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• Is it a good idea to use an integer column for storing US ZIP codes in a database?

  - by Yadyn

  From first glance, it would appear I have two basic choices for storing ZIP codes in a database table: Text (probably most common), i.e. char(5) or varchar(9) to support +4 extension Numeric, i.e. 32-bit integer Both would satisfy the requirements of the data, if we assume that there are no international concerns. In the past we've generally just gone the text route, but I was wondering if anyone does the opposite? Just from brief comparison it looks like the integer method has two clear advantages: It is, by means of its nature, automatically limited to numerics only (whereas without validation the text style could store letters and such which are not, to my knowledge, ever valid in a ZIP code). This doesn't mean we could/would/should forgo validating user input as normal, though! It takes less space, being 4 bytes (which should be plenty even for 9-digit ZIP codes) instead of 5 or 9 bytes. Also, it seems like it wouldn't hurt display output much. It is trivial to slap a ToString() on a numeric value, use simple string manipulation to insert a hyphen or space or whatever for the +4 extension, and use string formatting to restore leading zeroes. Is there anything that would discourage using int as a datatype for US-only ZIP codes?

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• How to use dirent.h correctly.

  - by Nick

  Hello, I am new to C++ and I am experimenting with the dirent.h header to manipulate directory entries. The following little app compiles but pukes after you supple a directory name. Can someone give me a hint? The int quit is there to provide a while loop. I removed the loop in an attempt to isolate my problem. thanks! #include <iostream> #include <dirent.h> using namespace std; int main() { char *dirname = 0; DIR *pd = 0; struct dirent *pdirent = 0; int quit = 1; cout<< "Enter a directory path to open (leave blank to quit):\n"; cin >> dirname; if(dirname == NULL) { quit = 0; } pd = opendir(dirname); if(pd == NULL) { cout << "ERROR: Please provide a valid directory path.\n"; } return 0; }

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• C : files manipulation Can't figure out how to simplify this code with files manipulation.

  - by Bon_chan

  Hey guys, I have been working on this code but I can't find out what is wrong. This program does compile and run but it ends up having a fatal error. I have a file called myFile.txt, with the following content : James------ 07.50 Anthony--- 17.00 And here is the code : int main() { int n =2, valueTest=0,count=0; FILE* file = NULL; float temp= 00.00f, average= 00.00f, flTen = 10.00f; float *totalNote = (float*)malloc(n*sizeof(float)); int position = 0; char selectionNote[5+1], nameBuffer[10+1], noteBuffer[5+1]; file = fopen("c:\\myFile.txt","r"); fseek(file,10,SEEK_SET); while(valueTest<2) { fscanf(file,"%5s",&selectionNote); temp = atof(selectionNote); totalNote[position]= temp; position++; valeurTest++; } for(int counter=0;counter<2;counter++) { average += totalNote[counter]; } printf("The total is : %f \n",average); rewind(file); printf("here is the one with less than 10.00 :\n"); while(count<2) { fscanf(file,"%10s",&nameBuffer); fseek(file,10,SEEK_SET); fscanf(file,"%5s",&noteBuffer); temp = atof(noteBuffer); if(temp<flTen) { printf("%s who has %f\n",nameBuffer,temp); } fseek(file,1,SEEK_SET); count++; } fclose(file); } I am pretty new to c and find it more difficult than c# or java. And I woud like to get some suggestions to help me to get better. I think this code could be simplier. Do you think the same ?

