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  • Ladder word-like game GUI problems

    - by sasquatch90
    Ok so I've written my own version of game which should look like this : http://img199.imageshack.us/img199/6859/lab9a.jpg but mine looks like that : http://img444.imageshack.us/img444/7671/98921674.jpg How can I fix this ? Is there a way to do the layout completely differently ? Here's the code : Main.java : import java.util.Scanner; import javax.swing.*; import java.awt.*; public class Main { public static void main(String[] args){ final JFrame f = new JFrame("Ladder Game"); Scanner sc = new Scanner(System.in); System.out.println("Creating game data..."); System.out.println("Height: "); while (!sc.hasNextInt()) { System.out.println("int, please!"); sc.next(); } final int height = sc.nextInt(); Grid[]game = new Grid[height]; for(int L = 0; L < height; L++){ Grid row = null; int i = L+1; String s; do { System.out.println("Length "+i+", please!"); s = sc.next(); } while (s.length() != i); Element[] line = new Element[s.length()]; Element single = null; String[] temp = null; String[] temp2 = new String[s.length()]; temp = s.split(""); for( int j = temp2.length; j>0; j--){ temp2[j-1] = temp[j]; } for (int k = 0 ; k < temp2.length ; k++) { if( k == 0 ){ single = new Element(temp2[k], 2); } else{ single = new Element(temp2[k], 1); } line[k] = single; } row = new Grid(line); game[L] = row; } //############################################ //THE GAME STARTS HERE //############################################ JPanel panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS)); panel.setBackground(Color.ORANGE); panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); for(int i = 0; i < game.length; i++){ panel.add(game[i].create()); } f.setContentPane(panel); f.pack(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true); boolean end = false; boolean word = false; String tekst; while( !end ){ while( !word ){ tekst = JOptionPane.showInputDialog("Input word: "); for(int i = 0; i< game.length; i++){ if(game[i].equalLength(tekst)){ if(game[i].equalValue(tekst)){ word = true; for(int j = 0; j< game.length; j++){ game[i].repaint(); } } } } } word = false; for(int i = 0; i < game.length; i++){ if(game[i].solved()){ end = true; } else { end = false; } } } } } Grid.java import javax.swing.*; import java.awt.*; public class Grid extends JPanel{ private Element[]e; private Grid[]g; public Grid(){} public Grid( Element[]elements ){ e = new Element[elements.length]; for(int i=0; i< e.length; i++){ e[i] = elements[i]; } } public Grid(Grid[]grid){ g = new Grid[grid.length]; for(int i=0; i<g.length; i++){ g[i] = grid[i]; } Dimension d = new Dimension(600, 600); setMinimumSize(d); setPreferredSize(new Dimension(d)); setMaximumSize(d); } public JPanel create(){ JPanel panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS)); panel.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2)); for(int j = 0; j < e.length; j++){ panel.add(e[j].paint()); } return panel; } @Override public void repaint(){ } public boolean equalLength(String s){ int len = s.length(); boolean equal = false; for(int j = 0; j < e.length; j++){ if(e.length == len){ equal = true; } } return equal; } public boolean equalValue(String s){ int len = s.length(); boolean equal = false; String[] temp = null; String[] temp2 = new String[len]; temp = s.split(""); for( int j = len; j>0; j--){ temp2[j-1] = temp[j]; } for(int j = 0; j < e.length; j++){ if( e[j].letter().equals(temp2[j]) ){ equal = true; } else { equal = false; } } if(equal){ for(int i = 0; i < e.length; i++){ e[i].changeState(3); } } return equal; } public boolean solved(){ boolean solved = false; for(int j = 0; j < e.length; j++){ if(e[j].getState() == 3){ solved = true; } else { solved = false; } } return solved; } @Override public String toString(){ return ""; } } Element.java import javax.swing.*; import java.awt.*; public class Element { final int INVISIBLE = 0; final int EMPTY = 1; final int FIRST_LETTER = 2; final int OTHER_LETTER = 3; private int state; private String letter; public Element(){ } //empty block public Element(int state){ this("", 0); } //filled block public Element(String s, int state){ this.state = state; this.letter = s; } public JButton paint(){ JButton button = null; if( state == EMPTY ){ button = new JButton(""); button.setBackground(Color.WHITE); } else if ( state == FIRST_LETTER ){ button = new JButton(letter); button.setBackground(Color.red); } else { button = new JButton(letter); button.setBackground(Color.yellow); } button.setSize(20,20); return button; } public void changeState(int s){ state = s; } public String letter(){ return letter; } public int getState(){ return state; } @Override public String toString(){ return "["+letter+"]"; } }

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  • What does it mean to pass a &variable to a function? E.g., string& insert ( size_t pos1, const strin

    - by Bob Montgomery
    I understand passing a pointer, and returning a pointer: char * strcat ( char * destination, const char * source ); You're passing a variable that contains the address to a char; returning the same. But what does it mean to pass something using the reference operator? Or to return it? string& insert ( size_t pos1, const string& str ); I mean, I understand what actually happens, I just don't understand the notation. Why isn't the notation this instead: string * insert ( size_t pos1, const string * str ); //made up I presume it has something to do with passing/returning the instance of a class, but what? Is this syntax valid; if not why not and if so what does it mean? char & strcat ( char & destination, const char & source ); //made up (all of the function declarations, except the last made-up two, are from http://www.cplusplus.com )

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  • How to store and remove dynamically and automatic variable of generic data type in custum list data

    - by Vineel Kumar Reddy
    Hi I have created a List data structure implementation for generic data type with each node declared as following. struct Node { void *data; .... .... } So each node in my list will have pointer to the actual data(generic could be anything) item that should be stored in the list. I have following signature for adding a node to the list AddNode(struct List *list, void* eledata); the problem is when i want to remove a node i want to free even the data block pointed by *data pointer inside the node structure that is going to be freed. at first freeing of datablock seems to be straight forward free(data) // forget about the syntax..... But if data is pointing to a block created by malloc then the above call is fine....and we can free that block using free function int *x = (int*) malloc(sizeof(int)); *x = 10; AddNode(list,(void*)x); // x can be freed as it was created using malloc what if a node is created as following int x = 10; AddNode(list,(void*)&x); // x cannot be freed as it was not created using malloc Here we cannot call free on variable x!!!! How do i know or implement the functionality for both dynamically allocated variables and static ones....that are passed to my list.... Thanks in advance...

