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  • Modifying bundled properties from visitor

    - by ravenspoint
    How should I modify the bundled properties of a vertex from inside a visitor? I would like to use the simple method of sub-scripting the graph, but the graph parameter passed into the visitor is const, so compiler disallows changes. I can store a reference to the graph in the visitor, but this seems weird. /** A visitor which identifies vertices as leafs or trees */ class bfs_vis_leaf_finder:public default_bfs_visitor { public: /** Constructor @param[in] total reference to int variable to store total number of leaves @param[in] g reference to graph ( used to modify bundled properties ) */ bfs_vis_leaf_finder( int& total, graph_t& g ) : myTotal( total ), myGraph( g ) { myTotal = 0; } /** Called when the search finds a new vertex If the vertex has no children, it is a leaf and the total leaf count is incremented */ template <typename Vertex, typename Graph> void discover_vertex( Vertex u, Graph& g) { if( out_edges( u, g ).first == out_edges( u, g ).second ) { myTotal++; //g[u].myLevel = s3d::cV::leaf; myGraph[u].myLevel = s3d::cV::leaf; } else { //g[u].myLevel = s3d::cV::tree; myGraph[u].myLevel = s3d::cV::tree; } } int& myTotal; graph_t& myGraph; };

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  • [Java] Safe way of exposing keySet().

    - by Jake
    This must be a fairly common occurrence where I have a map and wish to thread-safely expose its key set: public MyClass { Map<String,String> map = // ... public final Set<String> keys() { // returns key set } } Now, if my "map" is not thread-safe, this is not safe: public final Set<String> keys() { return map.keySet(); } And neither is: public final Set<String> keys() { return Collections.unmodifiableSet(map.keySet()); } So I need to create a copy, such as: public final Set<String> keys() { return new HashSet(map.keySet()); } However, this doesn't seem safe either because that constructor traverses the elements of the parameter and add()s them. So while this copying is going on, a ConcurrentModificationException can happen. So then: public final Set<String> keys() { synchronized(map) { return new HashSet(map.keySet()); } } seems like the solution. Does this look right?

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  • Why some pictures are are crooked aftes using my function?

    - by Miko Kronn
    struct BitmapDataAccessor { private readonly byte[] data; private readonly int[] rowStarts; public readonly int Height; public readonly int Width; public BitmapDataAccessor(byte[] data, int width, int height) { this.data = data; this.Height = height; this.Width = width; rowStarts = new int[height]; for (int y = 0; y < Height; y++) rowStarts[y] = y * width; } public byte this[int x, int y, int color] // Maybe use an enum with Red = 0, Green = 1, and Blue = 2 members? { get { return data[(rowStarts[y] + x) * 3 + color]; } set { data[(rowStarts[y] + x) * 3 + color] = value; } } public byte[] Data { get { return data; } } } public static byte[, ,] Bitmap2Byte(Bitmap obraz) { int h = obraz.Height; int w = obraz.Width; byte[, ,] wynik = new byte[w, h, 3]; BitmapData bd = obraz.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb); int bytes = Math.Abs(bd.Stride) * h; byte[] rgbValues = new byte[bytes]; IntPtr ptr = bd.Scan0; System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes); BitmapDataAccessor bda = new BitmapDataAccessor(rgbValues, w, h); for (int i = 0; i < h; i++) { for (int j = 0; j < w; j++) { wynik[j, i, 0] = bda[j, i, 2]; wynik[j, i, 1] = bda[j, i, 1]; wynik[j, i, 2] = bda[j, i, 0]; } } obraz.UnlockBits(bd); return wynik; } public static Bitmap Byte2Bitmap(byte[, ,] tablica) { if (tablica.GetLength(2) != 3) { throw new NieprawidlowyWymiarTablicyException(); } int w = tablica.GetLength(0); int h = tablica.GetLength(1); Bitmap obraz = new Bitmap(w, h, PixelFormat.Format24bppRgb); for (int i = 0; i < w; i++) { for (int j = 0; j < h; j++) { Color kol = Color.FromArgb(tablica[i, j, 0], tablica[i, j, 1], tablica[i, j, 2]); obraz.SetPixel(i, j, kol); } } return obraz; } Now, if I do: private void btnLoad_Click(object sender, EventArgs e) { if (dgOpenFile.ShowDialog() == DialogResult.OK) { try { Bitmap img = new Bitmap(dgOpenFile.FileName); byte[, ,] tab = Grafika.Bitmap2Byte(img); picture.Image = Grafika.Byte2Bitmap(tab); picture.Size = img.Size; } catch (Exception ex) { MessageBox.Show(ex.Message); } } } Most of pictures are handled correctly butsome not. Example of picture that doesn't work: It produce following result (this is only fragment of picture) : Why is that?