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• Identity.Name is disposed in a IIS7 Asp.NET MVC application Thread

  - by vIceBerg

  I have made the smallest demo project to illustrate my problem. You can download the sources Here Visual Studio 2008, .NET 3.5, IIS7, Windows 7 Ultimate 32 bits. The IIS Website is configured ONLY for Windows Authentication in an Integreated pipeline app pool (DefaultAppPool). Here's the problem. I have an Asp.NET MVC 2 application. In an action, I start a thread. The View returns. The thread is doing it's job... but it needs to access Thread.CurrentPrincipal.Identity.Name BANG The worker process of IIS7 stops. I have a window that says: "Visual Studio Just-In-Time Debugger An unhandled exception ('System.Object.DisposedException') occured in w3wp.exe [5524]" I checked with the debugger and the Thread.CurrentPrincipal.Identity is valid, but the Name property is disposed. If I put a long wait in the action before it returns the view, then the Thread can do it's job and the Identity.Name is not disposed. So I think the Name gets disposed when the view is returned. For the sake of the discussion, here's the code that the thread runs (but you can also download the demo project. The link is on top of this post): private void Run() { const int SECTOWAIT = 3; //wait SECTOWAIT seconds long end = DateTime.Now.Ticks + (TimeSpan.TicksPerSecond * SECTOWAIT); while (DateTime.Now.Ticks <= end) continue; //Check the currentprincipal. BANG!!!!!!!!!!!!! var userName = Thread.CurrentPrincipal.Identity.Name; } Here's the code that starts the thread public void Start() { Thread thread = new Thread(new ParameterizedThreadStart(ThreadProc)); thread.SetApartmentState(ApartmentState.MTA); thread.Name = "TestThread"; thread.Start(this); } static void ThreadProc(object o) { try { Builder builder = (Builder)o; builder.Run(); } catch (Exception ex) { throw; } } So... what am i doing wrong? Thanks

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• Obj-C: Passing pointers to initialized classes in other classes

  - by FnGreg7

  Hey all. I initialized a class in my singleton called DataModel. Now, from my UIViewController, when I click a button, I have a method that is trying to access that class so that I may add an object to one of its dictionaries. My get/set method passes back the pointer to the class from my singleton, but when I am back in my UIViewController, the class passed back doesn't respond to methods. It's like it's just not there. I think it has something to do with the difference in passing pointers around classes or something. I even tried using the copy method to throw a copy back, but no luck. UIViewController: ApplicationSingleton *applicationSingleton = [[ApplicationSingleton alloc] init]; DataModel *dataModel = [applicationSingleton getDataModel]; [dataModel retrieveDataCategory:dataCategory]; Singleton: ApplicationSingleton *m_instance; DataModel *m_dataModel; - (id) init { NSLog(@"ApplicationSingleton.m initialized."); self = [super init]; if(self != nil) { if(m_instance != nil) { return m_instance; } NSLog(@"Initializing the application singleton."); m_instance = self; m_dataModel = [[DataModel alloc] init]; } NSLog(@"ApplicationSingleton init method returning."); return m_instance; } -(DataModel *)getDataModel { DataModel *dataModel_COPY = [m_dataModel copy]; return dataModel_COPY; } For the getDataModel method, I also tried this: -(DataModel *)getDataModel { return m_dataModel; } In my DataModel retrieveDataCategory method, I couldn't get anything to work. I even just tried putting a NSLog in there but it never would come onto the console. Any ideas?

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• Other test cases for this openFile function?

  - by igor

  I am trying to figure out why my function to open a file is failing this autograder I submit my homework into. What type of input would fail here, I can't think of anything else? Code: bool openFile(ifstream& ins) { char fileName[256]; cout << "Enter board filename: "; cin.getline(fileName,256); cout << endl << fileName << endl; ins.open(fileName); if(!ins) { ins.clear(); cout<<"Error opening file"<<endl; return false; } return true; } Here is output from the 'Autograder' of what my program's output is, and what the correct output is supposed to be (and I do not know what is in the file they use for the input) Autograder output: ******************************************* ***** ***** ***** Your output is: ***** ***** ***** ******************************************* Testing function openFile Enter board filename: test.txt 1 Enter board filename: not a fileName Error opening file 0 ******************************************* ***** ***** ***** Correct Output ***** ***** ***** ******************************************* Testing function openFile Enter board filename: 1 Enter board filename: Error opening file 0

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• Who's setting TCP window size down to 0, Indy or Windows?