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  • A trivial Python SWIG error question

    - by Alex
    I am trying to get Python running with swig to do C/C++. I am running the tutorial here, 'building a python module'. When I do the call gcc -c example.c example_wrap.c -I /my_correct_path/python2.5 I get an error: my_correct_path/python2.5/pyport.h:761:2: error: #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)." example_wrap.c: In function 'SWIG_Python_ConvertFunctionPtr': example_wrap.c:2034: warning: initialization discards qualifiers from pointer target type example_wrap.c: In function 'SWIG_Python_FixMethods': example_wrap.c:3232: warning: initialization discards qualifiers from pointer target type It actually does create an example.o file, but it doesn't work. I am using python2.5 not 2.1 as in the example, is this a problem? The error (everything else is just a 'warning') says something about wrong platform. This is a 64bit machine; is this a problem? Is my gcc configured wrong for my machine? How do I get past this? UPDATE: I am still having problems. How do I actually implement this "fix"?

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  • C++ polymorphism, function calls

    - by moai
    Okay, I'm pretty inexperienced as a programmer, let alone in C++, so bear with me here. What I wanted to do was to have a container class hold a parent class pointer and then use polymorphism to store a child class object. The thing is that I want to call one of the child class's functions through the parent class pointer. Here's a sort of example of what I mean in code: class SuperClass { public: int x; } class SubClass : public SuperClass { public: void function1() { x += 1; } } class Container { public: SuperClass * alpha; Container(SuperClass& beta) { alpha = beta; } } int main() { Container cont = new Container(new SubClass); } (I'm not sure that's right, I'm still really shaky on pointers. I hope it gets the point across, at least.) So, I'm not entirely sure whether I can do this or not. I have a sneaking suspicion the answer is no, but I want to be sure. If someone has another way to accomplish this sort of thing, I'd be glad to hear it.

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  • Basic problems (type inference or something else?) in Objective-C/Cocoa.

    - by Matt
    Hi, Apologies for how basic these questions are to some. Just started learning Cocoa, working through Hillegass' book, and am trying to write my first program (a GUI Cocoa app that counts the number of characters in a string). I tried this: NSString *string = [textField stringValue]; NSUInteger *stringLength = [string length]; NSString *countString = (@"There are %u characters",stringLength); [label setStringValue:countString]; But I'm getting errors like: Incompatible pointer conversion initializing 'NSUInteger' (aka 'unsigned long'), expected 'NSUInteger *'[-pedantic] for the first line, and this for the second line: Incompatible pointer types initializing 'NSUInteger *', expected 'NSString *' [-pedantic] I did try this first, but it didn't work either: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] On a similar note, I've only written in easy scripting languages before now, and I'm not sure when I should be allocing/initing objects and when I shouldn't. For example, when is it okay to do this: NSString *myString = @"foo"; or int *length = 5; instead of this: NSString *myString = [[NSString alloc] initWithString:"foo"]; And which ones should I be putting into the header files? I did check Apple's documentation, and CocoaDev, and the book I'm working for but without luck. Maybe I'm looking in the wrong places.. Thanks to anyone who takes the time to reply this: it's appreciated, and thanks for being patient with a beginner. We all start somewhere. EDIT Okay, I tried the following again: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] And it actually worked this time. Not sure why it didn't the first time, though I think I might have typed %d instead of %u by mistake. However I still don't understand why the code I posted at the top of my original post doesn't work, and I have no idea what the errors mean, and I'd very much like to know because it seems like I'm missing something important there.

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  • C to Assembly code - what does it mean

    - by Smith
    I'm trying to figure out exactly what is going on with the following assembly code. Can someone go down line by line and explain what is happening? I input what I think is happening (see comments) but need clarification. .file "testcalc.c" .section .rodata.str1.1,"aMS",@progbits,1 .LC0: .string "x=%d, y=%d, z=%d, result=%d\n" .text .globl main .type main, @function main: leal 4(%esp), %ecx // establish stack frame andl $-16, %esp // decrement %esp by 16, align stack pushl -4(%ecx) // push original stack pointer pushl %ebp // save base pointer movl %esp, %ebp // establish stack frame pushl %ecx // save to ecx subl $36, %esp // alloc 36 bytes for local vars movl $11, 8(%esp) // store 11 in z movl $6, 4(%esp) // store 6 in y movl $2, (%esp) // store 2 in x call calc // function call to calc movl %eax, 20(%esp) // %esp + 20 into %eax movl $11, 16(%esp) // WHAT movl $6, 12(%esp) // WHAT movl $2, 8(%esp) // WHAT movl $.LC0, 4(%esp) // WHAT?!?! movl $1, (%esp) // move result into address of %esp call __printf_chk // call printf function addl $36, %esp // WHAT? popl %ecx popl %ebp leal -4(%ecx), %esp ret .size main, .-main .ident "GCC: (Ubuntu 4.3.3-5ubuntu4) 4.3.3" .section .note.GNU-stack,"",@progbits Original code: #include <stdio.h> int calc(int x, int y, int z); int main() { int x = 2; int y = 6; int z = 11; int result; result = calc(x,y,z); printf("x=%d, y=%d, z=%d, result=%d\n",x,y,z,result); }

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  • useer degined Copy ctor, and copy-ctors further down the chain - compiler bug ? programers brainbug