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  • Vector does reallocation on every push_back

    - by Amrish
    IDE - Visual Studio 2008, Visual C++ I have a custom class Class1 with a copy constructor to it. I also have a vector Data is inserted using the following code Class1* objClass1; vector<Class1> vClass1; for(int i=0;i<1000;i++) { objClass1 = new Class1(); vClass1.push_back(*objClass1); delete objClass1; } Now on every insert, the vector gets re-allocated and all the existing contents are copied to new locations. For example, if the vector has 5 elements and if I insert the 6th one, the previous 5 elements along with the new one gets copied to a new location (I figured it out by adding log statements in the copy constructors.) On using reserve(), this however does not happen as expected! I have the following questions Is it mandatory to always use the reserve statement? Does vector does a reallocation every time I do a push_back; or does it happen because I am debugging?

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  • How to find all initializations of instance variables in a Java package?

    - by Hank Gay
    I'm in the midst of converting a legacy app to Spring. As part of the transition, we're converting our service classes from an "instantiate new ones whenever you need one" style to a Springleton style, so I need a way to make sure they don't have any state. I'm comfortable on the *nix command-line, and I have access to IntelliJ (this strikes me as a good fit for Structural Search and Replace, if I could figure out how to use it), and I could track down an Eclipse install, if that would help. I just want to make absolutely sure I've found all the possible problems. UPDATE: Sorry for the confusion. I don't have a problem finding places where the old constructor was being called. What I'm looking for is a "bullet-proof" why to search all 100+ service classes for any sort of internal state. The most obvious one I could think of (and the only one I've really found so far) is cases where we use memoization in the classes, so they have instance variables that get initialized internally instead of via Spring. This means that when the same Springleton gets used for different requests, data can leak between them. Thanks.

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  • Proper structure for dependency injection (using Guice)

    - by David B.
    I would like some suggestions and feedback on the best way to structure dependency injection for a system with the structure described below. I'm using Guice and thus would prefer solutions centered around it's annotation-based declarations, not XML-heavy Spring-style configuration. Consider a set of similar objects, Ball, Box, and Tube, each dependent on a Logger, supplied via the constructor. (This might not be important, but all four classes happen to be singletons --- of the application, not Gang-of-Four, variety.) A ToyChest class is responsible for creating and managing the three shape objects. ToyChest itself is not dependent on Logger, aside from creating the shape objects which are. The ToyChest class is instantiated as an application singleton in a Main class. I'm confused about the best way to construct the shapes in ToyChest. I either (1) need access to a Guice Injector instance already attached to a Module binding Logger to an implementation or (2) need to create a new Injector attached to the right Module. (1) is accomplished by adding an @Inject Injector injectorfield to ToyChest, but this feels weird because ToyChest doesn't actually have any direct dependencies --- only those of the children it instantiates. For (2), I'm not sure how to pass in the appropriate Module. Am I on the right track? Is there a better way to structure this? The answers to this question mention passing in a Provider instead of using the Injector directly, but I'm not sure how that is supposed to work. EDIT: Perhaps a more simple question is: when using Guice, where is the proper place to construct the shapes objects? ToyChest will do some configuration with them, but I suppose they could be constructed elsewhere. ToyChest (as the container managing them), and not Main, just seems to me like the appropriate place to construct them.

