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  • Problem with SqlLite database in Qt SDK 1.0.2

    - by Risino
    Hi I have a problem with SqlLite database. Here is my code: void incomeDialog::on_add_pushButton_clicked() { int a = ui->income_lineEdit->text().toInt(); int b = ui->other_lineEdit->text().toInt(); int c = (a+b); db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("money.db"); QSqlQuery query(db); query.exec("create table Income" "(Month TEXT, Payment NUMBER, Other NUMBER, Together NUMBER)"); query.prepare("INSERT INTO Income values (?,?,?,?)"); query.addBindValue(ui->comboBox->currentText()); query.addBindValue(ui->income_lineEdit->text().toInt()); query.addBindValue(ui->other_lineEdit->text().toInt()); query.addBindValue(c); query.exec(); } I use qt sdk 1.0.2. After building shows errors: Undefined reference to 'QSqlDatabase::addDatabase(QString const&, QString const&)... all errors is similar (Undefined reference to 'QSqlDatabase:: Do you have any idea how to repair it?

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  • Removing and restoring Window borders

    - by Laurence
    I want to remove the window borders of another process in C#; I used RemoveMenu to remove the borders. It almost works but I have 2 problems left: I need to remove the borders twice, the first time the menu bar still exists. I can’t restore the menu’s This is what I already wrote: public void RemoveBorders(IntPtr WindowHandle, bool Remove) { IntPtr MenuHandle = GetMenu(WindowHandle); if (Remove) { int count = GetMenuItemCount(MenuHandle); for (int i = 0; i < count; i++) RemoveMenu(MenuHandle, 0, (0x40 | 0x10)); } else { SetMenu(WindowHandle,MenuHandle); } int WindowStyle = GetWindowLong(WindowHandle, -16); //Redraw DrawMenuBar(WindowHandle); SetWindowLong(WindowHandle, -16, (WindowStyle & ~0x00080000)); SetWindowLong(WindowHandle, -16, (WindowStyle & ~0x00800000 | 0x00400000)); } Can someone show me what I did wrong? I already tried to save the MenuHandle and restore it later, but that doesn't work.

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  • XCode enum woes

    - by Raconteur
    Hi gang, I thought I had this sorted, but I am still missing something. Very simply, I have a Settings class that hold a DAO (sitting on a plist). I want to have a couple of enums for the settings for convenience and readability, such as GamePlayType and DifficultyLevel. Right now I am defining them in the Settings.h file above the @interface line as such: typedef enum { EASY, NORMAL, HARD } DifficultyLevel; and typedef enum { SET_NUMBER_OF_MOVES, TO_COMPLETION } GamePlayType; If I access them from within the Settings class like: - (int)gridSizeForLOD { switch ([self difficultyLevel]) { case EASY: return GRID_SIZE_EASY; case NORMAL: return GRID_SIZE_NORMAL; case HARD: return GRID_SIZE_HARD; default: return GRID_SIZE_NORMAL; } } everything is fine. But, if I try to access them outside of the Settings class, let's say in my main view controller class, like this: if (([settings gameType] == SET_NUMBER_OF_MOVES) && (numMoves == [settings numMovesForLOD])) { [self showLoseScreen]; } I get errors (like EXC_BAD_ACCESS) or the condition always fails. Am I doing something incorrectly? Also, I should point out that I have this code for the call to gameType (which lives in the Settings class): - (GamePlayType)gameType { return [dao gameType]; } and the DAO implements gameType like this: - (int)gameType { return (settingsContent != nil) ? [[settingsContent objectForKey:@"Game Type"] intValue] : 0; } I know I have the DAO returning an int instead of a GamePlayType, but A) the problem I am describing arose there when I tried to use the "proper" data type, and B) I did not think it would matter since the enum is just a bunch of named ints, right? Any help, greatly appreciated. I really want to understand this thoroughly, and something is eluding me... Cheers, Chris