    - by J.Colmsee
    Hi. i have a little problem, and I am not sure if it's a compiler bug, or stupidity on my side. I have this struct : struct BulletFXData { int time_next_fx_counter; int next_fx_steps; Particle particles[2];//this is the interesting one ParticleManager::ParticleId particle_id[2]; }; The member "Particle particles[2]" has a self-made kind of smart-ptr in it (resource-counted texture-class). this smart-pointer has a default constructor, that initializes to the ptr to 0 (but that is not important) I also have another struct, containing the BulletFXData struct : struct BulletFX { BulletFXData data; BulletFXRenderFunPtr render_fun_ptr; BulletFXUpdateFunPtr update_fun_ptr; BulletFXExplosionFunPtr explode_fun_ptr; BulletFXLifetimeOverFunPtr lifetime_over_fun_ptr; BulletFX( BulletFXData data, BulletFXRenderFunPtr render_fun_ptr, BulletFXUpdateFunPtr update_fun_ptr, BulletFXExplosionFunPtr explode_fun_ptr, BulletFXLifetimeOverFunPtr lifetime_over_fun_ptr) :data(data), render_fun_ptr(render_fun_ptr), update_fun_ptr(update_fun_ptr), explode_fun_ptr(explode_fun_ptr), lifetime_over_fun_ptr(lifetime_over_fun_ptr) { } /* //USER DEFINED copy-ctor. if it's defined things go crazy BulletFX(const BulletFX& rhs) :data(data),//this line of code seems to do a plain memory-copy without calling the right ctors render_fun_ptr(render_fun_ptr), update_fun_ptr(update_fun_ptr), explode_fun_ptr(explode_fun_ptr), lifetime_over_fun_ptr(lifetime_over_fun_ptr) { } */ }; If i use the user-defined copy-ctor my smart-pointer class goes crazy, and it seems that calling the CopyCtor / assignment operator aren't called as they should. So - does this all make sense ? it seems as if my own copy-ctor of struct BulletFX should do exactly what the compiler-generated would, but it seems to forget to call the right constructors down the chain. compiler bug ? me being stupid ? Sorry about the big code, some small example could have illustrated too. but often you guys ask for the real code, so well - here it is :D

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  • Error with my Android Application httpGet

    - by Coombes
    Basically I'm getting a strange issue with my Android application, it's supposed to grab a JSON Array and print out some values, the class looks like this: ShowComedianActivity.class package com.example.connecttest; public class ShowComedianActivity extends Activity{ TextView name; TextView add; TextView email; TextView tel; String id; // Progress Dialog private ProgressDialog pDialog; //JSON Parser class JSONParser jsonParser = new JSONParser(); // Single Comedian url private static final String url_comedian_details = "http://86.9.71.17/connect/get_comedian_details.php"; // JSON Node names private static final String TAG_SUCCESS = "success"; private static final String TAG_COMEDIAN = "comedian"; private static final String TAG_ID = "id"; private static final String TAG_NAME = "name"; private static final String TAG_ADDRESS = "address"; private static final String TAG_EMAIL = "email"; private static final String TAG_TEL = "tel"; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.show_comedian); // Getting Comedian Details from intent Intent i = getIntent(); // Getting id from intent id = i.getStringExtra(TAG_ID); new GetComedianDetails().execute(); } class GetComedianDetails extends AsyncTask<String, String, String>{ protected void onPreExecute(){ super.onPreExecute(); pDialog = new ProgressDialog(ShowComedianActivity.this); pDialog.setMessage("Fetching Comedian details. Please wait..."); pDialog.setIndeterminate(false); pDialog.setCancelable(true); pDialog.show(); } @Override protected String doInBackground(String... params) { runOnUiThread(new Runnable(){ public void run(){ int success; try{ //Building parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("id",id)); // Getting comedian details via HTTP request // Uses a GET request JSONObject json = jsonParser.makeHttpRequest(url_comedian_details, "GET", params); // Check Log for json response Log.d("Single Comedian details", json.toString()); //JSON Success tag success = json.getInt(TAG_SUCCESS); if(success == 1){ // Succesfully received product details JSONArray comedianObj = json.getJSONArray(TAG_COMEDIAN); //JSON Array // get first comedian object from JSON Array JSONObject comedian = comedianObj.getJSONObject(0); // comedian with id found name = (TextView) findViewById(R.id.name); add = (TextView) findViewById(R.id.add); email = (TextView) findViewById(R.id.email); tel = (TextView) findViewById(R.id.tel); // Set text to details name.setText(comedian.getString(TAG_NAME)); add.setText(comedian.getString(TAG_ADDRESS)); email.setText(comedian.getString(TAG_EMAIL)); tel.setText(comedian.getString(TAG_TEL)); } } catch (JSONException e){ e.printStackTrace(); } } }); return null; } } } And my JSON Parser class looks like: package com.example.connecttest; public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } // function get json from url // by making HTTP POST or GET method public JSONObject makeHttpRequest(String url, String method, List<NameValuePair> params) { // Making HTTP request try { // check for request method if(method == "POST"){ // request method is POST // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); }else if(method == "GET"){ // request method is GET DefaultHttpClient httpClient = new DefaultHttpClient(); String paramString = URLEncodedUtils.format(params, "utf-8"); url += "?" + paramString; HttpGet httpGet = new HttpGet(url); HttpResponse httpResponse = httpClient.execute(httpGet); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } Now when I run a debug it's querying the correct address with ?id=1 on the end of the URL, and when I navigate to that url I get the following JSON Array: {"success":1,"comedian":[{"id":"1","name":"Michael Coombes","address":"5 Trevethenick Road","email":"[email protected]","tel":"xxxxxxxxxxxx"}]} However my app just crashes, the log-cat report looks like this: 03-22 02:05:02.140: E/Trace(3776): error opening trace file: No such file or directory (2) 03-22 02:05:04.590: E/AndroidRuntime(3776): FATAL EXCEPTION: main 03-22 02:05:04.590: E/AndroidRuntime(3776): android.os.NetworkOnMainThreadException 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connect(IoBridge.java:112) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.Socket.connect(Socket.java:842) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.JSONParser.makeHttpRequest(JSONParser.java:62) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.ShowComedianActivity$GetComedianDetails$1.run(ShowComedianActivity.java:89) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.handleCallback(Handler.java:615) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.dispatchMessage(Handler.java:92) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Looper.loop(Looper.java:137) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.app.ActivityThread.main(ActivityThread.java:4745) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invokeNative(Native Method) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invoke(Method.java:511) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 03-22 02:05:04.590: E/AndroidRuntime(3776): at dalvik.system.NativeStart.main(Native Method) From this I'm guessing the error is in the jsonParser.makeHttpRequest however I can't for the life of me figure out what's going wrong and was hoping someone brighter than I could illuminate me.

