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  • Need advice on C++ coding pattern

    - by Kotti
    Hi! I have a working prototype of a game engine and right now I'm doing some refactoring. What I'm asking for is your opinion on usage of the following C++ coding patterns. I have implemented some trivial algorithms for collision detection and they are implemented the following way: Not shown here - class constructor is made private and using algorithms looks like Algorithm::HandleInnerCollision(...) struct Algorithm { // Private routines static bool is_inside(Point& p, Object& object) { // (...) } public: /** * Handle collision where the moving object should be always * located inside the static object * * @param MovingObject & mobject * @param const StaticObject & sobject * @return void * @see */ static void HandleInnerCollision(MovingObject& mobject, const StaticObject& sobject) { // (...) } So, my question is - somebody advised me to do it "the C++" way - so that all functions are wrapped in a namespace, but not in a class. Is there some good way to preserve privating if I will wrap them into a namespace as adviced? What I want to have is a simple interface and ability to call functions as Algorithm::HandleInnerCollision(...) while not polluting the namespace with other functions such as is_inside(...) Of, if you can advise any alternative design pattern for such kind of logics, I would really appreciate that...

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  • How to mix Grammer (Rules) & Dictation (Free speech) with SpeechRecognizer in C#

    - by Lee Englestone
    I really like Microsofts latest speech recognition (and SpeechSynthesis) offerings. http://msdn.microsoft.com/en-us/library/ms554855.aspx http://estellasays.blogspot.com/2009/04/speech-recognition-in-cnet.html However I feel like I'm somewhat limited when using grammers. Don't get me wrong grammers are great for telling the speech recognition exactly what words / phrases to look out for, however what if I want it to recognise something i've not given it a heads up about? Or I want to parse a phrase which is half pre-determined command name and half random words? For example.. Scenario A - I say "Google [Oil Spill]" and I want it to open Google with search results for the term in brackets which could be anything. Scenario B - I say "Locate [Manchester]" and I want it to search for Manchester in Google Maps or anything else non pre-determined I want it to know that 'Google' and 'Locate' are commands and what comes after it are parameters (and could be anything). Question : Does anyone know how to mix the use of pre-determined grammers (words the speech recognition should recognise) and words not in its pre-determined grammer? Code fragments.. using System.Speech.Recognition; ... ... SpeechRecognizer rec = new SpeechRecognizer(); rec.SpeechRecognized += rec_SpeechRecognized; var c = new Choices(); c.Add("search"); var gb = new GrammarBuilder(c); var g = new Grammar(gb); rec.LoadGrammar(g); rec.Enabled = true; ... ... void rec_SpeechRecognized(object sender, SpeechRecognizedEventArgs e) { if (e.Result.Text == "search") { string query = "How can I get a word not defined in Grammer recognised and passed into here!"; launchGoogle(query); } } ... ... private void launchGoogle(string term) { Process.Start("IEXPLORE", "google.com?q=" + term); }

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  • DCI: How to implement Context with Dependency Injection?

    - by ciscoheat
    Most examples of a DCI Context are implemented as a Command pattern. When using Dependency Injection though, it's useful to have the dependencies injected in the constructor and send the parameters into the executing method. Compare the Command pattern class: public class SomeContext { private readonly SomeRole _someRole; private readonly IRepository<User> _userRepository; // Everything goes into the constructor for a true encapsuled command. public SomeContext(SomeRole someRole, IRepository<User> userRepository) { _someRole = someRole; _userRepository = userRepository; } public void Execute() { _someRole.DoStuff(_userRepository); } } With the Dependency injected class: public class SomeContext { private readonly IRepository<User> _userRepository; // Only what can be injected using the DI provider. public SomeContext(IRepository<User> userRepository) { _userRepository = userRepository; } // Parameters from the executing method public void Execute(SomeRole someRole) { someRole.DoStuff(_userRepository); } } The last one seems a bit nicer, but I've never seen it implemented like this so I'm curious if there are any things to consider.