  - by François

  We have an application server which have been observed sending headers with TCP window size 0 at times when the network had congestion (at a client's site). We would like to know if it is Indy or the underlying Windows layer that is responsible for adjusting the TCP window size down from the nominal 64K in adaptation to the available throughput. And we would be able to act upon it becoming 0 (nothing gets send, users wait = no good). So, any info, link, pointer to Indy code are welcome... Disclaimer: I'm not a network specialist. Please keep the answer understandable for the average me ;-) Note: it's Indy9/D2007 on Windows Server 2003 SP2. More gory details: The TCP zero window cases happen on the middle tier talking to the DB server. It happens at the same moments when end users complain of slowdowns in the client application (that's what triggered the network investigation). 2 major Network issues causing bottlenecks have been identified. The TCP zero window happened when there was network congestion, but may or may not be caused by it. We want to know when that happen and have a way to do something (logging at least) in our code. So where to hook (in Indy?) to know when that condition occurs?

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• JNI Stream binary data from C++ to Java

  - by Cliff

  I need help passing binary data into Java. I'm trying to use jbytearray but when the data gets into Java it appears corrupt. Can somebody give me a hand? Here's a snip of some example code. First the native C++ side: printf("Building audio array copy\n"); jbyteArray rawAudioCopy = env-NewByteArray(10); jbyte toCopy[10]; printf("Filling audio array copy\n"); char theBytes[10] = {0,1,2,3,4,5,6,7,8,9}; for (int i = 0; i < sizeof(theBytes); i++) { toCopy[i] = theBytes[i]; } env->SetByteArrayRegion(rawAudioCopy,0,10,toCopy); printf("Finding object callback\n"); jmethodID aMethodId = env->GetMethodID(env->GetObjectClass(obj),"handleAudio","([B)V"); if(0==aMethodId) throw MyRuntimeException("Method not found error",99); printf("Invoking the callback\n"); env->CallVoidMethod(obj,aMethodId, &rawAudioCopy); and then the Java callback method: public void handleAudio(byte[] audio){ System.out.println("Audio supplied to Java [" + audio.length + "] bytes"); byte[] expectedAudio = {0,1,2,3,4,5,6,7,8,9}; for (int i = 0; i < audio.length; i++) { if(audio[i]!= expectedAudio[i]) System.err.println("Expected byte " + expectedAudio[i] + " at byte " + i + " but got byte " + audio[i]); else System.out.print('.'); } System.out.println("Audio passed back accordingly!"); } I get the following output when the callback is invoked: library loaded! Audio supplied to Java [-2019659176] bytes Audio passed back accordingly!

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• How is external memory, internal memory, and cache organized?

  - by goldenmean

  Consider a system as follows:= A hardware board having say ARM Cortex-A8 and Neon Vector coprocessor, and Embedded Linux OS running on Cortex-A8. On this environment, if there is some application - say, a video decoder is executing - then: How is it decided that which buffers would be in external memory, which ones would be allocated in internal SRAM, etc. When one says calloc/malloc on such system/code, the pointer returned is from which memory: internal or external? Can a user make buffers to be allocated to the memories of his choice (internal/external)? In ARM architectures, there is another memory called as Tightly coupled memory (TCM). What is that and how can user enable and use it? Can I declare buffers in this memory? Do I need to see the memory map (if any) of the hardware board to understand about all these different physical memories present in a typical hardware board? How much of a role does the OS play in distinguishing these different memories? Sorry for multiple questions, but i think they all are interlinked.

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• Approaches to replace cursor in pure AS3 / Flare project?