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  • Multithreaded linked list traversal

    - by Rob Bryce
    Given a (doubly) linked list of objects (C++), I have an operation that I would like multithread, to perform on each object. The cost of the operation is not uniform for each object. The linked list is the preferred storage for this set of objects for a variety of reasons. The 1st element in each object is the pointer to the next object; the 2nd element is the previous object in the list. I have solved the problem by building an array of nodes, and applying OpenMP. This gave decent performance. I then switched to my own threading routines (based off Windows primitives) and by using InterlockedIncrement() (acting on the index into the array), I can achieve higher overall CPU utilization and faster through-put. Essentially, the threads work by "leap-frog'ing" along the elements. My next approach to optimization is to try to eliminate creating/reusing the array of elements in my linked list. However, I'd like to continue with this "leap-frog" approach and somehow use some nonexistent routine that could be called "InterlockedCompareDereference" - to atomically compare against NULL (end of list) and conditionally dereference & store, returning the dereferenced value. I don't think InterlockedCompareExchangePointer() will work since I cannot atomically dereference the pointer and call this Interlocked() method. I've done some reading and others are suggesting critical sections or spin-locks. Critical sections seem heavy-weight here. I'm tempted to try spin-locks but I thought I'd first pose the question here and ask what other people are doing. I'm not convinced that the InterlockedCompareExchangePointer() method itself could be used like a spin-lock. Then one also has to consider acquire/release/fence semantics... Ideas? Thanks!

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  • Is the C++ compiler optimizer allowed to break my destructor ability to be called multiple times?

    - by sharptooth
    We once had an interview with a very experienced C++ developer who couldn't answer the following question: is it necessary to call the base class destructor from the derived class destructor in C++? Obviously the answer is no, C++ will call the base class destructor automagically anyway. But what if we attempt to do the call? As I see it the result will depend on whether the base class destructor can be called twice without invoking erroneous behavior. For example in this case: class BaseSafe { public: ~BaseSafe() { } private: int data; }; class DerivedSafe { public: ~DerivedSafe() { BaseSafe::~BaseSafe(); } }; everything will be fine - the BaseSafe destructor can be called twice safely and the program will run allright. But in this case: class BaseUnsafe { public: BaseUnsafe() { buffer = new char[100]; } ~BaseUnsafe () { delete[] buffer; } private: char* buffer; }; class DerivedUnsafe { public: ~DerivedUnsafe () { BaseUnsafe::~BaseUnsafe(); } }; the explicic call will run fine, but then the implicit (automagic) call to the destructor will trigger double-delete and undefined behavior. Looks like it is easy to avoid the UB in the second case. Just set buffer to null pointer after delete[]. But will this help? I mean the destructor is expected to only be run once on a fully constructed object, so the optimizer could decide that setting buffer to null pointer makes no sense and eliminate that code exposing the program to double-delete. Is the compiler allowed to do that?

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  • User controls Stopped working after Migration from 3.7 to 5.2