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  • Infile incomplete type error

    - by kd7vdb
    I am building a program that takes a input file in this format: title author title author etc and outputs to screen title (author) title (author) etc The Problem I am currently getting is a error "ifstream infile has incomplee type and cannot be defined" #include <iostream> #include <string> #include <ifstream> using namespace std; string bookTitle [14]; string bookAuthor [14]; int loadData (string pathname); void showall (int counter); int main () { int counter; string pathname; cout<<"Input the name of the file to be accessed: "; cin>>pathname; loadData (pathname); showall (counter); } int loadData (string pathname) // Loads data from infile into arrays { ifstream infile; int counter = 0; infile.open(pathname); //Opens file from user input in main if( infile.fail() ) { cout << "File failed to open"; return 0; } while (!infile.eof()) { infile >> bookTitle [14]; //takes input and puts into parallel arrays infile >> bookAuthor [14]; counter++; } infile.close; } void showall (int counter) // shows input in title(author) format { cout<<bookTitle<<"("<<bookAuthor<<")"; } Thanks ahead of time, kd7vdb

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  • Using an empty column as a divider in a JTable.

    - by Catalina Island
    I'm trying to use an empty column as a divider between pairs of columns in a JTable. Here's a picture and code for what I have so far. I know I can change the look using a custom TableCellRenderer. Before I go down that road, is there a better way to do this? Any ideas appreciated. import javax.swing.*; import javax.swing.table.*; public class TablePanel extends JPanel { public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { JFrame f = new JFrame("TablePanel"); f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); f.add(new TablePanel()); f.pack(); f.setVisible(true); } }); } public TablePanel() { TableModel dataModel = new MyModel(); JTable table = new JTable(dataModel); table.getColumnModel().getColumn(MyModel.DIVIDER).setMaxWidth(0); JScrollPane jsp = new JScrollPane(table); jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); this.add(jsp); } private static class MyModel extends AbstractTableModel { private static final int DIVIDER = 2; private final String[] names = { "A1", "A2", "", "B1", "B2" }; @Override public int getRowCount() { return 32; } @Override public int getColumnCount() { return names.length; } @Override public String getColumnName(int col) { if (col == DIVIDER) return ""; return names[col]; } @Override public Object getValueAt(int row, int col) { if (col == DIVIDER) return ""; return (row + 1) / 10.0; } @Override public Class<?> getColumnClass(int col) { if (col == DIVIDER) return String.class; return Number.class; } } }

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  • Android AutocompleteView OnClickListener

    - by Chirag_RB
    I have 2 Auto Complete Views which i have to pre-populate with some text .However as soon as user clicks on the views , the text should disappear and allow user to enter text . I have written two separate on click listeners to do so . The On click listener for the first one is working fine . However i have to double click for the On click listener of the second one to work. Please find the chunk of code below and come up with some solution . final AutoCompleteTextView source = (AutoCompleteTextView) findViewById(R.id.source); ArrayAdapter source_adapter = new ArrayAdapter(this, R.layout.list_item, Model.City); source.setAdapter(source_adapter); source.setOnClickListener(new OnClickListener(){ public void onClick(View v) { source.setText(""); source.setTextSize(14); } }); final AutoCompleteTextView destination = (AutoCompleteTextView) findViewById(R.id.destination); ArrayAdapter destination_adapter = new ArrayAdapter(this, R.layout.list_item, Model.City); destination.setAdapter(destination_adapter); destination.setOnClickListener(new OnClickListener(){ public void onClick(View v) { destination.setText(""); destination.setTextSize(14); } });

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  • better understanding of getline() and cin

    - by numerical25
    Trying to get some basic understanding of console functionalities. I am having issues so consider the following... #include "stdafx.h" #include<iostream> #include<conio.h> using namespace std; /* This is a template Project */ void MultiplicationTable(int x); int main() { int value = 0; printf("Please enter any number \n\n"); getline(cin, value); MultiplicationTable(value); getchar(); return 0; } I actually based this off code from http://www.cplusplus.com/doc/tutorial/basic_io/ . My IDE is not recognizing getline() so of course when I compile the application. I get an error 'getline': identifier not found Now take a look at this code #include "stdafx.h" #include<iostream> #include<conio.h> using namespace std; /* This is a template Project */ void MultiplicationTable(int x); int main() { int value = 0; printf("Please enter any number \n\n"); cin>>value; MultiplicationTable(value); getchar(); return 0; } When I execute this line of code the console window opens and immediately closes. I think I a missing something about cin. I do know that it delimits spaces but I don't know what else. what should I use for input to make my life easier.