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  • Gap between Navbar and Jumbotron

    - by DDK
    I am building I suppose you could call a template for the site I am going to build however I am still pretty new to bootstrap and thus have trouble figuring which CSS rules are affecting elements etc. The problem I am having is I cannot get the Jumbotron unit to sit flush with the bottom of the navbar. I have found a few questions on here about the same problem but the solutions did not work. Here is my code </head> <body> <div class="row"> <div> <img src="http://placehold.it/1600x300" width="100%"> </div> <!-- Static navbar --> <div class="navbar navbar-default navbar-static-top" role="navigation"> <div class="container"> <div class="navbar-header"> <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse"> <span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button> </div> <div class="navbar-collapse collapse"> <ul class="nav nav-justified" id="myNav"> <li class="active"><a href="#">Home</a></li> <li><a href="#about">About</a></li> <li><a href="#contact">Contact</a></li> <li><a href="#contact">Services</a></li> </ul> </div><!--/.nav-collapse --> </div> </div> <div class="jumbotron" id="openingtext"> This is where the opening sale text will go </div> <div class="container"> <!-- Example row of columns --> <div class="row"> <div class="col-md-4"> <h2>Heading</h2> <p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p> <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p> </div> <div class="col-md-4"> <h2>Heading</h2> I would provide the css but as it is all being pulled from an unchanged version of bootstrap and my stylesheet.css has nothing relating to any of these ids etc it seems pointless to do so. I look forward to hearing your solutions guys and girls

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  • C++ - Need to learn some basics in a short while

    - by Rubys
    For reasons I will spare you, I have two weeks to learn some C++. I can learn alone just fine, but I need a good source. I don't think I have time to go through an entire book, and so I need some cliff notes, or possibly specific chapters/specialized resources I need to look up. I know my Asm/C/C# well, and so anything inherited from C, or any OOP is not needed. What I do need is some sources on the following subjects(I have a page that specifies what is needed, this is basically it, but I trimmed what I know): new/delete in C++ (as opposed to C#). Overloading cin/cout. Constructor, Destructor and MIL. Embedded Objects. References. Templates. If you feel some basic C++ concept that is not shared with C/C# is not included on this list, feel free to enter those as well. But the above subjects are the ones I'm supposed to roughly know in two week's time. Any help would be appreciated, thanks.

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  • how to Clean up(destructor) a dynamic Array of pointers??

    - by Ahmed Sharara
    Is that Destructor is enough or do I have to iterate to delete the new nodes?? #include "stdafx.h" #include<iostream> using namespace std; struct node{ int row; int col; int value; node* next_in_row; node* next_in_col; }; class MultiLinkedListSparseArray { private: char *logfile; node** rowPtr; node** colPtr; // used in constructor node* find_node(node* out); node* ins_node(node* ins,int col); node* in_node(node* ins,node* z); node* get(node* in,int row,int col); bool exist(node* so,int row,int col); //add anything you need public: MultiLinkedListSparseArray(int rows, int cols); ~MultiLinkedListSparseArray(); void setCell(int row, int col, int value); int getCell(int row, int col); void display(); void log(char *s); void dump(); }; MultiLinkedListSparseArray::MultiLinkedListSparseArray(int rows,int cols){ rowPtr=new node* [rows+1]; colPtr=new node* [cols+1]; for(int n=0;n<=rows;n++) rowPtr[n]=NULL; for(int i=0;i<=cols;i++) colPtr[i]=NULL; } MultiLinkedListSparseArray::~MultiLinkedListSparseArray(){ // is that destructor enough?? cout<<"array is deleted"<<endl; delete [] rowPtr; delete [] colPtr; }

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  • Looking for suggestions on how to reuse AlertDialogs to confirm actions of contextual menus on the items of an ActivityList