    - by user1400290
    I recently Migrated my 3.7 sp4 project to 5.2, but I had issues while doing so. Currently, my user controls are not working after migration in 5.2 project. Below is the code: User Control Code: <%@ Control Language="C#" AutoEventWireup="true" CodeFile="SiteMenu.ascx.cs" Inherits="UserControls_Nav_SiteMenu" %> <%@ Register TagPrefix="telerik" Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" %> <asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" ShowStartingNode="false" /> <telerik:RadMenu ID="RadMenu1" runat="server" DataSourceID="SitemapDataSource1" OnItemDataBound="RadMenu1_ItemDataBound"> </telerik:RadMenu> User Control's Class code: using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.ComponentModel; using System.Drawing; using Telerik; using Telerik.Cms; using Telerik.Cms.Web; using Telerik.Web.UI; using Telerik.Caching; using Telerik.Cms.Web.UI; [DefaultProperty("StartingNodeOffset")] public partial class UserControls_Nav_SiteMenu : System.Web.UI.UserControl, ICacheableObject { protected void Page_Load(object sender, EventArgs e) { } protected override void Render(HtmlTextWriter writer) { // Checks if this is called by the Search Indexer and does not render anything if so. // Navigation controls are present in every page and should NOT be indexed multiple times. if (!CmsContext.IsRequestCrawler(this.Context)) base.Render(writer); } #region Data Fields private bool hideUrlForGroupPages = false; private string selectedItemCssClass = "selectedItem"; #endregion #region Properties [Browsable(true)] [Category("Behavior")] public int LastExpandLevel { get { if (this.RadMenu1.MaxDataBindDepth < 0) return 0; return this.RadMenu1.MaxDataBindDepth; } set { if (value == 0) this.RadMenu1.MaxDataBindDepth = -1; else this.RadMenu1.MaxDataBindDepth = value; } } [Browsable(true)] [Category("Behavior")] public int ExpandDelay { get { return this.RadMenu1.ExpandDelay; } set { this.RadMenu1.ExpandDelay = value; } } [Browsable(true)] [Category("Behavior")] public bool ClickToOpen { get { return this.RadMenu1.ClickToOpen; } set { this.RadMenu1.ClickToOpen = value; } } [Browsable(true)] [Category("Behavior")] [DefaultValue(false)] public bool HideUrlForGroupPages { get { return this.hideUrlForGroupPages; } set { this.hideUrlForGroupPages = value; } } [Browsable(true)] [Category("Appearance")] public string SelectedItemCssClass { get { return this.selectedItemCssClass; } set { this.selectedItemCssClass = value; } } [Browsable(true)] [Category("Appearance")] public string CssClass { get { return this.RadMenu1.CssClass; } set { this.RadMenu1.CssClass = value; } } [Browsable(true)] public RadMenu Menu { get { return this.RadMenu1; } set { this.RadMenu1 = value; } } [Browsable(true)] [Category("Navigation")] public int StartingNodeOffset { get { return this.SiteMapDataSource1.StartingNodeOffset; } set { this.SiteMapDataSource1.StartingNodeOffset = value; } } [WebEditor("Telerik.Cms.Web.UI.UrlEditorWrapper, Telerik.Cms")] [Browsable(true)] [Category("Navigation")] public string StartingNodeUrl { get { return this.SiteMapDataSource1.StartingNodeUrl; } set { this.SiteMapDataSource1.StartingNodeUrl = value; } } [Browsable(true)] [Category("Navigation")] public bool StartFromCurrentNode { get { return this.SiteMapDataSource1.StartFromCurrentNode; } set { this.SiteMapDataSource1.StartFromCurrentNode = value; } } [Browsable(true)] [Category("Navigation")] public bool ShowStartingNode { get { return this.SiteMapDataSource1.ShowStartingNode; } set { this.SiteMapDataSource1.ShowStartingNode = value; } } /// <summary>(Exposed from contained RadMenu.)</summary> [Browsable(true)] [Category("Appearance")] public string SkinID { get { return this.RadMenu1.SkinID; } set { this.RadMenu1.SkinID = value; } } [Browsable(true)] [Category("Appearance")] public string Skin { get { return this.RadMenu1.Skin; } set { this.RadMenu1.Skin = value; } } #endregion #region Methods public void RadMenu1_ItemDataBound(object sender, RadMenuEventArgs e) { CmsSiteMapNode node = e.Item.DataItem as CmsSiteMapNode; if (this.hideUrlForGroupPages) { if (node != null) { // save the PageID in the attributes of the menu item e.Item.Attributes.Add("PageID", node.Key); if (node.PageType == CmsPageType.Group) { e.Item.NavigateUrl = ""; } } } if (node.CmsPage != null) { if (node.CmsPage.PageType == CmsPageType.External) { e.Item.Target = "_blank"; } } } #endregion #region ICacheableObject Members public System.Web.Caching.CacheDependency[] GetDependencies() { CmsSiteMapProvider provider = null; if (!String.IsNullOrEmpty(this.SiteMapDataSource1.SiteMapProvider)) provider = SiteMap.Providers[this.SiteMapDataSource1.SiteMapProvider] as CmsSiteMapProvider; else provider = SiteMap.Provider as CmsSiteMapProvider; if (provider != null) { return new System.Web.Caching.CacheDependency[]{ provider.CloneCacheDependency()}; } return null; } #endregion } When I edit the Template(in Admin mode), the following error is displayed in control location: Both DataSource and DataSourceID are defined on 'RadMenu1'. Remove one definition. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.InvalidOperationException: Both DataSource and DataSourceID are defined on 'RadMenu1'. Remove one definition. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [InvalidOperationException: Both DataSource and DataSourceID are defined on 'RadMenu1'. Remove one definition.] System.Web.UI.WebControls.DataBoundControl.ConnectToDataSourceView() +3234866 System.Web.UI.WebControls.DataBoundControl.OnLoad(EventArgs e) +28 System.Web.UI.Control.LoadRecursive() +71 System.Web.UI.Control.LoadRecursive() +190 System.Web.UI.Control.LoadRecursive() +190 System.Web.UI.Control.AddedControl(Control control, Int32 index) +11422584 System.Web.UI.Control.EnsureChildControls() +182 System.Web.UI.Control.PreRenderRecursiveInternal() +60 System.Web.UI.Control.PreRenderRecursiveInternal() +222 System.Web.UI.Control.PreRenderRecursiveInternal() +222 System.Web.UI.Control.PreRenderRecursiveInternal() +222 System.Web.UI.Control.PreRenderRecursiveInternal() +222 System.Web.UI.Control.PreRenderRecursiveInternal() +222 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4201 Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272 but I searched in my code as you can see above there's only DataSourceID is defined. What should I do? Thanks

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  • C++ trouble with pointers to objects

    - by Zibd
    I have a class with a vector of pointers to objects. I've introduced some elements on this vector, and on my main file I've managed to print them and add others with no problems. Now I'm trying to remove an element from that vector and check to see if it's not NULL but it is not working. I'm filling it with on class Test: Other *a = new Other(1,1); Other *b = new Other(2,2); Other *c = new Other(3,3); v->push_back(a); v->push_back(b); v->push_back(c); And on my main file I have: Test t; (...) Other *pointer = t.vect->at(0); delete t.vect->at(0); t.vect->erase(t.vect->begin()); if (pointer == NULL) { cout << "Nothing here.."; } // Never enters here..

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  • Is there a way to find out whether a class is a direct base of another class?

    - by user176168
    Hi I'm wondering whether there is a way to find out whether a class is a direct base of another class i.e. in boost type trait terms a is_direct_base_of function. As far as I can see boost doesn't see to support this kind of functionality which leads me to think that its impossible with the current C++ standard. The reason I want it is to do some validation checking on two macro's that are used for a reflection system to specify that one class is derived from another e.g. header.h: #define BASE A #define DERIVED B class A {}; class B : public A { #include <rtti.h> }; rtti.h: // I want to check that the two macro's are correct with a compile time assert Rtti<BASE, DERIVED> m_rtti; Although the macro's seem unnecessary in this simple example in my real world scenario rtti.h is a lot more complex. One possible avenue would be to compare the size of the this pointer with the size of a this pointer cast to the base type and some how trying to figure out whether its the size of the base class itself away or something (yeah your right I don't know how that would work either! lol)

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  • How to put Listview items into String Array?