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  • F# - POCO Class

    - by ebb
    Hey there! I'm trying to write a POCO class in proper F#... But something is wrong.. The C# code that I want to "translate" to proper F# is: public class MyTest { [Key] public int ID { get; set; } public string Name { get; set; } } The closest I can come to the above code in F# is something like: type Mytest() = let mutable _id : int = 0; let mutable _name : string = null; [<KeyAttribute>] member x.ID with public get() : int = _id and public set(value) = _id <- value member x.Name with public get() : string = _name and public set value = _name <- value However when I try to access the properties of the F# version it just returns a compile error saying "Lookup on object of indeterminate type based on information prior to this program point. A type annotation may be needed prior to this program point to constrain the type of the object. This may allow the lookup to be resolved." The code thats trying to get the property is a part of my Repository (I'm using EF Code First). module Databasethings = let GetEntries = let ctx = new SevenContext() let mydbset = ctx.Set<MyTest>() let entries = mydbset.Select(fun item -> item.Name).ToList() // This line comes up with a compile error at "item.Name" (the compile error is written above) entries What the hell is going on? Thanks in advance!

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  • When is a try catch not a try catch?

    - by Dearmash
    I have a fun issue where during application shutdown, try / catch blocks are being seemingly ignored in the stack. I don't have a working test project (yet due to deadline, otherwise I'd totally try to repro this), but consider the following code snippet. public static string RunAndPossiblyThrow(int index, bool doThrow) { try { return Run(index); } catch(ApplicationException e) { if(doThrow) throw; } return ""; } public static string Run(int index) { if(_store.Contains(index)) return _store[index]; throw new ApplicationException("index not found"); } public static string RunAndIgnoreThrow(int index) { try { return Run(index); } catch(ApplicationException e) { } return ""; } During runtime this pattern works famously. We get legacy support for code that relies on exceptions for program control (bad) and we get to move forward and slowly remove exceptions used for program control. However, when shutting down our UI, we see an exception thrown from "Run" even though "doThrow" is false for ALL current uses of "RunAndPossiblyThrow". I've even gone so far as to verify this by modifying code to look like "RunAndIgnoreThrow" and I'll still get a crash post UI shutdown. Mr. Eric Lippert, I read your blog daily, I'd sure love to hear it's some known bug and I'm not going crazy. EDIT This is multi-threaded, and I've verified all objects are not modified while being accessed

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  • Simple binary File I/O problem with cstdio(c++)

    - by Atilla Filiz
    The c++ program below fails to read the file. I know using cstdio is not good practice but that what I am used to and it should work anyway. $ ls -l l.uyvy -rw-r--r-- 1 atilla atilla 614400 2010-04-24 18:11 l.uyvy $ ./a.out l.uyvy Read 0 bytes out of 614400, possibly wrong file code: #include<cstdio> int main(int argc, char* argv[]) { FILE *fp; if(argc<2) { printf("usage: %s <input>\n",argv[0]); return 1; } fp=fopen(argv[1],"rb"); if(!fp) { printf("erör, cannot open %s for reading\n",argv[1]); return -1; } int bytes_read=fread(imgdata,1,2*IMAGE_SIZE,fp); //2bytes per pixel fclose(fp); if(bytes_read < 2*IMAGE_SIZE) { printf("Read %d bytes out of %d, possibly wrong file\n", bytes_read, 2*IMAGE_SIZE); return -1; } return 0; }

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  • Why would an image (the Mandelbrot) be skewed and wrap around?