    - by Ozone
    I use a ListActivity to display a list of items. The user can long-press an item in the list to display a contextual menu. This menu contains among other things an option to delete the long-pressed item. When the user selects this option, a dialog pops up asking for confirmation of the deletion. Upon confirmation, the item is deleted from the list. I would like to reuse the AlertDialog as much as possible. My attempts at using onPrepareDialog(int, View, Bundle) have been defeated by the fact that the Bundle is not passed to the DialogInterface.OnClickListener. I end up having to recreate a listener on every invocation. I see several ways to solve this: recreate the dialog on every occasion (pros: simple, cons: wasteful) keep the DialogInterface.OnClickListener in a field on the ListActivity and keep the item to be deleted as a field of the listener. (pros: no memory waste, cons: need to manage state). Q: is this safe? have onPrepareDialog update the title, and bind new View.OnClickListeners on the buttons of the AlertDialog. (pros: limit waste, cons: new View.OnClickListener on every invocation). If DialogInterface.OnClickListener accepted a Bundle, I wouldn't have to jump through hoops to keep track of the item being deleted. This is not a blocker, but I would love to see an elegant solution. I would love to hear your suggestions :) Here is the code for option #1, if you want to play with this: public class Example extends ListActivity { private static final int CONFIRM_DELETE_DIALOG = 1; private static final String POSITION_KEY = "position"; private ArrayAdapter<String> mAdapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mAdapter = new ArrayAdapter<String>( this, android.R.layout.simple_list_item_1, new String[] { "one", "two" }); setListAdapter(mAdapter); registerForContextMenu(getListView()); } @Override public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { super.onCreateContextMenu(menu, v, menuInfo); getMenuInflater().inflate(R.menu.my_lovely_menu, menu); } @Override public boolean onContextItemSelected(MenuItem item) { AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo(); switch (item.getItemId()) { case R.id.delete_item: Bundle bundle = new Bundle(); bundle.putInt(POSITION_KEY, info.position); showDialog(CONFIRM_DELETE_DIALOG, bundle); return true; default: return super.onContextItemSelected(item); } } @Override protected Dialog onCreateDialog(int id, Bundle args) { switch (id) { case CONFIRM_DELETE_DIALOG: final int position = args.getInt(POSITION_KEY); AlertDialog.Builder builder = new AlertDialog.Builder(); builder.setCancelable(false); builder.setTitle(String.format( getString(R.string.confirm_delete), mAdapter.getItem(position))); DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { switch (which) { case DialogInterface.BUTTON_POSITIVE: mAdapter.remove(mAdapter.getItem(position)); // Dismiss the dialog to ensure OnDismissListeners are notified. dialog.dismiss(); break; case DialogInterface.BUTTON_NEGATIVE: // Cancel the dialog to ensure OnCancelListeners are notified. dialog.cancel(); break; } // Remove the dialog so it is re-created next time it is required. removeDialog(CONFIRM_DELETE_DIALOG); } }; builder.setPositiveButton(android.R.string.yes, listener); builder.setNegativeButton(android.R.string.no, listener); return builder.create(); default: return super.onCreateDialog(id, args); } } }

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  • Usage Rails 3.0 beta 3 without ActiveRecoord ORM

    - by Anton
    Hi everybody! Just installed Rails 3.0 beta 3 in Windows 7. And started playing with some easy examples class SignupController < ApplicationController def index @user = User.new(params[:user]) if method.post? and @user.save redirect_to :root end end end class User def initialize(params = {}) @email = params[:email] @passw = params[:passw] end def save end end <div align="center"> <% form_for :user do |form| %> <%= form.label :email %> <%= form.text_field :email %><br /> <%= form.label :password %> <%= form.text_field :password %><br /> <%= form.submit :Register! %> <% end %> </div> When I go to /signup I'm getting this error NoMethodError in SignupController#index You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil.[] Is there a problem with constructor or what's wrong?Please, need your help!

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  • Insert a transformed integer_sequence into a variadic template argument?