    - by user2851687
    Im developing an app and as the title says how to put items of listview into String array, not string array to listview but listview to string array. I've been searching for this but what I only found is putting String array items into listview. Please help me thank you in advance. To clarify this thread, the question is how to put listview items into String array. Thanks. :D Codes public class DailyPlanTab extends Activity implements OnItemClickListener { ListView dailyPlanList; ArrayList<DailyManager> taskList = new ArrayList<DailyManager>(); DatabaseDailyPlan db; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.dailyplan_layout); dailyPlanList = (ListView) findViewById(R.id.lvDailyPlanList); dailyPlanList.setOnItemClickListener(this); ImageView add = (ImageView) findViewById(R.id.ivDailyPlanAdd); add.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Intent newDailyIntent = new Intent(getApplicationContext(), NewDailyPlan.class); startActivity(newDailyIntent); } }); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); taskList.clear(); db = new DatabaseDailyPlan(getApplicationContext()); db.getWritableDatabase(); ArrayList<DailyManager> tempList = db.getTask(); for (int i = 0; i < tempList.size(); i++) { String getTask = tempList.get(i).getDaily_name(); String getDate = tempList.get(i).getDaily_date(); int getId = tempList.get(i).getDaily_id(); DailyManager dm = new DailyManager(); dm.setDaily_name(getTask); dm.setDaily_date(getDate); dm.setDaily_id(getId); taskList.add(dm); } dailyPlanList.setAdapter(new ListAdapter(this)); // db.close(); } public class ListAdapter extends BaseAdapter { LayoutInflater inflater; ViewHolder viewHolder; public ListAdapter(Context c) { // TODO Auto-generated constructor stub inflater = LayoutInflater.from(c); } @Override public int getCount() { // TODO Auto-generated method stub return taskList.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return position; } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub if (convertView == null) { convertView = inflater.inflate(R.layout.row_checklist_item, null); viewHolder = new ViewHolder(); viewHolder.taskTitle = (TextView) convertView .findViewById(R.id.tvCheckListItem); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder) convertView.getTag(); } viewHolder.taskTitle.setText("" + taskList.get(position).getDaily_name()); return convertView; } } public class ViewHolder { TextView taskTitle, taskDate; } @Override public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) { // TODO Auto-generated method stub int taskId = taskList.get(position).getDaily_id(); String taskName = taskList.get(position).getDaily_name(); String taskDate = taskList.get(position).getDaily_date(); Intent newPlan = new Intent(getApplicationContext(), DailyPlan.class); newPlan.putExtra("task_id", taskId); newPlan.putExtra("task_name", taskName); startActivity(newPlan); } next is the information of the item inside the listview public class DailyPlan extends Activity implements OnItemClickListener { final ArrayList<DailyManager> savedItems = new ArrayList<DailyManager>(); ListView checkList; Boolean nextItem = false; TempManager tm; DatabaseTemp dbTemp; Intent i; int taskId = -1; String taskName = " ", taskDate = null; DatabaseDailyPlan db; DailyManager dm; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.saved_dailyplan); checkList = (ListView) findViewById(R.id.lvCheckList); // checkList.setOnItemClickListener(this); try { i = getIntent(); taskId = i.getExtras().getInt("task_id"); taskName = i.getExtras().getString("task_name"); Toast.makeText(getApplicationContext(), "From new id is" + taskId, 5000).show(); } catch (Exception e) { } Button addList = (Button) findViewById(R.id.bAddList); addList.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub // openDialog("", false, -1); } }); if (nextItem) { // openDialog("", false, -1); } } public void refresh() { DailyPlan.this.onResume(); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); savedItems.clear(); dbTemp = new DatabaseTemp(getApplicationContext()); dbTemp.getWritableDatabase(); db = new DatabaseDailyPlan(getApplicationContext()); db.getWritableDatabase(); if (taskId != -1) { // / For Load ArrayList<DailyManager> savedList = db.getList(taskId); for (int i = 0; i < savedList.size(); i++) { String savedListItems = savedList.get(i).getDaily_list(); String savedListTitle = savedList.get(i).getDaily_name(); String savedListDate = savedList.get(i).getDaily_date(); int savedListId = savedList.get(i).getDaily_id(); DailyManager dm = new DailyManager(); dm.setDaily_list(savedListItems); dm.setDaily_name(savedListTitle); dm.setDaily_date(savedListDate); dm.setDaily_id(savedListId); savedItems.add(dm); } } else { // / For New } checkList.setAdapter(new ListAdapter(this)); } public class ListAdapter extends BaseAdapter { LayoutInflater inflater; ViewHolder viewHolder; public ListAdapter(Context c) { // TODO Auto-generated constructor stub inflater = LayoutInflater.from(c); } @Override public int getCount() { // TODO Auto-generated method stub return savedItems.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return position; } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub if (convertView == null) { convertView = inflater.inflate(R.layout.row_checklist_item, null); viewHolder = new ViewHolder(); viewHolder.checkListItem = (TextView) convertView .findViewById(R.id.tvCheckListItem); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder) convertView.getTag(); } viewHolder.checkListItem.setText(savedItems.get(position) .getDaily_list() + position); final int temp = position; return convertView; } } private class ViewHolder { TextView checkListItem; } @Override public void onItemClick(AdapterView<?> arg0, View arg1, int item, long arg3) { // TODO Auto-generated method stub // openDialog(savedItems.get(item).getDaily_name(), true, // savedItems.get(item).getDaily_id()); } }

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  • How to convert a list object to bigdecimal in prepared statement?

