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  • Linkage Error with Inherited Class

    - by metdos
    I have static library and another program which uses it. In the static library If I define header without inheretence it works fine. class TcpCommunication On the other hand If I use inheretence with a QT class, class TcpCommunication:public QTcpServer I'm getting linkage error when I compiling code which uses this static library. >MStoDKAPId.lib(TcpCommunication.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __thiscall QTcpServer::~QTcpServer(void)" (__imp_??1QTcpServer@@UAE@XZ) referenced in function "public: virtual __thiscall TcpCommunication::~TcpCommunication(void)" (??1TcpCommunication@@UAE@XZ) What can be the problem? Thanks.

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  • Check if a type is an instantiation of a template

    - by Pedro Lacerda
    I have structs like struct RGBA (T) {/* ... */} struct BMPFile (DataT) if (is(DataT == RGBA)) {/* ... */} But is(DataT == RGBA) cannot work because DataT is a type and RGBA is a template. Instead I need check if a type is an instantiation of a template in order to declare file like BMPFile!(RGBA!ushort) file; In a comment @FeepingCreature showed struct RGBA(T) { alias void isRGBAStruct; } struct BMPFile (DataT) if (is(DataT.isRGBAStruct)) {} Although to be working I have no tips on alias void isRGBAStruct.

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  • Help with code optimization

    - by Ockonal
    Hello, I've written a little particle system for my 2d-application. Here is raining code: // HPP ----------------------------------- struct Data { float x, y, x_speed, y_speed; int timeout; Data(); }; std::vector<Data> mData; bool mFirstTime; void processDrops(float windPower, int i); // CPP ----------------------------------- Data::Data() : x(rand()%ScreenResolutionX), y(0) , x_speed(0), y_speed(0), timeout(rand()%130) { } void Rain::processDrops(float windPower, int i) { int posX = rand() % mWindowWidth; mData[i].x = posX; mData[i].x_speed = WindPower*0.1; // WindPower is float mData[i].y_speed = Gravity*0.1; // Gravity is 9.8 * 19.2 // If that is first time, process drops randomly with window height if (mFirstTime) { mData[i].timeout = 0; mData[i].y = rand() % mWindowHeight; } else { mData[i].timeout = rand() % 130; mData[i].y = 0; } } void update(float windPower, float elapsed) { // If this is first time - create array with new Data structure objects if (mFirstTime) { for (int i=0; i < mMaxObjects; ++i) { mData.push_back(Data()); processDrops(windPower, i); } mFirstTime = false; } for (int i=0; i < mMaxObjects; i++) { // Sleep until uptime > 0 (To make drops fall with randomly timeout) if (mData[i].timeout > 0) { mData[i].timeout--; } else { // Find new x/y positions mData[i].x += mData[i].x_speed * elapsed; mData[i].y += mData[i].y_speed * elapsed; // Find new speeds mData[i].x_speed += windPower * elapsed; mData[i].y_speed += Gravity * elapsed; // Drawing here ... // If drop has been falled out of the screen if (mData[i].y > mWindowHeight) processDrops(windPower, i); } } } So the main idea is: I have some structure which consist of drop position, speed. I have a function for processing drops at some index in the vector-array. Now if that's first time of running I'm making array with max size and process it in cycle. But this code works slower that all another I have. Please, help me to optimize it. I tried to replace all int with uint16_t but I think it doesn't matter.

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  • Java Flow Control Problem