    - by Sean D
    So I just wrote a little snippet to generate the Mandelbrot fractal and imagine my surprise when it came out all ugly and skewed (as you can see at the bottom). I'd appreciate a point in the direction of why this would even happen. It's a learning experience and I'm not looking for anyone to do it for me, but I'm kinda at a dead end debugging it. The offending generation code is: module Mandelbrot where import Complex import Image main = writeFile "mb.ppm" $ imageMB 1000 mandelbrotPixel x y = mb (x:+y) (0:+0) 0 mb c x iter | magnitude x > 2 = iter | iter >= 255 = 255 | otherwise = mb c (c+q^2) (iter+1) where q = x --Mandelbrot --q = (abs.realPart $ x) :+ (abs.imagPart $ x) --Burning Ship argandPlane x0 x1 y0 y1 width height = [(x,y)| y<-[y1,(y1-dy)..y0], --traverse from x<-[x0,(x0+dx)..x1]] --top-left to bottom-right where dx = (x1 - x0)/width dy = (y1 - y0)/height drawPicture :: (a->b->c)->(c->Colour)->[(a,b)]->Image drawPicture function colourFunction plane = map (colourFunction.uncurry function) plane imageMB s = createPPM s s $ drawPicture mandelbrotPixel (\x->[x,x,x]) $ argandPlane (-1.8) (-1.7) (0.02) 0.055 s' s' where s' = fromIntegral s And the image code (which I'm fairly confident in) is: module Image where type Colour = [Int] type Image = [Colour] createPPM :: Int -> Int -> Image -> String createPPM w h i = concat ["P3 ", show w, " ", show h, " 255\n", unlines.map (unwords.map show) $ i]

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  • creating an object within a function of a program

    - by user1066524
    could someone please tell me what I need to do in order to create an object in a function. I will try to explain by making up some sort of example... Let's say I have a program named TimeScheduler.cpp that implements the class Schedule.h (and I have the implementation in a separate file Schedule.cpp where we define the methods). In the declaration file we have declared two constructors Schedule(); //the default and Schedule(int, int, int);//accepts three arguments to get to the point--let's say in the main program file TimeScheduler.cpp we created our own functions in this program apart from the functions inherited from the class Schedule. so we have our prototypes listed at the top. /*prototypes*/ void makeSomeTime(); etc..... we have main(){ //etc etc... } we then define these program functions void makeSomeTime(){ //process } let's say that inside the function makeSomeTime(), we would like to create an array of Schedule objects like this Schedule ob[]={ summer(5,14, 49), fall(9,25,50) }; what do I have to do to the function makeSomeTime() in order for it to allow me to create this array of objects. The reason I ask is currently i'm having difficulty with my own program in that it WILL allow me to create this array of objects in main()....but NOT in a function like I just gave an example of. The strange thing is it will allow me to create a dynamic array of objects in the function..... like Schedule *ob = new Schedule[n+1]; ob[2]= Schedule(x,y,z); Why would it let me assign to a non-dynamic array in main(), but not let me do that in the function?

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  • GetIpAddrTable() leaks memory. How to resolve that?

    - by Stabledog
    On my Windows 7 box, this simple program causes the memory use of the application to creep up continuously, with no upper bound. I've stripped out everything non-essential, and it seems clear that the culprit is the Microsoft Iphlpapi function "GetIpAddrTable()". On each call, it leaks some memory. In a loop (e.g. checking for changes to the network interface list), it is unsustainable. There seems to be no async notification API which could do this job, so now I'm faced with possibly having to isolate this logic into a separate process and recycle the process periodically -- an ugly solution. Any ideas? // IphlpLeak.cpp - demonstrates that GetIpAddrTable leaks memory internally: run this and watch // the memory use of the app climb up continuously with no upper bound. #include <stdio.h> #include <windows.h> #include <assert.h> #include <Iphlpapi.h> #pragma comment(lib,"Iphlpapi.lib") void testLeak() { static unsigned char buf[16384]; DWORD dwSize(sizeof(buf)); if (GetIpAddrTable((PMIB_IPADDRTABLE)buf, &dwSize, false) == ERROR_INSUFFICIENT_BUFFER) { assert(0); // we never hit this branch. return; } } int main(int argc, char* argv[]) { for ( int i = 0; true; i++ ) { testLeak(); printf("i=%d\n",i); Sleep(1000); } return 0; }

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  • C++ linker unresolved external symbol (again;) from other source file *.obj file. (VC++ express)

