? Please help. Thank you

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  • List<T> paging asp.net

    - by user1397978
    Using a three-tier architecture, I have a list of objects List<object> careerList = new List<object>(); ModuleDTO module = new ModuleDTO(); careerList = module.getDegreeCodeByQualification(qualificationCode); which I then add to a gridview like so: gridViewMaster.DataSource = careerList; gridViewMaster.DataBind(); What I'd like to do is then enable paging on the gridview. My gridview so far is: <asp:GridView ID="gridViewMaster" runat="server" AutoGenerateColumns="False" GridLines="None" BorderWidth="1px" CellPadding="2" DataKeyNames="Grouping" ForeColor="Black" onrowdatabound="gridViewMaster_RowDataBound" CssClass="mGrid" PagerStyle-CssClass="pgr" AlternatingRowStyle-CssClass="alt" OnPageIndexChanging="gridView_PageIndexChanging" AllowPaging="True" > Is it possible to do enable paging on a list's without having to change that list to a Datatable or Dataview? If there is a way, this would help a lot. So far my events are as follows: protected void gridView_PageIndexChanging(object sender, GridViewPageEventArgs e) { gridViewMaster.PageIndex = e.NewPageIndex; List<object> careerList = new List<object>(); ModuleDTO module = new ModuleDTO(); careerList = module.getDegreeCodeByQualification(qualificationCode); ModalProgress.Show(); System.Threading.Thread.Sleep(1000); JobPanel.Visible = true; gridViewMaster.DataSource = careerList.Distinct(); gridViewMaster.DataBind(); } Someone PLEASE HELP ME!!! Thank you

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  • ASP.NET - Update progress while processing data

    - by Danny
    Hope I can explain this correctly. I have a process, that outputs step by step messages (i.e., Processing item 1... Error in item 2 etc etc). I want this to be outputted to the user during the process, and not at the end. I pretty sure i need to do this with threading, but can't find a decent example. Thanks in advanced.

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  • Rowwise iteration of a dictionay object

    - by mono
    I have a dictionary object like: Dictionary<string, HashSet<int>> dict = new Dictionary<string, HashSet<int>>(); dict.Add("foo", new HashSet<int>() { 15,12,16,18}); dict.Add("boo", new HashSet<int>() { 16,47,45,21 }); I have to print in such a way such that result would be as following at each iteration: It1: foo boo //only the key in a row It2: 15 16 It3: 16 47 Can anyone help me to achieve this. Thanks.

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  • Binary Search Tree can't delete the root

    - by Ali Zahr
    Everything is working fine in this function, but the problem is that I can't delete the root, I couldn't figure out what's the bug here.I've traced the "else part" it works fine until the return, it returns the old value I don't know why. Plz Help! node *removeNode(node *Root, int key) { node *tmp = new node; if(key > Root->value) Root->right = removeNode(Root->right,key); else if(key < Root->value) Root->left = removeNode(Root->left, key); else if(Root->left != NULL && Root->right != NULL) { node *minNode = findNode(Root->right); Root->value = minNode->value; Root->right = removeNode(Root->right,Root->value); } else { tmp = Root; if(Root->left == NULL) Root = Root->right; else if(Root->right == NULL) Root = Root->left; delete tmp; } return Root; }

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  • Screen orientation change forces data re-entry

    - by Timbermar
    I'm developing a simple app, only a handful of activities and nothing to complicated. The issue I'm having is that in a few of my activities I have EditText widgets, and when the screen is rotated, these widgets loose their values. They still visually, that is, on the handset screen, report their values from before the rotation, but to the code report their default values. An example, I have an activity with an EditText, I enter a number, 15, the calculator starts calculating, displays a result. If at this point I rotate to a different orientation, as expected the activity dies, reloads, shows the new orientation, my value of 15 is still in the EditText, however the calculator (the code) calculates as if it was 0, which is the initial value. I have not tried changing the initial value to see if it is really pulling from the default value, or just setting itself to 0 when I cast it as an int. If I didn't explain this well enough, let me know, I can add source code if I need to. Thanks.