    - by Kyle_Solo
    I am programming a simple 2d game engine. I've decided how I'd like the engine to function: it will be composed of objects containing "events" that my main game loop will trigger when appropriate. A little more about the structure: Every GameObject has an updateEvent method. objectList is a list of all the objects that will receive update events. Only objects on this list have their updateEvent method called by the game loop. I’m trying to implement this method in the GameObject class (This specification is what I’d like the method to achieve): /** * This method removes a GameObject from objectList. The GameObject * should immediately stop executing code, that is, absolutely no more * code inside update events will be executed for the removed game object. * If necessary, control should transfer to the game loop. * @param go The GameObject to be removed */ public void remove(GameObject go) So if an object tries to remove itself inside of an update event, control should transfer back to the game engine: public void updateEvent() { //object's update event remove(this); System.out.println("Should never reach here!"); } Here’s what I have so far. It works, but the more I read about using exceptions for flow control the less I like it, so I want to see if there are alternatives. Remove Method public void remove(GameObject go) { //add to removedList //flag as removed //throw an exception if removing self from inside an updateEvent } Game Loop for(GameObject go : objectList) { try { if (!go.removed) { go.updateEvent(); } else { //object is scheduled to be removed, do nothing } } catch(ObjectRemovedException e) { //control has been transferred back to the game loop //no need to do anything here } } // now remove the objects that are in removedList from objectList 2 questions: Am I correct in assuming that the only way to implement the stop-right-away part of the remove method as described above is by throwing a custom exception and catching it in the game loop? (I know, using exceptions for flow control is like goto, which is bad. I just can’t think of another way to do what I want!) For the removal from the list itself, it is possible for one object to remove one that is farther down on the list. Currently I’m checking a removed flag before executing any code, and at the end of each pass removing the objects to avoid concurrent modification. Is there a better, preferably instant/non-polling way to do this?

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  • C++ Pointer Issue

    - by Winder
    _stuckVertices is an array of pointers and I would like to update one index of that array without using _stuckVertices[ (row * _cols) + column ] 3 times. The reason it is an array of pointers is because the vast majority of the time the pointer will be NULL. The following code works but I need to dereference a each time I use it: void Cloth::stickPoint(int column, int row) { Anchor **a = &_stuckVertices[ (row * _cols) + column ]; if (!*a) *a = new Anchor(this, column, row); (*a)->stick(); } I originally had it written like this, but the _stuckVertices pointer doesn't get updated: void Cloth::stickPoint(int column, int row) { Anchor *a = _stuckVertices[ (row * _cols) + column ]; if (!a) a = new Anchor(this, column, row); a->stick(); } Is there a way to write Anchor *a = _stuckVertices[ index ] so that a is like an alias into the array that I can update, or is something like the first piece of code how I should do this? Thanks

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  • Dropdown binding and postbacks - ASP.NET

    - by DotnetDude
    I have a rather complex page. The ASPX page loads a user control which in turn loads a child User control. Parent Control protected override void OnInit(EventArgs e) { //Loads child control } In the child user control, I use custom control that inherits from System.Web.UI.HtmlControls.HtmlSelect ASCX: <cust:CustDropDownList id="ctlDdl" runat="server"/> ASCX.CS protected void Page_Load(object sender, EventArgs e) { //Binds CtlDdl here } When the user clicks on the Save button, the controls get user controls get dynamically reloaded, but Iose the value the user has selected in the dropdown. I run into the chicken and egg problem here. I think I need to bind the ctlDdl only on if its not a postback, but that results in the dropdown not getting populated. If I bind it everytime, then i lose user's selection EDIT: Can someone respond to my comment to Jonathan's answer? Thanks

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  • Custom Control Events in C#

    - by pm_2
    I'm trying to create a custom control and need to raise an event from it. The idea is to raise an event at the end of the click event (OnAfterClick). I found one or two tutorials on doing this, but am clearly missing a step somewhere; I have the following. In the control: public class AfterClickEventArgs : EventArgs { ... } public partial class MyButton : CommandButton { public delegate void AfterClickEvnt(object sender, AfterClickEventArgs e); public event AfterClickUpdatedEvnt AfterClick; } protected override void OnClick(EventArgs e) { ... Processing here ... AfterClickEventArgs myArgs = new AfterClickEventArgs(); AfterClick(this, newArgs); } In the program using the control: In InitializeComponent(): this.MyButton.AfterClick += new System.EventHandler(this.cmdMyButton_Click); This line is giving me a compile error (cmdMyButton_Click does exist). It tells me: Cannot implicitly convert type 'System.EventHandler' to 'Namespace.MyButton.AfterClick' Can anyone tell me what I'm missing, or misunderstanding about this, please?