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  • Java constructor using generic types

    - by user37903
    I'm having a hard time wrapping my head around Java generic types. Here's a simple piece of code that in my mind should work, but I'm obviously doing something wrong. Eclipse reports this error in BreweryList.java: The method initBreweryFromObject() is undefined for the type <T> The idea is to fill a Vector with instances of objects that are a subclass of the Brewery class, so the invocation would be something like: BreweryList breweryList = new BreweryList(BrewerySubClass.class, list); BreweryList.java package com.beerme.test; import java.util.Vector; public class BreweryList<T extends Brewery> extends Vector<T> { public BreweryList(Class<T> c, Object[] j) { super(); for (int i = 0; i < j.length; i++) { T item = c.newInstance(); // initBreweryFromObject() is an instance method // of Brewery, of which <T> is a subclass (right?) c.initBreweryFromObject(); // "The method initBreweryFromObject() is undefined // for the type <T>" } } } Brewery.java package com.beerme.test; public class Brewery { public Brewery() { super(); } protected void breweryMethod() { } } BrewerySubClass.java package com.beerme.test; public class BrewerySubClass extends Brewery { public BrewerySubClass() { super(); } public void androidMethod() { } } I'm sure this is a complete-generics-noob question, but I'm stuck. Thanks for any tips!

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  • What is wrong with this Asynchronus task?

    - by bluebrain
    the method onPostExecute simply was not executed, I have seen 16 at LogCat but I can not see 16 in LogCAT. I tried to debug it, it seemed that it goes to the first line of the class (package line) after return statement. private class Client extends AsyncTask<Integer, Void, Integer> { protected Integer doInBackground(Integer... params) { Log.e(TAG,10+""); try { socket = new Socket(target, port); Log.e(TAG,11+""); oos = new ObjectOutputStream(socket.getOutputStream()); Log.e(TAG,14+""); ois = new ObjectInputStream(socket.getInputStream()); Log.e(TAG,15+""); } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } Log.e(TAG,16+""); return 1; } protected void onPostExecute(Integer result) { Log.e(TAG,13+""); try { Log.e(TAG,12+""); oos.writeUTF(key); Log.e(TAG,13+""); if (ois.readInt() == OKAY) { isConnected = true; Log.e(TAG,14+""); }else{ Log.e(TAG,15+""); isConnected = false; } } catch (IOException e) { e.printStackTrace(); isClosed = true; } } }

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  • A Null Reference Exception

    - by Alex
    "Object reference not set to an instance of an object." using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.Graphics; namespace XNAdev { class Sprite { //The size of the Sprite public Rectangle Size; //Used to size the Sprite up or down from the original image public float Scale = 1.0f; //The current position of the Sprite public Vector2 Position = new Vector2(115, 0); //The texture object used when drawing the sprite private Texture2D mSpriteTexture; //Load the texture for the sprite using the Content Pipeline public void LoadContent(ContentManager theContentManager, string theAssetName) { mSpriteTexture = theContentManager.Load<Texture2D>(theAssetName); Size = new Rectangle(0, 0, (int)(mSpriteTexture.Width * Scale), (int)(mSpriteTexture.Height * Scale)); } //Draw the sprite to the screen public void Draw(SpriteBatch theSpriteBatch) { theSpriteBatch.Draw(mSpriteTexture, Position, new Rectangle(0, 0, mSpriteTexture.Width, mSpriteTexture.Height), Color.White, 0.0f, Vector2.Zero, Scale, SpriteEffects.None, 0); } } } I am very new at this C# so any help would be great. I have no idea what my error is.

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  • C# object (2 numbers) performing 2 calculations

    - by Chris
    I have a couple questions about creating a object (2 values) and how to "call" it. Initializing the object with: Tweetal t1, t2, t3, t4, t5, t6; t1 = new Tweetal(); //a: 0 , b = 0 t2 = new Tweetal(-2); //a: -2, b = -2 t3 = new Tweetal(5, 17); //a: 5, b = 17 t4 = new Tweetal(t3); //a:5, b = 17 Console.Write("t1 = " + t1); Console.Write("\tt2 = " + t2); Console.Write("\tt3 = " + t3); Console.Write("\tt4 = " + t4); Console.WriteLine("\n"); t1 = t1.Som(t2); t4 = t2.Som(t2); //...... Now the 2 things i want to do with this object are taking the SUM and the SUMNumber: Sum: t4 = t2.sum(t3); (this would result in t4: a:3 (-2+5), b: 15(-2+17) SumNumber: t1 = t3.sum(8) (this would result in t1: a:13 , b:25) Next is my code for the object (in a separate class), but how exactly do i perform the simple sum calculation when i call up for example t2 etc... public class Tweetal: Object { private int a; private int b; public Tweetal() { //??? //Sum(...,...) } public Tweetal(int a) { //??? //Sum(...,...) } public Tweetal(int a, int b) { //??? } public Tweetal(Tweetal //....) // to call upton the object if i request t1, t2, t3,... insteed of a direct number value) { // ???? } public void Sum(int aValue, int bValue) { //a = ??? //b = ??? //Sum(...,...) } public void SumNumber(int aValue, int bValue) { } public override string ToString() { return string.Format("({0}, {1})", a, b); }/*ToString*/ }