    - by bua
    Hi there, I'm back to C/C++ after some break. I've a following problem: I've a solution where I've several projects (compilable and linkable). Now I need to add another project to this solution which depends on some sources from other projects. My new project compiles without any problems (I've added "existing sources" to my project). the error: 1>Linking... 1>LicenceManager.obj : error LNK2019: unresolved external symbol "int __cdecl saveLic(char *,struct Auth *)" (?saveLic@@YAHPADPAUAuth@@@Z) referenced in function "public: void __thiscall LicenceManager::generateLicence(int,char *)" (?generateLicence@LicenceManager@@QAEXHPAD@Z) 1>LicenceManager.obj : error LNK2019: unresolved external symbol "void __cdecl getSysInfo(struct Auth *)" (?getSysInfo@@YAXPAUAuth@@@Z) referenced in function "public: void __thiscall LicenceManager::generateLicence(int,char *)" (?generateLicence@LicenceManager@@QAEXHPAD@Z) Functions saveLic, and getSysInfo are defined in files which I've added to my new project from existing ones. There is object file created during compilation with those functions in target dir, but my LicenceManager class doesn't want to link. I use some extern "C" , and #pragma pack somewhere, but no more fancy stuff. I think every directory, lib and other necessary dependencies are visible in settings for this project. Thanks for any advice.

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  • C++: Maybe you know this fitfall?

    - by Martijn Courteaux
    Hi, I'm developing a game. I have a header GameSystem (just methods like the game loop, no class) with two variables: int mouseX and int mouseY. These are updated in my game loop. Now I want to access them from Game.cpp file (a class built by a header-file and the source-file). So, I #include "GameSystem.h" in Game.h. After doing this I get a lot of compile errors. When I remove the include he says of course: Game.cpp:33: error: ‘mouseX’ was not declared in this scope Game.cpp:34: error: ‘mouseY’ was not declared in this scope Where I want to access mouseX and mouseY. All my .h files have Header Guards, generated by Eclipse. I'm using SDL and if I remove the lines that wants to access the variables, everything compiles and run perfectly (*). I hope you can help me... This is the error-log when I #include "GameSystem.h" (All the code he is refering to works, like explained by the (*)): In file included from ../trunk/source/domein/Game.h:14, from ../trunk/source/domein/Game.cpp:8: ../trunk/source/domein/GameSystem.h:30: error: expected constructor, destructor, or type conversion before ‘*’ token ../trunk/source/domein/GameSystem.h:46: error: variable or field ‘InitGame’ declared void ../trunk/source/domein/GameSystem.h:46: error: ‘Game’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: ‘g’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘char’ ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘bool’ ../trunk/source/domein/FPS.h:46: warning: ‘void FPS_SleepMilliseconds(int)’ defined but not used This is the code which try to access the two variables: SDL_Rect pointer; pointer.x = mouseX; pointer.y = mouseY; pointer.w = 3; pointer.h = 3; SDL_FillRect(buffer, &pointer, 0xFF0000);

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  • Building argv and argc

    - by Wylie Coyote SG.
    I'm a student programmer using Qt to build a GUI application for work. The primary purpose of this application is to open some of our old style files, allows better editing and then save the file in a new format and file extension. Recently I have been asked to allow this conversion to take place from a terminal. While I do know what argv and argc are along with what they represent I am unsure how to accomplish what they want. For instance how to handle relative paths vs. absolute... maybe how to get absolute from relative; perhaps none of that is even needed. My programming experience has been primarily with guis so this is a little new to me. Users would like the following to be ran from the terminal application -o /fileLocation /fileDestination template(to determine new format) I began to use for loops and if statements to begin accomplishing this when I relized that I might be taking the worng approach to all of this. I WOULD ALSO BE REALLY INTERESTED IF QT HAS SOMETHING FOR THIS! Here is what I have began coming up with: int main(int argc, char *argv[]) { if(argc > 1) { for(int i = 0; i < argc; i++) { if(argv[i] == "-c") { QString fileName = QString::fromStdString(argv[i+1]); QString fileDestination = QString::fromStdString(argv[i+2]); QString templateName = QString::fromStdString(argv[i+3]); QFile fileToConvert(fileName); if(fileToConvert.open(QFile::ReadOnly)) { //do stuff Thanks for reading my post and a big thanks for any contributions you make to helping me overcome this issue.

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  • Reverse String Error?