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  • iPhone xcode array losing state after load

    - by Frames84
    Right i've had a search around and can't find anything. @synthesize list; // this is an NSArry -(void) viewDidLoad { NSArray *arr = [self getJSONFeed]; self.List = [arr retain]; // if i copy the access code into here it works fine. } -(void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { NSUInteger row = [indexPath row]; NSArray *vals = [list objectAtIndex:row] retain]; NSString *id = [vals valueForKey:@"id"]; // ERROR } right i've taken some of the code to try and provide it as simple as possible, ignore typo's and memory leaks this is sorted. Basically when I select a row I can't get data out of my 'list' array object. Please can anyone help me out?

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  • Delphi 7 WriteProcessMemory

    - by Tprice88
    This is my Working Code DriftMul:=99; WriteProcessMemory(HandleWindow, ptr($4E709C), @DriftMul, 2, Write); I want to Convert it without using a variable but it wont work Below is just an Example of what i want to do. WriteProcessMemory(HandleWindow, ptr($4E709C), ptr(99), 2, Write); Does anyone know a way to make this work with using a variable??? I am able to program in a few languages and every language i use their is a way to to do this. The reason i want to do this is because i am gonna be making a big program that does alot of writing of different values and it will save me around 300+ lines. Below is an Example in c++ i was using. WriteProcessMemory(hProcess, (void*)0x4E709C, (void*)(PBYTE)"\x20", 1, NULL);

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  • Can I use a string variable to reference a class variable?

    - by rson
    Here's the scenario: I have an external swf file with x number of movieclips in its library that I load into a containing swf. Each MC in the external swf is linked with a class name and referenced on frame 1 as such var unique1:lineSequence1 = new lineSequence1(); the unique1 variable name will match a string variable I create in the containing swf: function initLines():void{ lineLoader = new Loader(); lineLoader.load(new URLRequest("theLines.swf")); //load external swf lineLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, linesLoaded); } function linesLoaded(e:Event):void{ var loadedswf:MovieClip = e.target.content as MovieClip; var initialLines = projects[0].pageid; //projects is an xmllist trace("initialLines: "+initialLines); //returns "initialLines: unique1" lines_holder_mc.addChild(loadedswf.[initialLines]); } I would like to use the initialLines variable as the reference to unique1 instead of hardcoding unique1 into loadedswf.unique1 to reference said variable in the loaded swf.

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  • how to create resources without VS C++ 2008 creating MFC files

    - by numerical25
    I am creating a WIN32 application and I want most of all my application events to be made through the message queue. But everytime I create a dialog box or any resource like that. The IDE auto generates code that I don't necessarily need. I believe it's MFC code not sure. here it is. // dlgChangeDevice.cpp : implementation file // #include "stdafx.h" #include "ZFXD3D.h" #include "dlgChangeDevice.h" // dlgChangeDevice dialog IMPLEMENT_DYNAMIC(dlgChangeDevice, CDialog) dlgChangeDevice::dlgChangeDevice(CWnd* pParent /*=NULL*/) : CDialog(dlgChangeDevice::IDD, pParent) { } dlgChangeDevice::~dlgChangeDevice() { } void dlgChangeDevice::DoDataExchange(CDataExchange* pDX) { CDialog::DoDataExchange(pDX); } BEGIN_MESSAGE_MAP(dlgChangeDevice, CDialog) ON_CBN_SELCHANGE(IDC_COMBO5, &dlgChangeDevice::OnCbnSelchangeCombo5) END_MESSAGE_MAP() // dlgChangeDevice message handlers void dlgChangeDevice::OnCbnSelchangeCombo5() { // TODO: Add your control notification handler code here } Not sure what it is but I don't need it. I want to retrieve all my code through the dialog message queue. So what should I do ?? Just disregard it and delete it. Will a hurt anything by doing so ??