    - by user1103504
    I am using prepared statement for bulk insertion of records. Iam iterating a list which contains values and their dataTypes differ. One of the data type is BigDecimal and when i try to set calling preparedstatement, it is throwing null pointer exception. My code int count = 1; for (int j = 0; j < list.size(); j++) { if(list.get(j) instanceof Timestamp) { ps.setTimestamp(count, (Timestamp) list.get(j)); } else if(list.get(j) instanceof java.lang.Character) { ps.setString(count, String.valueOf(list.get(j))); } else if(list.get(j) instanceof java.math.BigDecimal) { ps.setBigDecimal(count, (java.math.BigDecimal)list.get(j)); } else { ps.setObject(count, list.get(j)); } count++; } I tried 2 ways to convert, casting the object and tried to create a new object of type BigDecimal ps.setBigDecimal(count, new BigDecimal(list.get(j).toString)); both donot solve my problem. It is throwing null pointer exception. help is appreciated. Thanks

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  • Why does VS2005 skip execution of lines when debugging managed C++ without optimizations?

    - by Sakin
    I ran into a rather odd behavior that I don't even know how to start describing. I wrote a piece of managed C++ code that makes calls to native methods. A (very) simplified version of the code would look like this (I know it looks like a full native function, just assume there is managed stuff being done all over the place): int somefunction(ptrHolder x) { // the accessptr method returns a native pointer if (x.accessptr() != nullptr) // I tried this with nullptr, NULL, 0) { try { x->doSomeNativeVeryImportantStuff(); // or whatever, doesn't matter } catch (SomeCustomExceptionClass &) { return 0; } } SomeOtherNativeClass::doStaticMagic(); return 1; } I compiled this code without optimizations using the /clr flag (VS.NET 2005, SP2) and when running it in the debugger I get to the if statement, since the pointer is actually null, I don't enter the if, but surprisingly, the cursor jumps directly to the return 1 statement, ignoring the doStaticMagic() method completely!!! When looking at the assembly code, I see that it really jumps directly to that line. If I force the debugger to enter the if block, I also jump to the return 1 statement after I press F10. Any ideas why this is happening? Thanks, Ariel

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  • HashMap Memory Leak because of Dynamic Array

    - by Jake M
    I am attempting to create my own HashMap to understand how they work. I am using an array of Linked Lists to store the values(strings) in my hashmap. I am creating the array like this: Node** list; Instead of this: Node* list[nSize]; This is so the array can be any size at runtime. But I think I am getting a memory leak because of how I am doing this. I dont know where the error is but when I run the following simple code the .exe crashes. Why is my application crashing and how can I fix it? Note: I am aware that using a vector would be much better than an array but this is just for learning and I want to challenge myself to create the hashmap using a 'Dynamic' Array. PS: is that the correct term(Dynamic Array) for the kind of array I am using? struct Node { // to implement }; class HashMap { public: HashMap(int dynSize) { *list = new Node[dynSize]; size = dynSize; for (int i=0; i<size; i++) list[i] = NULL; cout << "END\n"; } ~HashMap() { for (int i=0; i<size; i++) delete list[i]; } private: Node** list; // I could use a vector here but I am experimenting with a pointer to an array(pointer), also its more elegant int size; }; int main() { // When I run this application it crashes. Where is my memory leak? HashMap h(5); system("PAUSE"); return 0; }

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  • Templates, Function Pointers and C++0x

    - by user328543
    One of my personal experiments to understand some of the C++0x features: I'm trying to pass a function pointer to a template function to execute. Eventually the execution is supposed to happen in a different thread. But with all the different types of functions, I can't get the templates to work. #include `<functional`> int foo(void) {return 2;} class bar { public: int operator() (void) {return 4;}; int something(int a) {return a;}; }; template <class C> int func(C&& c) { //typedef typename std::result_of< C() >::type result_type; typedef typename std::conditional< std::is_pointer< C >::value, std::result_of< C() >::type, std::conditional< std::is_object< C >::value, std::result_of< typename C::operator() >::type, void> >::type result_type; result_type result = c(); return result; } int main(int argc, char* argv[]) { // call with a function pointer func(foo); // call with a member function bar b; func(b); // call with a bind expression func(std::bind(&bar::something, b, 42)); // call with a lambda expression func( [](void)->int {return 12;} ); return 0; } The result_of template alone doesn't seem to be able to find the operator() in class bar and the clunky conditional I created doesn't compile. Any ideas? Will I have additional problems with const functions?

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  • Using an embedded DB (SQLite / SQL Compact) for Message Passing within an app?

    - by wk1989
    Hello, Just out of curiosity, for applications that have a fairly complicated module tree, would something like sqlite/sql compact edition work well for message passing? So if I have modules containing data such as: \SubsystemA\SubSubSysB\ModuleB\ModuleDataC, \SubSystemB\SubSubSystemC\ModuleA\ModuleDataX Using traditional message passing/routing, you have to go through intermediate modules in order to pass a message to ModuleB to request say ModuleDataC. Instead of doing that, if we we simply store "\SubsystemA\SubSubSysB\ModuleB\ModuleDataC" in a sqlite database, getting that data is as simple as a sql query and needs no routing and passing stuff around. Has anyone done this before? Even if you haven't, do you foresee any issues & performance impact? The only concern I have right now would be the passing of custom types, e.g. if ModuleDataC is a custom data structure or a pointer, I'll need some way of storing the data structure into the DB or storing the pointer into the DB. Thanks, JW EDIT One usage case I haven't thought about is when you want to send a message from ModuleA to ModuleB to get ModuleB to do something rather than just getting/setting data. Is it possible to do this using an embedded DB? I believe callback from the DB would be needed, how feasible is this?