    - by R41nB0w M47r1z
    I am creating this revese string App but i get a error if i include a space in the string ! #include <iostream> #include <string> using namespace std; int main() { int inputa; cout<<"%%%%%%%%%%%%%%%%%%String Reversing App%%%%%%%%%%%%%%%%%%%%%%%%"<<endl<<endl; cout<<"\nEnter 1 to continue and 0 to exit"<<endl<<endl; cin>>inputa; if(inputa!=0) { do { string a,c=""; cout<<"\nEnter the string you want to Reverse : "; cin>>a; for(int x=a.length()-1; x>=0; x--) { c=c+a.substr(x,1); } cout<<"\nThe Reverse String is : "<<c<<endl; cout<<"\nEnter 1 to continue and 0 to exit"<<endl<<endl; cin>>inputa; } while(inputa!=0); } //not my home work } If I type the following string like "abc def" there i get an error . But otherwise it works perfectly ! Is there some mistake with the codes ! I am new to CPP so it would be helpful if you could help me !

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  • ASP.NET MVC is not displaying the image

    - by Pinu
    <asp:Conte nt ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <%-- <h2>Notes</h2> <% Html.RenderPartial("~/Views/Shared/UserControl/Notes.ascx",Model.Notes); %> <br /> <h2>User Tracking Informtaion</h2> <% Html.RenderPartial("~/Views/Shared/UserControl/Tracking.ascx",Model.Log); %>--%> <div> <% for (int i = 1; i <= ViewData.Model.SelectedDocument.DocumentPages ; i++) { %> <br /> <img src="<%=DocuvaultMVC.Helpers.AppHelper.PDFUrl(ViewData.Model.SelectedDocument.DocumentID,i)%>" alt="Document" width="612" height="792" /> <%}%> <div> </div> </div> public static string PDFUrl(int id, int page) { return VirtualPathUtility.ToAbsolute("~/ViewDocument.aspx/" + id + "/" + page); }

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  • Getting functions of inherited functions to be called

    - by wrongusername
    Let's say I have a base class Animal from which a class Cow inherits, and a Barn class containing an Animal vector, and let's say the Animal class has a virtual function scream(), which Cow overrides. With the following code: Animal.h #ifndef _ANIMAL_H #define _ANIMAL_H #include <iostream> using namespace std; class Animal { public: Animal() {}; virtual void scream() {cout << "aaaAAAAAAAAAAGHHHHHHHHHH!!! ahhh..." << endl;} }; #endif /* _ANIMAL_H */ Cow.h #ifndef _COW_H #define _COW_H #include "Animal.h" class Cow: public Animal { public: Cow() {} void scream() {cout << "MOOooooOOOOOOOO!!!" << endl;} }; #endif /* _COW_H */ Barn.h #ifndef _BARN_H #define _BARN_H #include "Animal.h" #include <vector> class Barn { std::vector<Animal> animals; public: Barn() {} void insertAnimal(Animal animal) {animals.push_back(animal);} void tortureAnimals() { for(int a = 0; a < animals.size(); a++) animals[a].scream(); } }; #endif /* _BARN_H */ and finally main.cpp #include <stdlib.h> #include "Barn.h" #include "Cow.h" #include "Chicken.h" /* * */ int main(int argc, char** argv) { Barn barn; barn.insertAnimal(Cow()); barn.tortureAnimals(); return (EXIT_SUCCESS); } I get this output: aaaAAAAAAAAAAGHHHHHHHHHH!!! ahhh... How should I code this to get MOOooooOOOOOOOO!!! (and whatever other classes inheriting Animal wants scream() to be) instead?

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  • How can I include DBNull as a value in my strongly typed dataset?

    - by Beska
    I've created a strongly typed dataset (MyDataSet) in my .NET app. For the sake of simplicity, we'll say it has one DataTable (MyDataTable), with one column (MyCol). MyCol has its DataType property set to "System.Int32", and its AllowDBNull property set to "true". I'd like to manually create a new row, and add it to this dataset. I create the row without a problem, with something like: MyDataSet.MyDataTableRow myRow = MySimpleDataSet.MyDataTable.NewItemRow(); Fine. However, when I try to set the value to DBNull: myRow.MyCol = DBNull.Value; I'm told that I can't do it...that it can't cast that to an int. This makes sense, in a way, since I've defined it to be an int...but then how can I get DBNull in there? Am I not supposed to be able to have DBNull in there? Isn't that what the AllowDBNull property is for? I'm obviously missing something fundemental. Can someone help explain what it is? EDIT: I also tried entering "int?" as the DataType, but Visual Studio throws an error when I enter it, saying that "Column requires a valid DataType."