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  • Calling class in Java after editing file used in as source for table

    - by user2892290
    I'm currently working on a project, I'll try to subrscibe first. I save data into text file, that I use as a source for browser of that data. The browser is based on table that contains the data. I have to rewrite the source file everytime I delete or edit data. That's where the problem comes in. After deleting or editing data I call a method to create the table again, but the table never creates. Is it possibly made by editing the file and calling the method right after that? If I restart my app the table is successfully created with right data. Take in note that I don't get any error message. This is the method I use for loading data from source file: try (BufferedReader input1 = new BufferedReader(new FileReader("./src/data.src"))) { int lines = 0; while (input1.read() != -1) { if (!(input1.readLine()).equals("")) { lines++; } } input1.close(); if (lines == 0) { JOptionPane.showMessageDialog(null, "No data to load, create a note first!"); new Writer().build(frame); } else { try (BufferedReader input = new BufferedReader(new FileReader("./src/data.src"))) { Game[] g = new Game[lines]; String currentLine; String[] help; int counter = 0; while (lines > 0) { currentLine = input.readLine(); help = currentLine.split("#"); g[counter] = new Game(help[0],help[1], help[2], help[3], help[4], help[5], help[6], help[7], help[8], help[9]); counter++; lines--; } input.close(); final JButton bButton = new backButton().create(frame, mPanel); build(g, frame, bButton); mPanel.add(panel); mPanel.add(panel2); mPanel.add(searchPanel); mPanel.add(bButton); bButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { frame.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR)); panel.removeAll(); frame.setCursor(Cursor.getDefaultCursor()); } }); mPanel.setPreferredSize(new Dimension(1000, 750)); panel.setBorder(new EmptyBorder(10, 10, 10, 10)); frame.setLayout(new FlowLayout()); frame.add(mPanel); frame.pack(); JMenuBar menuBar = new Menu().create(frame, mPanel); frame.setJMenuBar(menuBar); frame.setVisible(true); Rectangle rec = GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds(); int width = (int) rec.getWidth(); int height = (int) rec.getHeight(); frame.setBounds(1, 3, width, height); frame.addComponentListener(new ComponentAdapter() { @Override public void componentMoved(ComponentEvent e) { frame.setLocation(1, 3); } }); And this is the method I use for creating the table: String[][] tableData = new String[g.length][9]; for (int i = 0; i < tableData.length; i++) { tableData[i][0] = g[i].getChampion(); tableData[i][1] = g[i].getRole(); tableData[i][2] = g[i].getEnemy(); tableData[i][3] = g[i].getDifficulty(); tableData[i][4] = g[i].getResult(); tableData[i][5] = g[i].getScore(); tableData[i][6] = g[i].getGameType(); tableData[i][7] = g[i].getPoints(); tableData[i][8] = g[i].getLeague(); } final JLabel searchLabel = new JLabel("Search for champion played."); final JButton searchButton = new JButton("Search"); final JTextField searchText = new JTextField(20); frame.setTitle("LoL Notepad - reading your notes"); JTable table = new JTable(tableData, columnNames); final JScrollPane scrollPane = new JScrollPane(table); scrollPane.setPreferredSize(new Dimension(980, 500)); panel2.setPreferredSize(new Dimension(1000, 550)); panel2.setVisible(false); panel2.setBorder(new EmptyBorder(10, 10, 10, 10)); panel3.setVisible(false); panel.setLayout(new FlowLayout()); panel.add(scrollPane); searchPanel.add(searchLabel); searchPanel.add(searchText); searchPanel.add(searchButton); searchButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { try { frame.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR)); search(g, searchText.getText(), frame, bButton); frame.setCursor(Cursor.getDefaultCursor()); } catch (IOException ex) { Logger.getLogger(Reader.class.getName()).log(Level.SEVERE, null, ex); } } }); table.addMouseListener(new MouseAdapter() { @Override public void mousePressed(MouseEvent e) { if (e.getClickCount() == 1) { JTable target = (JTable) e.getSource(); panel.setVisible(false); searchPanel.setVisible(false); bButton.setVisible(false); int row = target.getSelectedRow(); specific(row, g, frame, bButton); } } });