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  • Unexpected behaviour of Process.MainWindowHandle

    - by Ed Guiness
    I've been trying to understand Process.MainWindowHandle. According to MSDN; "The main window is the window that is created when the process is started. After initialization, other windows may be opened, including the Modal and TopLevel windows, but the first window associated with the process remains the main window." (Emphasis added) But while debugging I noticed that MainWindowHandle seemed to change value... which I wasn't expecting, especially after consulting the documentation above. To confirm the behaviour I created a standalone WinForms app with a timer to check the MainWindowHandle of the "DEVENV" (Visual Studio) process every 100ms. Here's the interesting part of this test app... IntPtr oldHWnd = IntPtr.Zero; void GetMainwindowHandle() { Process[] processes = Process.GetProcessesByName("DEVENV"); if (processes.Length!=1) return; IntPtr newHWnd = processes[0].MainWindowHandle; if (newHWnd != oldHWnd) { oldHWnd = newHWnd; textBox1.AppendText(processes[0].MainWindowHandle.ToString("X")+"\r\n"); } } private void timer1Tick(object sender, EventArgs e) { GetMainwindowHandle(); } You can see the value of MainWindowHandle changing when you (for example) click on a drop-down menu inside VS. Perhaps I've misunderstood the documentation. Can anyone shed light?

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  • How do I pass references as method parameters across AppDomains?

    - by Thiado de Arruda
    I have been trying to get the following code to work(everything is defined in the same assembly) : namespace SomeApp{ public class A : MarshalByRefObject { public byte[] GetSomeData() { // } } public class B : MarshalByRefObject { private A remoteObj; public void SetA(A remoteObj) { this.remoteObj = remoteObj; } } public class C { A someA = new A(); public void Init() { AppDomain domain = AppDomain.CreateDomain("ChildDomain"); string currentAssemblyPath = Assembly.GetExecutingAssembly().Location; B remoteB = domain.domain.CreateInstanceFromAndUnwrap(currentAssemblyPath,"SomeApp.B") as B; remoteB.SetA(someA); // this throws an ArgumentException "Object type cannot be converted to target type." } } } What I'm trying to do is pass a reference of an 'A' instance created in the first AppDomain to the child domain and have the child domain execute a method on the first domain. In some point on 'B' code I'm going to call 'remoteObj.GetSomeData()'. This has to be done because the 'byte[]' from 'GetSomeData' method must be 'calculated' on the first appdomain. What should I do to avoid the exception, or what can I do to achieve the same result?

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  • Method invoked but not returning anything

    - by or azran
    i am calling this method from a touch in UITableViewCell , -(void)PassTitleandiMageByindex:(NSString *)number{ NSLog(@"index : %d",number.intValue); NSArray *objectsinDictionary = [[[NSArray alloc]init]autorelease]; objectsinDictionary = [[DataManeger sharedInstance].sortedArray objectAtIndex:number.intValue]; if ([objectsinDictionary count] > 3) { ProductLabel = [objectsinDictionary objectAtIndex:3]; globaliMageRef = [objectsinDictionary objectAtIndex:2]; [self performSegueWithIdentifier:@"infoseg" sender:self]; }else{ mQid = [objectsinDictionary objectAtIndex:1]; globaliMageRef = [objectsinDictionary objectAtIndex:2]; [mIQEngines Result:mQid]; NSLog(@"mQid : %@ Global : %@",mQid,globaliMageRef); }} Problem:- i am trying to get the same functionality programmatically by calling [self PassTitleandiMageByindex:stringNumber]; when i am calling this programmatically i can see the debug log getting in the place it should be, but nothing happens (by pressing the UITableViewCellon the screen) here is how it turns on by touch, - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{ [tableView deselectRowAtIndexPath:indexPath animated:YES]; NSString *st = [NSString stringWithFormat:@"%d",[indexPath row]]; [self PassTitleandiMageByindex:st];} I have also tried to call the table-view delegate by :[[Tview delegate] tableView:Tview didSelectRowAtIndexPath:selectedCellIndexPath]; but, nothing happened.