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  • upload new file first check if this file exist already in database or not then if not exist save that in database

    - by Hala Qaseam
    I'm trying to create sql database that contains Image Id (int) Imagename (varchar(50)) Image (image) and in aspx write in upload button this code: protected void btnUpload_Click(object sender, EventArgs e) { //Condition to check if the file uploaded or not if (fileuploadImage.HasFile) { //getting length of uploaded file int length = fileuploadImage.PostedFile.ContentLength; //create a byte array to store the binary image data byte[] imgbyte = new byte[length]; //store the currently selected file in memeory HttpPostedFile img = fileuploadImage.PostedFile; //set the binary data img.InputStream.Read(imgbyte, 0, length); string imagename = txtImageName.Text; //use the web.config to store the connection string SqlConnection connection = new SqlConnection(strcon); connection.Open(); SqlCommand cmd = new SqlCommand("INSERT INTO Image (ImageName,Image) VALUES (@imagename,@imagedata)", connection); cmd.Parameters.Add("@imagename", SqlDbType.VarChar, 50).Value = imagename; cmd.Parameters.Add("@imagedata", SqlDbType.Image).Value = imgbyte; int count = cmd.ExecuteNonQuery(); connection.Close(); if (count == 1) { BindGridData(); txtImageName.Text = string.Empty; ScriptManager.RegisterStartupScript(this, this.GetType(), "alertmessage", "javascript:alert('" + imagename + " image inserted successfully')", true); } } } When I'm uploading a new image I need to first check if this image already exists in database and if it doesn't exist save that in database. Please how I can do that?

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  • "for" loop from program 7.6 from Kochan's "Programming in Objective-C"

    - by Mr_Vlasov
    "The sigma notation is shorthand for a summation. Its use here means to add the values of 1/2^i, where i varies from 1 to n. That is, add 1/2 + 1/4 + 1/8 .... If you make the value of n large enough, the sum of this series should approach 1. Let’s experiment with different values for n to see how close we get." #import "Fraction.h" int main (int argc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; Fraction *aFraction = [[Fraction alloc] init]; Fraction *sum = [[Fraction alloc] init], *sum2; int i, n, pow2; [sum setTo: 0 over: 1]; // set 1st fraction to 0 NSLog (@"Enter your value for n:"); scanf ("%i", &n); pow2 = 2; for (i = 1; i <= n; ++i) { [aFraction setTo: 1 over: pow2]; sum2 = [sum add: aFraction]; [sum release]; // release previous sum sum = sum2; pow2 *= 2; } NSLog (@"After %i iterations, the sum is %g", n, [sum convertToNum]); [aFraction release]; [sum release]; [pool drain]; return 0; } Question: Why do we have to create additional variable sum2 that we are using in the "for" loop? Why do we need "release previous sum" here and then again give it a value that we just released? : sum2 = [sum add: aFraction]; [sum release]; // release previous sum sum = sum2; Is it just for the sake of avoiding memory leakage? (method "add" initializes a variable that is stored in sum2)

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  • Efficiently select top row for each category in the set