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  • WCF methods sharing a dictionary

    - by YeomansLeo
    I'm creating a WCF Service Library and I have a question regarding thread-safety consuming a method inside this library, here is the full implementation that I have until now. namespace WCFConfiguration { [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall, ConcurrencyMode = ConcurrencyMode.Single)] public class ConfigurationService : IConfigurationService { ConcurrentDictionary<Tuple<string,string>, string> configurationDictionary = new ConcurrentDictionary<Tuple<string,string>, string>(); public void Configuration(IEnumerable<Configuration> configurationSet) { Tuple<string, string> lookupStrings; foreach (var config in configurationSet) { lookupStrings = new Tuple<string, string>(config.BoxType, config.Size); configurationDictionary.TryAdd(lookupStrings, config.RowNumber); } } public void ScanReceived(string boxType, string size, string packerId = null) { } } } Imagine that I have a 10 values in my configurationDictionary and many people want to query this dictionary consuming ScanReceived method, are those 10 values be shared for each of the clients that request ScanReceived? Do I need to change my ServiceBehavior? The Configuration method is only consumed by one person by the way.

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  • Does template class/function specialization improves compilation/linker speed?

    - by Stormenet
    Suppose the following template class is heavily used in a project with mostly int as typename and linker speed is noticeably slower since the introduction of this class. template <typename T> class MyClass { void Print() { std::cout << m_tValue << std::endl;; } T m_tValue; } Will defining a class specialization benefit compilation speed? eg. void MyClass<int>::Print() { std::cout << m_tValue << std::endl; }

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  • C# 'could not found' existing method

    - by shybovycha
    Greetings! I've been fooling around (a bit) with C# and its assemblies. And so i've found such an interesting feature as dynamic loading assemblies and invoking its class members. A bit of google and here i am, writing some kind of 'assembly explorer'. (i've used some portions of code from here, here and here and none of 'em gave any of expected results). But i've found a small bug: when i tried to invoke class method from assembly i've loaded, application raised MissingMethod exception. I'm sure DLL i'm loading contains class and method i'm tryin' to invoke (my app ensures me as well as RedGate's .NET Reflector): The main application code seems to be okay and i start thinking if i was wrong with my DLL... Ah, and i've put both of projects into one solution, but i don't think it may cause any troubles. And yes, DLL project has 'class library' target while the main application one has 'console applcation' target. So, the question is: what's wrong with 'em? Here are some source code: DLL source: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ClassLibrary1 { public class Class1 { public void Main() { System.Console.WriteLine("Hello, World!"); } } } Main application source: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Reflection; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Assembly asm = Assembly.LoadFrom(@"a\long\long\path\ClassLibrary1.dll"); try { foreach (Type t in asm.GetTypes()) { if (t.IsClass == true && t.FullName.EndsWith(".Class1")) { object obj = Activator.CreateInstance(t); object res = t.InvokeMember("Main", BindingFlags.Default | BindingFlags.InvokeMethod, null, obj, null); // Exception is risen from here } } } catch (Exception e) { System.Console.WriteLine("Error: {0}", e.Message); } System.Console.ReadKey(); } } } UPD: worked for one case - when DLL method takes no arguments: DLL class (also works if method is not static): public class Class1 { public static void Main() { System.Console.WriteLine("Hello, World!"); } } Method invoke code: object res = t.InvokeMember("Main", BindingFlags.Default | BindingFlags.InvokeMethod, null, null, null);

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  • Assigning two strings together getting Access Read Violation