    - by coderforlife
    How do you insert a transformed integer_sequence (or similar since I am targeting C++11) into a variadic template argument? For example I have a class that represents a set of bit-wise flags (shown below). It is made using a nested-class because you cannot have two variadic template arguments for the same class. It would be used like typedef Flags<unsigned char, FLAG_A, FLAG_B, FLAG_C>::WithValues<0x01, 0x02, 0x04> MyFlags. Typically, they will be used with the values that are powers of two (although not always, in some cases certain combinations would be made, for example one could imagine a set of flags like Read=0x1, Write=0x2, and ReadWrite=0x3=0x1|0x2). I would like to provide a way to do typedef Flags<unsigned char, FLAG_A, FLAG_B, FLAG_C>::WithDefaultValues MyFlags. template<class _B, template <class,class,_B> class... _Fs> class Flags { public: template<_B... _Vs> class WithValues : public _Fs<_B, Flags<_B,_Fs...>::WithValues<_Vs...>, _Vs>... { // ... }; }; I have tried the following without success (placed inside the Flags class, outside the WithValues class): private: struct _F { // dummy class which can be given to a flag-name template template <_B _V> inline constexpr explicit _F(std::integral_constant<_B, _V>) { } }; // we count the flags, but only in a dummy way static constexpr unsigned _count = sizeof...(_Fs<_B, _F, 1>); static inline constexpr _B pow2(unsigned exp, _B base = 2, _B result = 1) { return exp < 1 ? result : pow2(exp/2, base*base, (exp % 2) ? result*base : result); } template <_B... _Is> struct indices { using next = indices<_Is..., sizeof...(_Is)>; using WithPow2Values = WithValues<pow2(_Is)...>; }; template <unsigned N> struct build_indices { using type = typename build_indices<N-1>::type::next; }; template <> struct build_indices<0> { using type = indices<>; }; //// Another attempt //template < _B... _Is> struct indices { // using WithPow2Values = WithValues<pow2(_Is)...>; //}; //template <unsigned N, _B... _Is> struct build_indices // : build_indices<N-1, N-1, _Is...> { }; //template < _B... _Is> struct build_indices<0, _Is...> // : indices<_Is...> { }; public: using WithDefaultValues = typename build_indices<_count>::type::WithPow2Values; Of course, I would be willing to have any other alternatives to the whole situation (supporting both flag names and values in the same template set, etc). I have included a "working" example at ideone: http://ideone.com/NYtUrg - by "working" I mean compiles fine without using default values but fails with default values (there is a #define to switch between them). Thanks!

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  • java phone number validation....

    - by user69514
    Here is my problem: Create a constructor for a telephone number given a string in the form xxx-xxx-xxxx or xxx-xxxx for a local number. Throw an exception if the format is not valid. So I was thinking to validate it using a regular expression, but I don't know if I'm doing it correctly. Also what kind of exception would I have to throw? Do I need to create my own exception? public TelephoneNumber(String aString){ if(isPhoneNumberValid(aString)==true){ StringTokenizer tokens = new StringTokenizer("-"); if(tokens.countTokens()==3){ areaCode = Integer.parseInt(tokens.nextToken()); exchangeCode = Integer.parseInt(tokens.nextToken()); number = Integer.parseInt(tokens.nextToken()); } else if(tokens.countTokens()==2){ exchangeCode = Integer.parseInt(tokens.nextToken()); number = Integer.parseInt(tokens.nextToken()); } else{ //throw an excemption here } } } public static boolean isPhoneNumberValid(String phoneNumber){ boolean isValid = false; //Initialize reg ex for phone number. String expression = "(\\d{3})(\\[-])(\\d{4})$"; CharSequence inputStr = phoneNumber; Pattern pattern = Pattern.compile(expression); Matcher matcher = pattern.matcher(inputStr); if(matcher.matches()){ isValid = true; } return isValid; } Hi sorry, yes this is homework. For this assignments the only valid format are xxx-xxx-xxxx and xxx-xxxx, all other formats (xxx)xxx-xxxx or xxxxxxxxxx are invalid in this case. I would like to know if my regular expression is correct

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  • How do I set up the python/c library correctly?

    - by Bartvbl
    I have been trying to get the python/c library to like my mingW compiler. The python online doncumentation; http://docs.python.org/c-api/intro.html#include-files only mentions that I need to import the python.h file. I grabbed it from the installation directory (as is required on the windows platform), and tested it by compiling the script: #include "Python.h". This compiled fine. Next, I tried out the snippet of code shown a bit lower on the python/c API page: PyObject *t; t = PyTuple_New(3); PyTuple_SetItem(t, 0, PyInt_FromLong(1L)); PyTuple_SetItem(t, 1, PyInt_FromLong(2L)); PyTuple_SetItem(t, 2, PyString_FromString("three")); For some reason, the compiler would compile the code if I'd remove the last 4 lines (so that only the pyObject variable definition would be left), yet calling the actual constructor of the tuple returned errors. I am probably missing something completely obvious here, given I am very new to C, but does anyone know what it is?