    - by VladV
    I need to select a top row for each category from a known set (somewhat similar to this question). The problem is, how to make this query efficient on the large number of rows. For example, let's create a table that stores temperature recording in several places. CREATE TABLE #t ( placeId int, ts datetime, temp int, PRIMARY KEY (ts, placeId) ) -- insert some sample data SET NOCOUNT ON DECLARE @n int, @ts datetime SELECT @n = 1000, @ts = '2000-01-01' WHILE (@n>0) BEGIN INSERT INTO #t VALUES (@n % 10, @ts, @n % 37) IF (@n % 10 = 0) SET @ts = DATEADD(hour, 1, @ts) SET @n = @n - 1 END Now I need to get the latest recording for each of the places 1, 2, 3. This way is efficient, but doesn't scale well (and looks dirty). SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 1 ORDER BY ts DESC ) t1 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 2 ORDER BY ts DESC ) t2 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 3 ORDER BY ts DESC ) t3 The following looks better but works much less efficiently (30% vs 70% according to the optimizer). SELECT placeId, ts, temp FROM ( SELECT placeId, ts, temp, ROW_NUMBER() OVER (PARTITION BY placeId ORDER BY ts DESC) rownum FROM #t WHERE placeId IN (1, 2, 3) ) t WHERE rownum = 1 The problem is, during the latter query execution plan a clustered index scan is performed on #t and 300 rows are retrieved, sorted, numbered, and then filtered, leaving only 3 rows. For the former query three times one row is fetched. Is there a way to perform the query efficiently without lots of unions?

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  • Function calculating the probability of a letter in an sentence

    - by Mike
    I have a function that is supposed to calculate the number of times a letter occurs in a sentence, and based on that, calculate the probability of it occurring in the sentence. To accomplish this, I have a sentence: The Washington Metropolitan Area is the most educated and affluent metropolitan area in the United States. An array of structures, containing the letter, the number of times it occurs, and the probability of it occurring, with one structure for each letter character and an additional structure for punctuation and spaces: struct letters { char letter; int occur; double prob; }box[53]; This is the function itself: void probability(letters box[53], int sum { cout<<sum<<endl<<endl; for(int c8=0;c8<26;c8++) { box[c8].prob = (box[c8].occur/sum); cout<<box[c8].letter<<endl; cout<<box[c8].occur<<endl; cout<<box[c8].prob<<endl<<endl; } } It correctly identifies that there are 90 letters in the sentence in the first line, prints out the uppercase letter as per the structure in the second line of the for loop, and prints out the number of times it occurs. It continually prints 0 for the probability. What am I doing wrong?

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  • MySQL query problem

    - by Luke
    Ok, I have the following problem. I have two InnoDB tables: 'places' and 'events'. One place can have many events, but event can be created without entering place. In this case event's foreign key is NULL. Simplified structure of the tables looks as follows: CREATE TABLE IF NOT EXISTS `events` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) COLLATE utf8_bin NOT NULL, `places_id` int(9) unsigned DEFAULT NULL, PRIMARY KEY (`id`), KEY `fk_events_places` (`places_id`), ) ENGINE=InnoDB; ALTER TABLE `events` ADD CONSTRAINT `events_ibfk_1` FOREIGN KEY (`places_id`) REFERENCES `places` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS `places` ( `id` int(9) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) COLLATE utf8_bin NOT NULL, PRIMARY KEY (`id`), ) ENGINE=InnoDB; Question is, how to construct query which contains name of the event and name of the corresponding place (or no value, in case there is no place assigned?). I am able to do it with two queries, but then I am visibly separating events which have place assigned from the ones that are without place. Help really appreciated.

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  • Blackberry - custom logic for checkboxes group

    - by SWATI
    if i click on any checkbox all previous checkboxes must get checked "my logic works" if i uncheck a checkbox then all checkboxes after it must get unchecked "how to do that" MyLogic works for storm but not for other models what to do //well what i want to do is i have 5 checkboxes class myscreen { chk_service = new CheckboxField[5]; chk_service[0]= new CheckboxField("1",true) chk_service[1]= new CheckboxField("2",false) chk_service[2]= new CheckboxField("3",false) chk_service[3]= new CheckboxField("4",false) chk_service[4]= new CheckboxField("5",false) CheckboxFieldChangeListener obj = new CheckboxFieldChangeListener(chk_service); chk_service[0].setChangeListener(obj); chk_service[1].setChangeListener(obj); chk_service[2].setChangeListener(obj); chk_service[3].setChangeListener(obj); chk_service[4].setChangeListener(obj); hm4 = new HorizontalFieldManager(); hm4.add(chk_service[0]); hm4.add(chk_service[1]); hm4.add(chk_service[2]); hm4.add(chk_service[3]); hm4.add(chk_service[4]); add(hm4); } public CheckboxFieldChangeListener (CheckboxField[] arrFields) { m_arrFields = arrFields; } public void fieldChanged(Field field, int context) { if(true == ((CheckboxField) field).getChecked()) { for(int i = 0; i < m_arrFields.length; i++) { if(m_arrFields[i]==field) { //a[j]=i; j++; break; } else { CheckboxField oField = m_arrFields[i]; oField.setChecked(true); } } } a[k] = j; if(false == ((CheckboxField) field).getChecked()) { for(int i =field.getIndex(); i < m_arrFields.length; i++) { if(m_arrFields[i]==field) { //a[j]=i; j++; break; } else { CheckboxField oField = m_arrFields[i]; oField.setChecked(false); } } } } }