    - by Jay Bell
    I am trying to pass a string to a class mutator and set the private member to that string here is the code that is sending the string void parseTradePairs(Exchange::Currency *curr, std::string *response, int begin, int exit) { int start; int end; string temp; string dataResponse; CURL *tempCurl; initializeCurl(tempCurl); int location = response->find("marketid", begin); if(location <= exit) { start = location + 11; begin = response->find("label", start); end = begin - start - 3; findStrings(start, end, temp, response); getMarketInfo(tempCurl, temp, dataResponse); curr->_coin->setExch(temp); // here is the line of code that is sending the string dataResponse >> *(curr->_coin); curr->_next = new Exchange::Currency(curr, curr->_position + 1); parseTradePairs(curr->_next, response, begin, exit); } } and here is the mutator within the coin class that is receiving the string and assigning it to _exch void Coin::setExch(string exch) { _exch = exch; } I have stepped through it and made sure that exch has the string in it. "105" but soon as it hits _exch = exch; I get the reading violation. I tried passing as pointer as well. I do not believe it should go out of scope. and the string variable in the class is initialized to zero in the default constructor but again that should matter unless I am trying to read from it instead of writing to it. /* defualt constructor */ Coin::Coin() { _id = ""; _label = ""; _code= ""; _name = ""; _marketCoin = ""; _volume = 0; _last = 0; _exch = ""; } Exchange::Exchange(std::string str) { _exch = str; _currencies = new Currency; std::string pair; std::string response; CURL *curl; initializeCurl(curl); getTradePairs(curl, response); int exit = response.find_last_of("marketid"); parseTradePairs(_currencies, &response, 0, exit); } int main(void) { CURL *curl; string str; string id; Coin coin1; initializeCurl(curl); Exchange ex("cryptsy"); curl_easy_cleanup(curl); system("pause"); return 0; } class Exchange { public: typedef struct Currency { Currency(Coin *coin, Currency *next, Currency *prev, int position) : _coin(coin), _next(next), _prev(prev), _position(position) {} Currency(Currency *prev, int position) : _prev(prev), _position(position), _next(NULL), _coin(&Coin()){} Currency() : _next(NULL), _prev(NULL), _position(0) {} Coin *_coin; Currency *_next; Currency *_prev; int _position; }; /* constructor and destructor */ Exchange(); Exchange(std::string str); ~Exchange(); /* Assignment operator */ Exchange& operator =(const Exchange& copyExchange); /* Parse Cryptsy Pairs */ friend void parseTradePairs(Currency *curr, std::string *response, int begin, int exit); private: std::string _exch; Currency *_currencies; }; here is what i changed it to to fix it. typedef struct Currency { Currency(Coin *coin, Currency *next, Currency *prev, int position) : _coin(coin), _next(next), _prev(prev), _position(position) {} Currency(Currency *prev, int position) : _prev(prev), _position(position), _next(NULL), _coin(&Coin()){} Currency() { _next = NULL; _prev = NULL; _position = 0; _coin = new Coin(); } Coin *_coin; Currency *_next; Currency *_prev; int _position; };

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  • How come Java doesn't accept my LinkedList in a Generic, but accepts its own?

    - by master chief
    For a class assignment, we can't use any of the languages bultin types, so I'm stuck with my own list. Anyway, here's the situation: public class CrazyStructure <T extends Comparable<? super T>> { MyLinkedList<MyTree<T>> trees; //error: type parameter MyTree is not within its bound } However: public class CrazyStructure <T extends Comparable<? super T>> { LinkedList<MyTree<T>> trees; } Works. MyTree impleements the Comparable interface, but MyLinkedList doesn't. However, Java's LinkedList doesn't implement it either, according to this. So what's the problem and how do I fix it? MyLinkedList: public class MyLinkedList<T extends Comparable<? super T>> { private class Node<T> { private Node<T> next; private T data; protected Node(); protected Node(final T value); } Node<T> firstNode; public MyLinkedList(); public MyLinkedList(T value); //calls node1.value.compareTo(node2.value) private int compareElements(final Node<T> node1, final Node<T> node2); public void insert(T value); public void remove(T value); } MyTree: public class LeftistTree<T extends Comparable<? super T>> implements Comparable { private class Node<T> { private Node<T> left, right; private T data; private int dist; protected Node(); protected Node(final T value); } private Node<T> root; public LeftistTree(); public LeftistTree(final T value); public Node getRoot(); //calls node1.value.compareTo(node2.value) private int compareElements(final Node node1, final Node node2); private Node<T> merge(Node node1, Node node2); public void insert(final T value); public T extractMin(); public int compareTo(final Object param); }

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  • What is the best design to this class?