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  • Interpreting item click in ListView

    - by Matt Huggins
    I'm working on my first Android project, and I created a menu via the XML method. My activity is pretty basic, in that it loads the main layout (containing a ListView with my String array of options). Here's the code inside my Activity: public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // allow stuff to happen when a list item is clicked ListView ls = (ListView)findViewById(R.id.menu); ls.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // @todo } }); } Within the onItemClick callback handler, I'd like to check which item was clicked, and load a new menu based upon that. Question 1: How do I go about figuring out which item was clicked? I can't find any straightforward examples on retrieving/testing the id value of the clicked item. Question 2: Once I have the id value, I assume I can just call the setContentView method again to change to another layout containing my new menu. Is that correct?

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  • Moving Computer Player in Xcode

    - by user1631497
    I am working on a 2d game using xcode and objective-c. I am trying to make my enemy player move left if I am left of him, until he is touching my character. The same will go when I am right of him. Basically just trying to get him to move towards me. But my code to do so is not working. So I have my code that says the following -(void)moveTowardsCharacter { enemyLeftTimer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(goEnemyLeft) userInfo:nil repeats:YES]; if (enemyLeftTimer == nil){ enemyLeftTimer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(goEnemyLeft) userInfo:nil repeats:YES]; } } -(IBAction)enemyStopLeft { if (CGRectIntersectsRect(bluebox.frame, redbox.frame)) { [enemyLeftTimer invalidate]; enemyLeftTimer = nil; } } -(void)goEnemyLeft { if (redbox.center.x + [self getRedboxWidthLeft] > bluebox.center.x + [self getBlueboxWidthRight]) { redbox.center = CGPointMake(redbox.center.x -5, redbox.center.y); } } So the first bit is saying for it to set up a timer to continue moving left. The next will stop the timer if my player(bluebox) and the Computer player(redbox) collide. Finally, the thing that actually tells it to go left, but only if the bluebox is left of the redbox. The getRedBoxWidth Left and getBlueBoxWidthRight are just voids that get, well, the left and right edges. If you could, please help try and solve this code. Thank You.

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  • Optimization of a c++ matrix/bitmap class

    - by Andrew
    I am searching a 2D matrix (or bitmap) class which is flexible but also fast element access. The contents A flexible class should allow you to choose dimensions during runtime, and would look something like this (simplified): class Matrix { public: Matrix(int w, int h) : data(new int[x*y]), width(w) {} void SetElement(int x, int y, int val) { data[x+y*width] = val; } // ... private: // symbols int width; int* data; }; A faster often proposed solution using templates is (simplified): template <int W, int H> class TMatrix { TMatrix() data(new int[W*H]) {} void SetElement(int x, int y, int val) { data[x+y*W] = val; } private: int* data; }; This is faster as the width can be "inlined" in the code. The first solution does not do this. However this is not very flexible anymore, as you can't change the size anymore at runtime. So my question is: Is there a possibility to tell the compiler to generate faster code (like when using the template solution), when the size in the code is fixed and generate flexible code when its runtime dependend? I tried to achieve this by writing "const" where ever possible. I tried it with gcc and VS2005, but no success. This kind of optimization would be useful for many other similar cases.

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  • Error emailing outgoing sms