  - by peteorpeter

  Hi there good lookin, I've got a pure AS3 (no Flex) project that uses Flare to display and interact with a data visualization. I just implemented some panning behavior, so you can click and drag the visualization around, and now I'd like to give the user a visual indicator that this is possible, by switching the arrow cursor with a nice grabby-looking hand icon. The user can click and drag at any time except when the mouse is over a clickable node (at which time the cursor swaps to a pointer - this behavior is already in place). So... 1) Do I need to create my own custom bitmap/sprite or is there a palette of built-in cursors I can use? (I'm not using Flex.) 2) Is there a way to simply replace the default arrow with the pan cursor project-wide, or do I need to attach the swapping to mouse events on display objects? Can I use the stage object to make this behavior apply everywhere? 3) How do I perform the swap? Do I use the Cursor object directly or do I need to get involved with the CursorManager? Any guidance, pseudo-code, or words of wisdom is greatly appreciated!

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• how do i insert html file that have hebrew text and read it back in sql server 2008 using the filest

  - by gadym

  hello all, i am new to the filestream option in sql server 2008, but i have already understand how to open this option and how to create a table that allow you to save files. let say my table contains: id,name, filecontent i tried to insert an html file (that has hebrew chars/text in it) to this table. i'm writing in asp.net (c#), using visual studio 2008. but when i tried to read back the content , hebrew char becomes '?'. the actions i took were: 1. i read the file like this: // open the stream reader System.IO.StreamReader aFile = new StreamReader(FileName, System.Text.UTF8Encoding.UTF8); // reads the file to the end stream = aFile.ReadToEnd(); // closes the file aFile.Close(); return stream; // returns the stream i inserted the 'stream' to the filecontent column as binary data. i tried to do a 'select' to this column and the data did return (after i coverted it back to string) but hebrew chars become '?' how do i solve this problem ? what I should pay attention to ? thanks, gadym

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• Storing header and data sections in a CSV file

  - by morpheous

  This should be relatively easy to do, but after several hours straight programming my mind seems a bit frazzled and could do with some help. I have a C++ class which I am currently using to store read/write data to file. I was initially using binary data, but have decided to store the data as CSV in order to let programs written in other languages be able to load the data. The C++ class looks a bit like this: class BinaryData { public: BinaryData(); void serialize(std::ostream& output) const; void deserialize(std::istream& input); private: Header m_hdr; std::vector<Row> m_rows; }; I am simply rewriting the serialize/deserialize methods to write to a CSV file. I am not sure on the "best" way to store a header section and a "data" section in a "flat" CSV file though - any suggestions on the most sensible way to do this?

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• Is it possible to get the parsed text of a SqlCommand with SqlParameters?

  - by Burg

  What I am trying to do is create some arbitrary sql command with parameters, set the values and types of the parameters, and then return the parsed sql command - with parameters included. I will not be directly running this command against a sql database, so no connection should be necessary. So if I ran the example program below, I would hope to see the following text (or something similar): WITH SomeTable (SomeColumn) AS ( SELECT N':)' UNION ALL SELECT N'>:o' UNION ALL SELECT N'^_^' ) SELECT SomeColumn FROM SomeTable And the sample program is: using System; using System.Data; using System.Data.SqlClient; namespace DryEraseConsole { class Program { static void Main(string[] args) { const string COMMAND_TEXT = @" WITH SomeTable (SomeColumn) AS ( SELECT N':)' UNION ALL SELECT N'>:o' UNION ALL SELECT @Value ) SELECT SomeColumn FROM SomeTable "; SqlCommand cmd = new SqlCommand(COMMAND_TEXT); cmd.CommandText = COMMAND_TEXT; cmd.Parameters.Add(new SqlParameter { ParameterName = "@Value", Size = 128, SqlDbType = SqlDbType.NVarChar, Value = "^_^" }); Console.WriteLine(cmd.CommandText); Console.ReadKey(); } } } Is this something that is achievable using the .net standard libraries? Initial searching says no, but I hope I'm wrong.