    - by HPT
    assume this class: public class Logger { static TextWriter fs = null; public Logger(string path) { fs = File.CreateText(path); } public static void Log(Exception ex) { ///do logging } public static void Log(string text) { ///do logging } } and I have to use this like: Logger log = new Logger(path); and then use Logger.Log() to log what I want. the question is: is this a good design? to instantiate a class and then always call it's static method? any suggestion yield in better design is appreciated.

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  • Validation of method parameters

    - by Anton Tsivarev
    I have a RESTful web service. For implementation using JAX-RS (Jersey). Have the following method: public void foo (@PathParam ("name") String uuid) { ... } I need to do validation of input parameters. And if data invalid throw WebApplicationException. I added my custom annotation CheckUuid (extends ): public void foo (@PathParam ("name") @CheckUuid String uuid) { ... } Is it possible to do validation using annotations on a stage when the method chosen, but not yet called? For example using PreProcessInterceptor?

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  • Purpose of IF, ELSE, FOR macros ?

    - by psihodelia
    I have a source code of a library which has a lot of strange IF, ELSE, FOR, etc. macros for all common C-keywords instead of using just usual if,else,for,while keywords. These macros are defined like this: #define IF( a) if( increment_if(), a) where increment_if() function is defined so: static __inline void increment_if( void) { // If the "IF" operator comes just after an "ELSE", its counter // must not be incremented. ... //implementation } I don't really understand, what is the purpose of such macros? This library is for a real-time application and I suppose that using such macros must slow-down an application.

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  • Query on the scope of local variables in C

    - by darkie15
    All, Consider the following code: void func(void) { int a; printf ("%d", a); } int main(int argc, char **argv) { int a = 3; func(); printf("%d", a); } According to my understanding, the output should be: <junk value><3> Can anyone please confirm my understanding? My basic query is, does the compiler refer to the outer scope for a variable that has been declared but not defined? Regards, darkie

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  • How do I set properties related to the calling method's scope?

    - by Thiado de Arruda
    I'm not looking for a way to associate values with a thread using the 'SetData' method. I need to store some kind of data that will only exist during the scope of a calling method, could be the immediate parent or any other call that is made down on the stack. For example: void SomeMethod() { string someInfo = "someInfo"; SomeOtherMethod(); object data = GetDataOnCurrentScope("someKey"); } void SomeOtherMethod() { SetDataOnParentScope("someKey", somevalue); } In this case both the 'someInfo' local variable and the data set with the "someKey" key will disapear after 'SomeMethod' returns. Is something like this possible? This may go against the rules of a stack, but who knows if someone has an idea...

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  • Object reference case study

    - by Skogen
    When person 1 become partner with person 3, person 2 should no longer have person 1 as partner. How should I solve this? public class Person { private String name; private Person partner; public Person(String name){ this.name = name; } public void setPartner(Person partner){ this.partner = partner; partner.partner = this; } public static void main(String[] args) { Person one = new Person("1"); Person two = new Person("2"); Person three = new Person("3"); Person four = new Person("4"); one.setPartner(two); three.setPartner(four); one.setPartner(three); //Person two is still partner with person 1 }

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  • DBConcurrencyException happening on second delete