    - by BirthOfTragedy
    Is there anyway to listen for an outbound sms without having to import javax.wireless.messaging? I'm trying to write an app that listens for an sms sent from the device then emails the message of the sms, but I get the error: reference to Message is ambiguous, both class javax.wireless.messaging.Message in javax.wireless.messaging and class net.rim.blackberry.api.mail.Message in net.rim.blackberry.api.mail match I need to import net.rim.blackberry.api.mail.Message in order to sent an email. Is there a way to get around this as it seems that the two packages are clashing. My code: public void notifyIncomingMessage(MessageConnection messageconnection) {} public void notifyOutgoingMessage(javax.wireless.messaging.Message message) { try { String address = message.getAddress(); String msg = null; if ( message instanceof TextMessage ) { TextMessage tm = (TextMessage)message; msg = tm.getPayloadText(); } else if (message instanceof BinaryMessage) { StringBuffer buf = new StringBuffer(); byte[] data = ((BinaryMessage) message).getPayloadData(); msg = new String(data, "UTF-8"); Store store = Session.getDefaultInstance().getStore(); Folder[] folders = store.list(Folder.SENT); Folder sentfolder = folders[0]; Message in = new Message(sentfolder); Address recipients[] = new Address[1]; recipients[0]= new Address("[email protected]", "user"); in.addRecipients(Message.RecipientType.TO, recipients); in.setSubject("Outgoing sms"); in.setContent("You have just sent an sms to: " + address + "\n" + "Message: " + msg); in.setPriority(Message.Priority.HIGH); Transport.send(in); in.setFlag(Message.Flag.OPENED, true); Folder folder = in.getFolder(); folder.deleteMessage(in); } } catch (IOException me) { System.out.println(me); } } }

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  • Using abstract base to implement private parts of a template class?

    - by StackedCrooked
    When using templates to implement mix-ins (as an alternative to multiple inheritance) there is the problem that all code must be in the header file. I'm thinking of using an abstract base class to get around that problem. Here's a code sample: class Widget { public: virtual ~Widget() {} }; // Abstract base class allows to put code in .cpp file. class AbstractDrawable { public: virtual ~AbstractDrawable() = 0; virtual void draw(); virtual int getMinimumSize() const; }; // Drawable mix-in template<class T> class Drawable : public T, public AbstractDrawable { public: virtual ~Drawable() {} virtual void draw() { AbstractDrawable::draw(); } virtual int getMinimumSize() const { return AbstractDrawable::getMinimumSize(); } }; class Image : public Drawable< Widget > { }; int main() { Image i; i.draw(); return 0; } Has anyone walked that road before? Are there any pitfalls that I should be aware of?

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  • Is it OK to set state within Event Raising methods?

    - by Greg
    I ran across this pattern in the code of a library I'm using. It sets state within the event raising method, but only if the event is not null. protected virtual void OnMyEvent(EventArgs e) { if(MyEvent != null) { State = "Executing"; // Only sets state if MyEvent != null. MyEvent(this,e); } } Which means that the state is not set when overriding the method: protected override void OnMyEvent(EventArgs e) { base.OnMyEvent(e); Debug.Assert( State == "Executing" ); // This fails } but is only set when handling the event: foo.MyEvent += (o, args) => Debug.Assert(State == "Executing"); // This passes Setting state within the if(MyEvent != null) seems like bad form, but I've checked the Event Design Guidelines and it doesn't mention this. Do you think this code is incorrect? If so, why? (Reference to design guidelines would be helpful). Edit for Context: It's a Control, I'm trying to create subclass of it, and the state that it's setting is calling EnsureChildControls() conditionally based upon there being an event handler. I can call EnsureChildControls() myself, but I consider that something of a hack.

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  • Using a single texture image unit with multiple sampler uniforms

    - by bcrist
    I am writing a batching system which tracks currently bound textures in order to avoid unnecessary glBindTexture() calls. I'm not sure if I need to keep track of which textures have already been used by a particular batch so that if a texture is used twice, it will be bound to a different TIU for the second sampler which requires it. Is it acceptable for an OpenGL application to use the same texture image unit for multiple samplers within the same shader stage? What about samplers in different shader stages? For example: Fragment shader: ... uniform sampler2D samp1; uniform sampler2D samp2; void main() { ... } Main program: ... glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, tex_id); glUniform1i(samp1_location, 0); glUniform1i(samp2_location, 0); ... I don't see any reason why this shouldn't work, but what about if the shader program also included a vertex shader like this: Vertex shader: ... uniform sampler2D samp1; void main() { ... } In this case, OpenGL is supposed to treat both instances of samp1 as the same variable, and exposes a single location for them. Therefore, the same texture unit is being used in the vertex and fragment shaders. I have read that using the same texture in two different shader stages counts doubly against GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS but this would seem to contradict that. In a quick test on my hardware (HD 6870), all of the following scenarios worked as expected: 1 TIU used for 2 sampler uniforms in same shader stage 1 TIU used for 1 sampler uniform which is used in 2 shader stages 1 TIU used for 2 sampler uniforms, each occurring in a different stage. However, I don't know if this is behavior that I should expect on all hardware/drivers, or if there are performance implications.