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  • data filter using dataloadoptions

    - by Tassadaque
    Using dataloadoptions i have tried the following example Northwnd db = new Northwnd(@"northwnd.mdf"); // Preload Orders for Customer. // One directive per relationship to be preloaded. DataLoadOptions ds = new DataLoadOptions(); ds.LoadWith<Customer>(c => c.Orders); ds.AssociateWith<Customer> (c => c.Orders.Where(p => p.ShippedDate != DateTime.Today)); db.LoadOptions = ds; var custQuery = from cust in db.Customers where cust.City == "London" select cust; foreach (Customer custObj in custQuery) { Console.WriteLine("Customer ID: {0}", custObj.CustomerID); foreach (Order ord in custObj.Orders) { Console.WriteLine("\tOrder ID: {0}", ord.OrderID); foreach (OrderDetail detail in ord.OrderDetails) { Console.WriteLine("\t\tProduct ID: {0}", detail.ProductID); } } } Now i need to ask how can i display Category ID and Category Name of the productID (i am supposing that One product can be in at most one category) by extending the above example Regards

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  • The C vs. C++ way

    - by amc
    Hi, So I have to write a program that will iterate through an image and record the pixel locations corresponding to each color pixel that appears in it. For example, given http://www.socuteurl.com/fishywishykissy I need to find the coordinates of all yellow, purple, dark pink, etc pixels. In C++ I would use a hash table to do this. I would iterate through the image, check each pixel's value, look up that value and either add to a vector of pixel coordinates if it were found or add a new entry to the table if the value were not already there. The problem is that I may need to write this program in pure C instead of C++. How would I go about doing this in C? I feel like implementing a hash table would be pretty obnoxious and error-prone: should I avoid doing that? I'm pretty inexperienced with C and have a fair amount of C++ experience, if that matters. Thanks.

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  • What's the point of having to provide a cacheName for NSFetchedResultsController?

    - by dontWatchMyProfile
    NSFetchedResultsController *frc = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:moc sectionNameKeyPath:nil cacheName:@"Root"]; Why do we have to think about a cacheName? How important is this decision? What would happen if there are two NSFetchedResultsController instances using the exact same cacheName? Does that matter? Is that some kind of singleton stuff? Thinking about Core Animation, there's also this strange animationID parameter, but setting it to the exact same thing for dozens of simultaneous animations doesn't hurt the animations at all. So I guess it's probably the same thing here...or not?

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  • Silverlight Image Data Binding

    - by Alexander
    I am new to Silverlight, and have an issue with binding. I have a class ItemsManager, that has inside its scope another class Item. class ItemsManager { ... class Item : INotifyPropertyChanged { ... private BitmapImage bitmapSource; public BitmapImage BitmapSource { get { return bitmapSource; } set { bitmapSource = value; if(PropertyChanged != null )PropertyChanged("BitmapSource") } } } } I do the following in code to test binding: { ItemsManager.Instance.AddItem("123"); //Items manager started downloading item visual //part (in my case bitmap image png) Binding b = new Binding("Source"); b.Source = ItemsManager.Instance.GetItem("123").BitmapSource; b.BindsDirectlyToSource = true; Image img = new Image(); img.SetBinding(Image.SourceProperty, b); img.Width = (double)100.0; img.Height = (double)100.0; LayoutRoot.Children.Add(img); } Once image is loaded, image doesn't appear. Though, if I set directly after image has been loaded its source, it displays well. I also noticed that PropertyChanged("BitmapSource") never fires, because PropertyChanged is null, like Image never binded to it. I am looking forward to hearing from you!

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  • iPhone app store approval - coredata design change

    - by satyam
    I created an app, uploaded to app store and approved by app store as well. Its ready for download. The app is based on coredata. Now I changed the design of the app to add new functionality. Changes include addition of new attributes to current entities, deletion of few entities etc. Now, if I upload the app to app store, does it approve or not? Do I have to put and Note saying that "Please uninstall old version and install new version?" Will my app be approved first of all or not.

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  • how to select and group mysql data based on the follwoing table

    - by user1151680
    how can I achieve the desired result in mysql if my table looks like this. result|year 1 |2011 2 |2011 1 |2011 0 |2011 1 |2012 2 |2012 1 = Won, 2 = lost, 0 = draw Every year can have multiple values like this. Not sure how I can get the desired result like below. year won lost draw totalPlayed 2011 2 1 1 3 2012 1 1 0 2 I have tried the following query but does not get the desired result select year, league_types.league_name, sum(if(result = 1,1,0)) as won, sum(if(result = 0,1,0)) as draw, sum(if(result = 4,1,0)) as noResult, sum(if(result = 2,1,0)) as lost, sum(if(result = 3,1,0)) as tied, sum(if(result > 0 and result < 4,1,0)) as played from match_score_card inner join fixtures on match_score_card.match_id = fixtures.match_id inner join league_types on fixtures.league_id = league_types.league_id where team_id = 1 group by year order by year desc

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  • Identifying the parts of this typedef struct in C?

    - by Tommy
    Please help me identify the parts of this typdef struct and what each part does and how it can be used: typedef struct my_struct { int a; int b; int c; } struct_int, *p_s; struct_int struct_array[5]; my_struct is the...? struct_int is the...? *p_s is the...and can be used to point to what? struct_array is the...? Also, when creating the array of structs, why do we use struct_int instead of my_struct ? Thank You!

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