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  • Asp.Net MVC3 - How create Dynamic DropDownList

    - by Bibo
    I found many articles on this but still I don´t know how exactly to do this. I am trying to create my own blog engine, I have View for create article (I am using EF and Code first) and now I must fill number of category in which article should be add but I want to change it to dropdownlist with names of categories. My model looks this: public class Article { public int ArticleID { get; set; } [Required] public string Title { get; set; } [Required] public int CategoryID { get; set; } public DateTime Date { get; set; } [Required()] [DataType(DataType.MultilineText)] [AllowHtml] public string Text { get; set; } public virtual Category Category { get; set; } public IEnumerable<SelectListItem> Categories { get; set; } public virtual ICollection<Comment> Comments { get; set; } } public class Category { public int CategoryID { get; set; } [Required] public string Name { get; set; } public virtual ICollection<Article> Articles { get; set; } } I know I must use Enum (or I think) but I am not exactly sure how. I don´t know which tutorial from that I found is best for me.

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  • How to use multiple identity numbers in one table?

    - by vincer
    I have an web application that creates printable forms, these forms have a unique number on them, the problem is I have 2 forms that separate numbers need to be created for them. ie) Form1- Numbered 2000000-2999999 Form2- Numbered 3000000-3999999 dbo.test2 - is my form information table Tsel - is my autoinc table for the 3000000 series numbers Tadv - is my autoinc table for the 2000000 series numbers What I have done is create 2 tables with just autoinc row (one for 2000000 series numbers and one for 3000000 series numbers), I then created a trigger to add a record to the coresponding table, read back the autoinc number and add it to my table that stores the form information including the just created autoinc number for the right series of forms. Although it does work, I'm concerned that the numbers will get messed up under load. I'm not sure the @@IDENTITY will always return the right value when many people are using the system. (I cannot have duplicates and I need to use the numbering form show above. See code below. ** TRIGGER ** CREATE TRIGGER MAKEANID2 ON dbo.test2 AFTER INSERT AS SET NOCOUNT ON declare @someid int declare @someid2 int declare @startfrom int declare @test1 varchar(10) select @someid=@@IDENTITY select @test1 = (Select name1 from test2 where sysid = @someid ) if @test1 = 'select' begin insert into Tsel Default values select @someid2 = @@IDENTITY end if @test1 = 'adv' begin insert into Tadv Default values select @someid2 = @@IDENTITY end update test2 set name2=(@someid2) where sysid = @someid SET NOCOUNT OFF

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  • streaming xml pretty printer in C/C++ using expat or libxml2?

    - by Mark Zeren
    I have a library that outputs xml without whitespace all on one line. In some cases I'd like to pretty print that output. I'm looking for a BSD-ish licensed C/C++ library or sample code that will take a raw xml byte stream and pretty print it. Here's some pseudo code showing one way that I might use this functionality: void my_write(const char* buf, int len); PrettyPrinter pp(bind(&my_write)); while (...) { // ... get some more xml ... const char* buf = xmlSource.get_buf(); int len = xmlSource.get_buf_len(); int written = pp.write(buf, len); // calls my_write with pretty printed xml // ... error handling, maybe call write again, etc. ... } I'd like to avoid instantiating a DOM representation. I already have dependencies on the expat and libxml2 shared libraries, and I'd rather not add any more shared library dependencies.

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