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• Java: Help constructing a fillTextFields() method

  - by Holly

  I have a Java project where I am to connect to a database and create buttons (next, new, save, delete, previous) to navigate through the database content where there are appropriate text fields and labels for the specific information. I'll use the code below as an example (each button is set up very similar)... I have it as follows: JButton jbtnNext = new JButton("Next ->"); jbtnNext.addActionListener(this); if (e.getSource() == jbtnNext) jbtnNext_Click(); private void jbtnNext_Click() { JOptionPane.showMessageDialog(null, "Next" ,"Button Pressed", JOptionPane.INFORMATION_MESSAGE); try { if (rset.next()) { fillTextFields(true); }else{ //Display result in a dialog box JOptionPane.showMessageDialog(null, "Not found"); } } catch (SQLException ex) { ex.printStackTrace(); } } The professor gave the following outline of logic to construct the fillTextFields() method: Construct the method to provide reusable code that would fill the JTextFields on the GUI with appropriate values from current record from the database (when "Previous or "Next" buttons are pressed) or blank values (when the new Button is pressed). To determine when the current record was to provide values (next and previous) or the value would be blank (new button) pass a boolean argument into the method. If data from the current record was to be used as fill values, pass true for both previous and next button code after moving the record pointer. If the new button was pressed and want to fill with blank values, pass false to the method. Inside the method, use a conditional expression to evaluate the boolean variable. If true, The appropriate get----() resultset method is used to fill the JTextFields. If false, fill them with "". The .setText() method of the JTextField is used to fill each JTextField. Make sure the fillTextFields method throws the appropriate exception. I understand and have the previous and next button methods passing true, while the new button method is passing false, but I don't quite understand how to set up the fillTextFields() method correctly or how to "throw the appropriate exception"... Any help would really be appreciated, thank you!

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• How to extract ALL typedefs and structs and unions from c++ source

  - by Michael Wells

  I have inherited a Visual Studio project that contains hundreds of files. I would like to extract all the typedefs, structs and unions from each .h/.cpp file and put the results in a file). Each typdef/struct/union should be on one line in the results file. This would make sorting much easier. typdef int myType; struct myFirstStruct { char a; int b;...}; union Part_Number_Serial_Number_Part_2_Response_Message_Type {struct{Message_Response_Head_Type Head; Part_Num_Serial_Num_Part_2_Report_Array Part_2_Report; Message_Tail_Type Tail;} Data; BYTE byData[140];}myUnion; struct { bool c; int d;...}mySecondStruct; My problem is, I do not know what to look for (grammar of typedef/structs/unions) using a regular expression. I cannot believe that nobody has done this before (I googled and have not found anything on this). Does anyone know the regular expressions for these? (Note some are commented out using // others /* */) Or a tool to accomplish this. Edit: I am toying with the idea of autogenerating source code and/or dialogs for modifying messages that use the underlying typedef/struct/union. I was going to use the output to generate an XML file that could be used for this reason. The source for these are in C/C++ and used in almost all my projects. These projects are usually NOT in C/C++. By using the XML version I would only need to update/add the typedef/struct/union only in one place and all the projects would be able to autogen the source and/or dialogs.

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• Newbie: Render RGB to GTK widget -- howto?

  - by Billy Pilgrim

  Hi All, Big picture: I want to render an RGB image via GTK on a linux box. I'm a frustrated GTK newbie, so please forgive me. I assume that I should create a Drawable_area in which to render the image -- correct? Do I then have to create a graphics context attached to that area? How? my simple app (which doesn't even address the rgb issue yet is this: int main(int argc, char** argv) { GdkGC * gc = NULL; GtkWidget * window = NULL; GtkDrawingArea * dpage = NULL; GtkWidget * page = NULL; gtk_init( &argc, & argv ); window = gtk_window_new( GTK_WINDOW_TOPLEVEL ); page = gtk_drawing_area_new( ); dpage = GTK_DRAWING_AREA( page ); gtk_widget_set_size_request( page, PAGE_WIDTH, PAGE_HEIGHT ); gc = gdk_gc_new( GTK_DRAWABLE( dpage ) ); gtk_widget_show( window ); gtk_main(); return (EXIT_SUCCESS); } my dpage is apparently not a 'drawable' (though it is a drawing area). I am confused as to a) how do I get/create the graphics context which is required in subsequent function calls? b) am I close to a solution, or am I so completely *#&@& wrong that there is no hope c) a baby steps tutorial. (I started with hello world as my base, so I got that far). any and all help appreciated. bp