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  • How to define template directives (from an API perspective)?

    - by Ralph
    Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

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  • Guru of the Week 2 no match for the operator==

    - by Adam
    From Guru of the Week 2. We have the function: string FindAddr(const list<Employee> l, string name) { for( list<Employee>::const_iterator i = l.begin(); i != l.end(); i++) { if( *i == name ) // here will be compilation error { return (*i).addr; } } return ""; } I added dummy Employee class to that: class Employee { string n; public: string addr; Employee(string name) : n(name) {} Employee() {} string name() const { return n; } operator string() { return n; } }; And got compilation error: error: no match for ‘operator==’ in ‘i.std::_List_iterator<_Tp>::operator* [with _Tp = Employee]() == name’ It works only if add operator== to Employee. But, Herb Sutter wrote that: The Employee class isn't shown, but for this to work it must either have a conversion to string or a conversion ctor taking a string. But Employee has a conversion function and conversion constructor as well. GCC version 4.4.3. Compiled normally, g++ file.cpp without any flags. There should be implicit conversion and it should work, why it doesn't?

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  • How to retrieve data from a dialog box?

    - by Ralph
    Just trying to figure out an easy way to either pass or share some data between the main window and a dialog box. I've got a collection of variables in my main window that I want to pass to a dialog box so that they can be edited. They way I've done it now, is I pass in the list to the constructor of the dialog box: private void Button_Click(object sender, RoutedEventArgs e) { var window = new VariablesWindow(_templateVariables); window.Owner = this; window.ShowDialog(); if(window.DialogResult == true) _templateVariables = new List<Variable>(window.Variables); } And then in there, I guess I need to deep-copy the list, public partial class VariablesWindow : Window { public ObservableCollection<Variable> Variables { get; set; } public VariablesWindow(IEnumerable<Variable> vars) { Variables = new ObservableCollection<Variable>(vars); // ... So that when they're edited, it doesn't get reflected back in the main window until the user actually hits "Save". Is that the correct approach? If so, is there an easy way to deep-copy an ObservableCollection? Because as it stands now, I think my Variables are being modified because it's only doing a shallow-copy.

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  • passing reference of class to another class android error

    - by prolink007
    I recently asked the precursor to this question and had a great reply. However, when i was working this into my android application i am getting an unexpected error and was wondering if everyone could take a look at my code and help me see what i am doing wrong. Link to the initial question: passing reference of class to another class My ERROR: "The constructor ConnectDevice(new View.OnClickListener(){}) is undefined" The above is an error detected by eclipse. Thanks in advance! Below are My code snippets: public class SmartApp extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.intro); final Button connectDeviceButton = (Button) findViewById(R.id.connectDeviceButton); connectDeviceButton.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { Thread cThread = new Thread(new ConnectDevice(this)); cThread.start(); } }); } } public class ConnectDevice implements Runnable { private boolean connected; private SmartApp smartAppRef; private ObjectInputStream ois; public ConnectDevice(SmartApp smartAppRef) { this.smartAppRef = smartAppRef; } }

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  • How can I theme custom form(drupal 6.x)

    - by Andrew
    DRUPAL 6.X I have this custom form constructor inside my custom module which is invoke through ajax request. I’m attempting to theme this form with the template file reside in my theme directory. For that matter, I’ve registered my theme inside template.php file which reside in my theme folder. Here’s how this file looks – function my_theme() { return array( 'searchdb' => array( 'arguments' => array('form' => NULL), 'template' => 'searchform', ) ); } And the following is the excerpt of module code – function test_menu() { $my_form['searchdb'] = array( 'title' => 'Search db', 'page callback' => 'get_form', 'page arguments' => array(0), 'access arguments' => array('access content'), 'type' => MENU_CALLBACK, ); return $my_form; } function get_form($formtype){ switch($formtype){ case 'searchdb' : echo drupal_get_form('searchdb'); break; } } function searchdb(){ $form['customer_name'] = array( '#type' => 'textfield', '#title' => t('Customer Name'), '#size' => 50, '#attributes' => array('class' => 'name-textbox'), ); return $form; } As you can imagine, this is not working at all. Just to test if my theme is even registered, I’ve also tested with theme function but, it’s not called. I've checked template file name and form-id(through the outputted html source) and everything seems ok. I would be glad if anyone could point me to the right direction.