    - by Malfist
    My code keeps throwing a DBConcurrencyException ("Concurrency violation: the DeleteCommand affected 0 of the expected 1 records.) when I make a second update to the data table. The problem actually happens on a table that is linked to a parent table. The two tables, CashReceipts and CashReceiptsApplyTo are displayed on the same winform, and when I delete two cash receipts the update on cash receipt apply to's table fails with the dbconcurrencyexception (the table is updated everytime the binding source [linked to a binding navigator] changes position). Here is my code: protected override void saveToDatabase() { tblCashReceiptsBindingSource.EndEdit(); tblCashReceiptsTableAdapter.Update(rentalEaseDataSet.tblCashReceipts); //update the datatable foreach (DataGridViewRow viewRow in viewApplications.Rows) { if (viewRow.Cells[colAppID.Index].Value == null || viewRow.Cells[colApplyTo.Index].Value == null) { continue; } else if ((int)viewRow.Cells[colAppID.Index].Value == -1) { insertNewRow(viewRow); } else { updateRow(viewRow); } } try { tblCashReceiptsApplyToTableAdapter.Update(rentalEaseDataSet.tblCashReceiptsApplyTo); //tblCashReceiptsApplyToTableAdapter.Fill(rentalEaseDataSet.tblCashReceiptsApplyTo); ); } catch (Exception e) { Bitmap bitmap = new Bitmap(this.Width, this.Height); this.DrawToBitmap(bitmap, new Rectangle(0, 0, this.Width, this.Height)); saveScreenshot(this.GetType().FullName, e.Message, bitmap); MessageBox.Show("There was an error saving your changes. This means that you should close the form, and re-enter the last Receipt you entered.\n\nPlease report this."); } } The insertNewRow, and updateRow are simple: private void updateRow(DataGridViewRow viewRow) { //be forgiving if ((int)viewRow.Cells[colAppID.Index].Value == -1) { insertNewRow(viewRow); return; } //find row in table, if it's not there, crash and burn RentalEaseDataSet.tblCashReceiptsApplyToRow updateRow = rentalEaseDataSet.tblCashReceiptsApplyTo.Select("ID = " + viewRow.Cells[colAppID.Index].Value.ToString())[0] as RentalEaseDataSet.tblCashReceiptsApplyToRow; updateRow.BeginEdit(); updateRow.CashReceiptsID = (int)viewRow.Cells[colCashReceipt.Index].Value; updateRow.ApplyTo = (int)viewRow.Cells[colApplyTo.Index].Value; updateRow.Paid = CurrencyToDecimal(viewRow.Cells[colPaid.Index].Value); if (viewRow.Cells[colMemo.Index].Value != null) { updateRow.Memo = viewRow.Cells[colMemo.Index].Value.ToString(); } else { updateRow.SetMemoNull(); } updateRow.EndEdit(); } private void insertNewRow(DataGridViewRow viewRow) { //be forgiving if ((int)viewRow.Cells[colAppID.Index].Value != -1) { updateRow(viewRow); return; } RentalEaseDataSet.tblCashReceiptsApplyToRow newRow = rentalEaseDataSet.tblCashReceiptsApplyTo.NewRow() as RentalEaseDataSet.tblCashReceiptsApplyToRow; newRow.CashReceiptsID = (int) viewRow.Cells[colCashReceipt.Index].Value; newRow.ApplyTo = (int) viewRow.Cells[colApplyTo.Index].Value; newRow.Paid = CurrencyToDecimal(viewRow.Cells[colPaid.Index].Value); if (viewRow.Cells[colMemo.Index].Value != null) { newRow.Memo = viewRow.Cells[colMemo.Index].Value.ToString(); } rentalEaseDataSet.tblCashReceiptsApplyTo.Rows.Add(newRow); //update the ID viewRow.Cells[colAppID.Index].Value = newRow.ID; } Any idea why it would throw that error on the second delete?

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  • Prevent Erroneous Property Assignment

    - by Gordon
    Porting android applications to iphone applications always gives me the following pattern that I accidentally create: - (void) myFunc:(id)prop { self.property = property; } Which instead should be: - (void) myFunc:(id)prop { self.property = prop; } This always causes my program to quietly break because property gets reset to its existing value rather than being set to the new value, 'prop'. I cannot name the parameter 'prop' to 'property' since the compile complains that the parameter masks the instance variables visibility. Is there a good way to avoid this situation? There are no compiler warnings. Is there a way to make xcode prevent this? I cannot see very many situations where you would set a property to the value of its underlying instance variable (maybe to trigger a KVO binding?), but I don't see myself doing that in majority of cases. I understand the above code is synthetic and should be done with @synthesize, but I am just using it as a simplified example to illustrate my point.

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