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• CSS style submit like href tag

  - by seth.vargo

  Hi all, I have a button class that I wrote in CSS. It essentially displays block, adds some styles, etc. Whenever I add the class to a tags, it works fine - the a tag spans the entire width of its container like display:block should do... However, when I add the button class to an input button, Chrome, Safari, and Firefox all add a margin-right: 3px... I've used the DOM inspector in both Chrome and Safari and NO WHERE should it be adding a extra 3px padding. I tried adding margin: 0 !important; and/or margin-right: 0 !important to my button class in my CSS, but the browser STILL renders a 3px right margin! Is this a known issue, and is there a CSS-based solution (i.e. not jQuery/javascript) CODE FOLLOWS: .button { position: relative; display: block; margin: 0; border: 1px solid #369; color: #fff; font-weight: bold; padding: 11px 20px; line-height: 18px; text-align: center; text-transform: uppercase; cursor: hand; cursor: pointer; }

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• WYSIWYG with Qt - font size woes

  - by Rob

  I am creating a custom Qt widget that mimics an A4 printed page and am having problems getting fonts to render at the correct size. My widget uses QPainter::setViewport and QPainter::setWindow to mimic the A4 page, using units of 10ths of a millimetre which enables me to draw easily. However, attempting to create a font at a specific point size doesn't seem to work and using QFont:setPixelSize isn't accurate. Here is some code: View::View(QWidget *parent) : QWidget(parent), printer(new QPrinter) { printer->setPaperSize(QPrinter::A4); printer->setFullPage(true); } void View::paintEvent(QPaintEvent*) { QPainter painter(this); painter.setWindow(0, 0, 2100, 2970); painter.setViewport(0, 0, printer->width(), printer->height()); // Draw a rect at x = 1cm, y = 1cm, 6cm wide and 1 inch high painter.drawRect(100, 100, 600, 254); // Create a 72pt (1 inch) high font QFont font("Arial"); font.setPixelSize(254); painter.setFont(font); // Draw in the same box // The font is too large painter.drawText(QRect(100, 100, 600, 254), tr("Wg\u0102")); // Ack - the actual font size reported by the metrics is 283 pixels! const QFontMetrics fontMetrics = painter.fontMetrics(); qDebug() << "Font height = " << fontMetrics.height(); } So I'm asking for a 254 high font (1 inch, 72 pts) and it's too big and sure enough when I query for the font height via QFontMetrics it is 283 high. Does anyone else know how to use font sizes in points when using custom mapping modes like this? It must be possible. Note that I cannot see how to convert between logical/device points either (i.e. the Win32 DPtoLP/LPtoDP equivalents.)

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• Do all C compilers allow functions to return structures?

  - by Jordan S

  I am working on a program in C and using the SDCC compiler for a 8051 architecture device. I am trying to write a function called GetName that will read 8 characters from Flash Memory and return the character array in some form. I know that it is not possible to return an array in C so I am trying to do it using a struct like this: //********************FLASH.h file******************************* MyStruct GetName(int i); //Function prototype #define NAME_SIZE 8 typedef struct { char Name[NAME_SIZE]; } MyStruct; extern MyStruct GetName(int i); // *****************FLASH.c file*********************************** #include "FLASH.h" MyStruct GetName( int i) { MyStruct newNameStruct; //... // Fill the array by reading data from Flash //... return newNameStruct; } I don't have any references to this function yet but for some reason, I get a compiler error that says "Function cannot return aggregate." Does this mean that my compiler does not support functions that return structs? Or am I just doing something wrong?

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• How do I break down an NSTimeInterval into year, months, days, hours, minutes and seconds on iPhone?