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  • Porting Symbian C++ to Android NDK

    - by Donal Rafferty
    I've been given some Symbian C++ code to port over for use with the Android NDK. The code has lots of Symbian specific code in it and I have very little experience of C++ so its not going very well. The main thing that is slowing me down is trying to figure out the alternatives to use in normal C++ for the Symbian specific code. At the minute the compiler is throwing out all sorts of errors for unrecognised types. From my recent research these are the types that I believe are Symbian specific: TInt, TBool, TDesc8, RSocket, TInetAddress, TBuf, HBufc, RPointerArray Changing TInt and TBool to int and bool respectively works in the compiler but I am unsure what to use for the other types? Can anyone help me out with them? Especially TDesc, TBuf, HBuf. Also Symbian has a two phase contructor using NewL and NewLc But would changing this to a normal C++ constructor be ok? Finally Symbian uses the clean up stack to help eliminate memory leaks I believe, would removing the clean up stack code be acceptable, I presume it should be replaced with try/catch statements?

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  • Passing functor and function pointers interchangeably using a templated method in C++

    - by metroxylon
    I currently have a templated class, with a templated method. Works great with functors, but having trouble compiling for functions. Foo.h template <typename T> class Foo { public: // Constructor, destructor, etc... template <typename Func> void bar(T x, Func f); }; template <typename T> template <typename Func> Foo::bar(T x, Func f) { /* some code here */ } Main.cpp #include "Foo.h" template <typename T> class Functor { public: Functor() {} void operator()(T x) { /* ... */ } private: /* some attributes here */ }; void Function(T x) { /* ... */ } int main() { Foo<int> foo; foo.bar(2, Functor); // No problem foo.bar(2, Function); // <unresolved overloaded function type> return 0; }

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  • dynamic inheritance without touching classes

    - by Jasper
    I feel like the answer to this question is really simple, but I really am having trouble finding it. So here goes: Suppose you have the following classes: class Base; class Child : public Base; class Displayer { public: Displayer(Base* element); Displayer(Child* element); } Additionally, I have a Base* object which might point to either an instance of the class Base or an instance of the class Child. Now I want to create a Displayer based on the element pointed to by object, however, I want to pick the right version of the constructor. As I currently have it, this would accomplish just that (I am being a bit fuzzy with my C++ here, but I think this the clearest way) object->createDisplayer(); virtual void Base::createDisplayer() { new Displayer(this); } virtual void Child::createDisplayer() { new Displayer(this); } This works, however, there is a problem with this: Base and Child are part of the application system, while Displayer is part of the GUI system. I want to build the GUI system independently of the Application system, so that it is easy to replace the GUI. This means that Base and Child should not know about Displayer. However, I do not know how I can achieve this without letting the Application classes know about the GUI. Am I missing something very obvious or am I trying something that is not possible?

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  • Can a custom MFC window/dialog be a template class?

    - by John
    There's a bunch of special macros that MFC uses when creating dialogs, and in my quick tests I'm getting weird errors trying to compile a template dialog class. Is this likely to be a big pain to achieve? Here's what I tried: MyDlg.h template <class W> class CMyDlg : public CDialog { typedef CDialog super; DECLARE_DYNAMIC(CMyDlg <W>) public: CMyDlg (CWnd* pParent); // standard constructor virtual ~CMyDlg (); // Dialog Data enum { IDD = IDD_MYDLG }; protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support DECLARE_MESSAGE_MAP() private: W *m_pWidget; //W will always be a CDialog }; IMPLEMENT_DYNAMIC(CMyDlg<W>, super) <------------------- template <class W> CMyDlg<W>::CMyDlg(CWnd* pParent) : super(CMyDlg::IDD, pParent) { m_pWidget = new W(this); } I get a whole bunch of errors but main one appears to be: error C2955: 'CMyDlg' : use of class template requires template argument list I tried using some specialised template versions of macros but it doesn't help much, other errors change but this one remains. Note my code is all in one file, since C++ templates don't like .h/.cpp like normal.