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  • C++ private inheritance and static members/types

    - by WearyMonkey
    I am trying to stop a class from being able to convert its 'this' pointer into a pointer of one of its interfaces. I do this by using private inheritance via a middle proxy class. The problem is that I find private inheritance makes all public static members and types of the base class inaccessible to all classes under the inheriting class in the hierarchy. class Base { public: enum Enum { value }; }; class Middle : private Base { }; class Child : public Middle { public: void Method() { Base::Enum e = Base::value; // doesn't compile BAD! Base* base = this; // doesn't compile GOOD! } }; I've tried this in both VS2008 (the required version) and VS2010, neither work. Can anyone think of a workaround? Or a different approach to stopping the conversion? Also I am curios of the behavior, is it just a side effect of the compiler implementation, or is it by design? If by design, then why? I always thought of private inheritance to mean that nobody knows Middle inherits from Base. However, the exhibited behavior implies private inheritance means a lot more than that, in-fact Child has less access to Base than any namespace not in the class hierarchy!

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  • Dependency injection in C++

    - by Yorgos Pagles
    This is also a question that I asked in a comment in one of Miško Hevery's google talks that was dealing with dependency injection but it got buried in the comments. I wonder how can the factory / builder step of wiring the dependencies together can work in C++. I.e. we have a class A that depends on B. The builder will allocate B in the heap, pass a pointer to B in A's constructor while also allocating in the heap and return a pointer to A. Who cleans up afterwards? Is it good to let the builder clean up after it's done? It seems to be the correct method since in the talk it says that the builder should setup objects that are expected to have the same lifetime or at least the dependencies have longer lifetime (I also have a question on that). What I mean in code: class builder { public: builder() : m_ClassA(NULL),m_ClassB(NULL) { } ~builder() { if (m_ClassB) { delete m_ClassB; } if (m_ClassA) { delete m_ClassA; } } ClassA *build() { m_ClassB = new class B; m_ClassA = new class A(m_ClassB); return m_ClassA; } }; Now if there is a dependency that is expected to last longer than the lifetime of the object we are injecting it into (say ClassC is that dependency) I understand that we should change the build method to something like: ClassA *builder::build(ClassC *classC) { m_ClassB = new class B; m_ClassA = new class A(m_ClassB, classC); return m_ClassA; } What is your preferred approach?

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  • C++, using one byte to store two variables

    - by 2di
    Hi All I am working on representation of the chess board, and I am planning to store it in 32 bytes array, where each byte will be used to store two pieces. (That way only 4 bits are needed per piece) Doing it in that way, results in a overhead for accessing particular index of the board. Do you think that, this code can be optimised or completely different method of accessing indexes can be used? c++ char getPosition(unsigned char* c, int index){ //moving pointer c+=(index>>1); //odd number if (index & 1){ //taking right part return *c & 0xF; }else { //taking left part return *c>>4; } } void setValue(unsigned char* board, char value, int index){ //moving pointer board+=(index>>1); //odd number if (index & 1){ //replace right part //save left value only 4 bits *board = (*board & 0xF0) + value; }else { //replacing left part *board = (*board & 0xF) + (value<<4); } } int main() { char* c = (char*)malloc(32); for (int i = 0; i < 64 ; i++){ setValue((unsigned char*)c, i % 8,i); } for (int i = 0; i < 64 ; i++){ cout<<(int)getPosition((unsigned char*)c, i)<<" "; if (((i+1) % 8 == 0) && (i > 0)){ cout<<endl; } } return 0; } I am equally interested in your opinions regarding chess representations, and optimisation of the method above, as a stand alone problem. Thanks a lot

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  • Stretch ListBox Items hit area to full width if the ListBox?

    - by Nicholas
    I've looked around for an answer on this, but the potential duplicates are more concerned with presentation than interaction. I have a basic list box, and each item's content is a simple string. The ListBox itself is stretched to fill it's grid container, but each ListBoxItem's hitarea does not mirror the ListBox width. It looks as if the hitarea (pointer contact area) for each item is only the width of the text content. How do I make this stretch all the way across, regardless of the text size. I've set HorizontalContentAlignment to Stretch, but this doesn't solve my problem. My only other guess is that the content is actually stretching, but the background is invisible and so not capturing the mouse pointer. <ListBox Grid.Row="1" x:Name="ProjectsListBox" DisplayMemberPath="Name" ItemsSource="{Binding Path=Projects}" SelectedItem="{Binding Path=SelectedProject}" HorizontalContentAlignment="Stretch"/> The XAML is pretty straight forward on this. If I mouse over the text in one of the items, then the entire width of the item becomes active. I guess I just need to know how to create an interactive background that is invisible.

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  • sIFR multiple calls don't work :(

    - by roxane
    Hello ! I'm trying to use sIFR on my menu and on my headers... but only one call works... the others that I put after never appear :(... Can somebody help me ? Note : I'm using the r436 and below is my code ... var segoe = { src: 'pathto/segoe.swf', ratios: [7, 1.58, 8, 1.49, 10, 1.5, 11, 1.45, 16, 1.46, 21, 1.44, 22, 1.41, 27, 1.42, 30, 1.41, 32, 1.4, 35, 1.41, 36, 1.4, 38, 1.39, 41, 1.4, 58, 1.39, 65, 1.38, 66, 1.39, 102, 1.38, 104, 1.37, 106, 1.38, 107, 1.37, 108, 1.38, 109, 1.37, 110, 1.38, 112, 1.37, 114, 1.38, 120, 1.37, 121, 1.38, 1.37] }; sIFR.activate(segoe); sIFR.replace(segoe, { selector: '#header ul li a span.title', css: ['.sIFR-root { text-align: center; font-size:13px; letter-spacing:2; font-weight: bold; text-transform:uppercase; cursor: pointer; color:#FFFFFF; background-color:#0C2C39; margin:0 3px; }'], wmode: 'transparent' }); sIFR.replace(segoe, { selector: 'h1', css: ['.sIFR-root { text-align: center; font-size:13px; letter-spacing:2; font-weight: bold; text-transform:uppercase; cursor: pointer; color:#000; background-color:#fff; margin:0 3px; }'] });

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