  - by willc2

  I have a time interval that spans years and I want all the time components from year down to seconds. My first thought is to integer divide the time interval by seconds in a year, subtract that from a running total of seconds, divide that by seconds in a month, subtract that from the running total and so on. That just seems convoluted and I've read that whenever you are doing something that looks convoluted, there is probably a built-in method. Is there? I integrated Alex's 2nd method into my code. It's in a method called by a UIDatePicker in my interface. NSDate *now = [NSDate date]; NSDate *then = self.datePicker.date; NSTimeInterval howLong = [now timeIntervalSinceDate:then]; NSDate *date = [NSDate dateWithTimeIntervalSince1970:howLong]; NSString *dateStr = [date description]; const char *dateStrPtr = [dateStr UTF8String]; int year, month, day, hour, minute, sec; sscanf(dateStrPtr, "%d-%d-%d %d:%d:%d", &year, &month, &day, &hour, &minute, &sec); year -= 1970; NSLog(@"%d years\n%d months\n%d days\n%d hours\n%d minutes\n%d seconds", year, month, day, hour, minute, sec); When I set the date picker to a date 1 year and 1 day in the past, I get: 1 years 1 months 1 days 16 hours 0 minutes 20 seconds which is 1 month and 16 hours off. If I set the date picker to 1 day in the past, I am off by the same amount. Update: I have an app that calculates your age in years, given your birthday (set from a UIDatePicker), yet it was often off. This proves there was an inaccuracy, but I can't figure out where it comes from, can you?

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• Multi-reader IPC solution?

  - by gct

  I'm working on a framework in C++ (just for fun for now), that lets the user write plugins that use a standard API to stream data between each other. There's going to be three basic transport mechanisms for the data: files, sockets, and some kind of IPC piping system. The system is set up so that for the non-file transport, each stream can have multiple readers. IE once a server socket it setup, multiple computers can connect and stream the data. I'm a little stuck at the multi-reader IPC system though. All my plugins run in threads so they live in the same address space, so some kind of shared memory system would work fine, I was thinking I'd write my own circular buffer with a write pointer and read pointers chassing it around the buffer, but I have my doubts that I can achieve the same performance as something like linux pipes. I'm curious what people would suggest for a multi-reader solution to something like this? Is the overhead for pipes or domain sockets low enough that I could just open a connection to each reader and issue separate writes to each reader? This is intended to be significant volumes of data (tens of mega-samples/sec), so performance is a must.

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• confusion about using types instead of gtts in oracle

  - by Omnipresent

  I am trying to convert queries like below to types so that I won't have to use GTT: insert into my_gtt_table_1 (house, lname, fname, MI, fullname, dob) (select house, lname, fname, MI, fullname, dob from (select 'REG' house, mbr_last_name lname, mbr_first_name fname, mbr_mi MI, mbr_first_name || mbr_mi || mbr_last_name fullname, mbr_dob dob from table_1 a, table_b where a.head = b.head and mbr_number = '01' and mbr_last_name = v_last_name) c above is just a sample but complex queries are bigger than this. the above is inside a stored procedure. So to avoid the gtt (my_gtt_table_1). I did the following: create or replace type lname_row as object ( house varchar2(30) lname varchar2(30), fname varchar2(30), MI char(1), fullname VARCHAR2(63), dob DATE ) create or replace type lname_exact as table of lname_row Now in the SP: type lname_exact is table of <what_table_should_i_put_here>%rowtype; tab_a_recs lname_exact; In the above I am not sure what table to put as my query has nested subqueries. query in the SP: (I am trying this for sample purpose to see if it works) select lname_row('', '', '', '', '', '', sysdate) bulk collect into tab_a_recs from table_1; I am getting errors like : ORA-00913: too many values I am really confused and stuck with this :(

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• How to partition bits in a bit array with less than linear time