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  • User Defined Conversions in C++

    - by wash
    Recently, I was browsing through my copy of the C++ Pocket Reference from O'Reilly Media, and I was surprised when I came across a brief section and example regarding user-defined conversion for user-defined types: #include <iostream> class account { private: double balance; public: account (double b) { balance = b; } operator double (void) { return balance; } }; int main (void) { account acc(100.0); double balance = acc; std::cout << balance << std::endl; return 0; } I've been programming in C++ for awhile, and this is the first time I've ever seen this sort of operator overloading. The book's description of this subject is somewhat brief, leaving me with a few unanswered questions about this feature: Is this a particularly obscure feature? As I said, I've been programming in C++ for awhile and this is the first time I've ever come across this. I haven't had much luck finding more in-depth material regarding this. Is this relatively portable? (I'm compiling on GCC 4.1) Can user-defined conversions to user defined types be done? e.g. operator std::string () { /* code */ }

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  • std::bad_cast from parent to child?

    - by polyglot
    For simplicity, class Parent {} class Child1 : Parent {} class Child2 : Parent {} Elsewhere, I created instances of Child1 and Child2 and store it in same vector under Parent: // . . . in .h file, for example vector<Parent> vector_of_parent; // . . . in one particular method Child1 c1(); Child2 c2(); vector_of_parent.push_back(c1); vector_of_parent.push_back(c2); // . . . Then in another method which has access to vector_of_parent, I tried void doSomething(Parent& some_child) { // wrapped in a try block somehow... Child1& c = dynamic_cast<Child1&> some_child; // do something if the cast is successful } void otherMethod() { doSomething(vector_of_parent.at(0)); // vector_of_parent.at(0) is a Child1 } Why is there a std:bad_cast when I call otherMethod()?

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  • How can I create an instance of a class that I can use is more than one place in c#

    - by user1743574
    So I've been working on a class that details students of a university. I have one button that sets the details to a new instance of a class, and another to check if the student passed, through a method in my Class. The problem is that I create an instance of a class in the first button to add the values from what the user input, but I cannot use the second button to access the instance of the class created in the first button. private void button3_Click(object sender, EventArgs e) { Student student1 = new Student(); label1.Text = student1.text(); if (student1.hasPassed() == true) { passfailtextbox.Text = "Pass"; } else { passfailtextbox.Text = "Fail"; } } private void button1_Click(object sender, EventArgs e) { Student student1 = new Student(); student1.FirstName = firstnamebox.Text; student1.SecondName = secondnamebox.Text; student1.DateofBirth = DateTime.Parse(dobtextbox.Text).Date; student1.Course = coursetextbox.Text; student1.MatriculationNumber = int.Parse(matriculationtextbox.Text); student1.YearMark = double.Parse(yearmarktextbox.Text); } public Boolean hasPassed() { if (YearMark < 40) { return false; } else { return true; } } public string text() { return "Student" + " " + firstname + " " + secondname + " " + course + " " + dob.ToString() + " " + matriculationnumber.ToString() + " " + yearmark.ToString() ; }

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  • OnClickListener cannot be resolved to a type

    - by Webnet
    I'm diving into Java (this is day 1) and I'm trying to create a button that will trigger a notification when I click it... This code is based off of the notification documentation here, and UI events documentation here package com.example.contactwidget; import android.app.Activity; import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.widget.Button; public class ContactWidget extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Button calc1 = (Button) findViewById(R.id.calc_button_1); calc1.setOnClickListener(buttonListener); setContentView(R.layout.main); } private static final int HELLO_ID = 1; //Error: OnClickListener cannot be resolved to a type private OnClickListener buttonListener = new OnClickListener() { public void onClick (View v) { String ns = Context.NOTIFICATION_SERVICE; NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns); int icon = R.drawable.icon; CharSequence ticketBrief = "Button Pressed Brief"; CharSequence ticketTitle = "Button pressed"; CharSequence ticketText = "You pressed button 1"; long when = System.currentTimeMillis(); Notification notification = new Notification(icon, ticketBrief, when); Intent notificationIntent = new Intent(this, ContactWidget.class); PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0); notification.setLatestEventInfo(getApplicationContext(), ticketTitle, ticketText, contentIntent); mNotificationManager.notify(HELLO_ID, notification); } } } I'm running into a problem: OnClickListener cannot be resolved to a type. The problem here is that I don't see any problems with my code in relation to the example I'm using

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