  - by SiLent SoNG

  This is an interview question I faced recently. Given an array of 1 and 0, find a way to partition the bits in place so that 0's are grouped together, and 1's are grouped together. It does not matter whether 1's are ahead of 0's or 0's are ahead of 1's. An example input is 101010101, and output is either 111110000 or 000011111. Solve the problem in less than linear time. Make the problem simpler. The input is an integer array, with each element either 1 or 0. Output is the same integer array with integers partitioned well. To me, this is an easy question if it can be solved in O(N). My approach is to use two pointers, starting from both ends of the array. Increases and decreases each pointer; if it does not point to the correct integer, swap the two. int * start = array; int * end = array + length - 1; while (start < end) { // Assume 0 always at the end if (*end == 0) { --end; continue; } // Assume 1 always at the beginning if (*start == 1) { ++start; continue; } swap(*start, *end); } However, the interview insists there is a sub-linear solution. This makes me thinking hard but still not get an answer. Can anyone help on this interview question?

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• Sqlite iPhone data insertion problem

  - by Asad Khan

  Hi I have a function which basically tries to insert some data returned from a REST call. - (void)syncLocalDatabase{ NSString *file = [[NSBundle mainBundle] pathForResource:@"pickuplines" ofType:@"db"]; NSMutableString *query = [[NSMutableString alloc] initWithFormat:@""]; sqlite3 *database = NULL; char *errorMsg = NULL; if (sqlite3_open([file UTF8String], &database) == SQLITE_OK) { for(PickUpLine *pickupline in pickUpLines){ [query appendFormat:@"INSERT INTO pickuplines VALUES(%d,%d,%d,'%@','YES')", pickupline.line_id, pickupline.thumbsUps, pickupline.thumbsDowns, [pickupline.line stringByReplacingOccurrencesOfString:@"'" withString:@"`"]]; NSLog(query); int result = sqlite3_exec(database, [query UTF8String], NULL, NULL, &errorMsg); if (result!=SQLITE_OK) { printf("\n%s",errorMsg); sqlite3_free(errorMsg); } //sqlite3_step([query UTF8String]); [query setString:@""]; }//end for }//end if [query release]; sqlite3_close(database); } everything seems fine query string in log statement is also fine but the data does not gets inserted. Where as a counterpart of this function for select statement works well. Here is the counter part - (void)loadLinesFromDatabase{ NSString *file = [[NSBundle mainBundle] pathForResource:@"pickuplines" ofType:@"db"]; sqlite3 *database = NULL; if (sqlite3_open([file UTF8String], &database) == SQLITE_OK) { sqlite3_exec(database, "SELECT * FROM pickuplines", MyCallback, linesFromDatabase, NULL); } sqlite3_close(database); } I have implemented callback & it works fine. I am a little new to Sqlite can someone please point out what am I doing wrong. Thanx

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• static variable lose its value

  - by user542719

  I have helper class with this static variable that is used for passing data between two classes. public class Helper{ public static String paramDriveMod;//this is the static variable in first calss } this variable is used in following second class mathod public void USB_HandleMessage(char []USB_RXBuffer){ int type=USB_RXBuffer[2]; MESSAGES ms=MESSAGES.values()[type]; switch(ms) { case READ_PARAMETER_VALUE: // read parameter values switch(prm){ case PARAMETER_DRIVE_MODE: // paramet drive mode Helper.paramDriveMod =(Integer.toString(((USB_RXBuffer[4]<< 8)&0xff00))); System.out.println(Helper.paramDriveMod+"drive mode is selectd ");//here it shows the value that I need. ..........}}//let say end switch and method and the following is an third class method use the above class method public void buttonSwitch(int value) throws InterruptedException{ boolean bool=true; int c=0; int delay=(int) Math.random(); while(bool){ int param=3; PARAMETERS prm=PARAMETERS.values()[param]; switch(value){ case 0: value=1; while(c<5){ Thread.sleep(delay); protocol.onSending(3,prm.PARAMETER_DRIVE_MODE.ordinal(),dataToRead,dataToRead.length);//read drive mode System.out.println(Helper.paramDriveMod+" drive mode is ..........in wile loop");//here it shows null value }}//let say end switch and method what is the reason that this variable lose its value?

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