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  • How to throw meaningful data in exceptions ?

    - by ZeroCool
    I would like to throw exceptions with meaningful explanation ! I thought of using variable arguments worked fine but lately I figured out it's impossible to extend the class in order to implement other exception types. So I figured out using an std::ostreamstring as a an internal buffer to deal with formatting ... but doesn't compile! I guess it has something to deal with copy constructors. Anyhow here is my piece of code: class Exception: public std::exception { public: Exception(const char *fmt, ...); Exception(const char *fname, const char *funcname, int line, const char *fmt, ...); //std::ostringstream &Get() { return os_ ; } ~Exception() throw(); virtual const char *what() const throw(); protected: char err_msg_[ERRBUFSIZ]; //std::ostringstream os_; }; The variable argumens constructor can't be inherited from! this is why I thought of std::ostringstream! Any advice on how to implement such approach ?

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  • Delphi: EInvalidOp in neural network class (TD-lambda)

    - by user89818
    I have the following draft for a neural network class. This neural network should learn with TD-lambda. It is started by calling the getRating() function. But unfortunately, there is an EInvalidOp (invalid floading point operation) error after about 1000 iterations in the following lines: neuronsHidden[j] := neuronsHidden[j]+neuronsInput[t][i]*weightsInput[i][j]; // input -> hidden weightsHidden[j][k] := weightsHidden[j][k]+LEARNING_RATE_HIDDEN*tdError[k]*eligibilityTraceOutput[j][k]; // adjust hidden->output weights according to TD-lambda Why is this error? I can't find the mistake in my code :( Can you help me? Thank you very much in advance! unit uNeuronalesNetz; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, StdCtrls, Grids, Menus, Math; const NEURONS_INPUT = 43; // number of neurons in the input layer NEURONS_HIDDEN = 60; // number of neurons in the hidden layer NEURONS_OUTPUT = 1; // number of neurons in the output layer NEURONS_TOTAL = NEURONS_INPUT+NEURONS_HIDDEN+NEURONS_OUTPUT; // total number of neurons in the network MAX_TIMESTEPS = 42; // maximum number of timesteps possible (after 42 moves: board is full) LEARNING_RATE_INPUT = 0.25; // in ideal case: decrease gradually in course of training LEARNING_RATE_HIDDEN = 0.15; // in ideal case: decrease gradually in course of training GAMMA = 0.9; LAMBDA = 0.7; // decay parameter for eligibility traces type TFeatureVector = Array[1..43] of SmallInt; // definition of the array type TFeatureVector TArtificialNeuralNetwork = class // definition of the class TArtificialNeuralNetwork private // GENERAL SETTINGS START learningMode: Boolean; // does the network learn and change its weights? // GENERAL SETTINGS END // NETWORK CONFIGURATION START neuronsInput: Array[1..MAX_TIMESTEPS] of Array[1..NEURONS_INPUT] of Extended; // array of all input neurons (their values) for every timestep neuronsHidden: Array[1..NEURONS_HIDDEN] of Extended; // array of all hidden neurons (their values) neuronsOutput: Array[1..NEURONS_OUTPUT] of Extended; // array of output neurons (their values) weightsInput: Array[1..NEURONS_INPUT] of Array[1..NEURONS_HIDDEN] of Extended; // array of weights: input->hidden weightsHidden: Array[1..NEURONS_HIDDEN] of Array[1..NEURONS_OUTPUT] of Extended; // array of weights: hidden->output // NETWORK CONFIGURATION END // LEARNING SETTINGS START outputBefore: Array[1..NEURONS_OUTPUT] of Extended; // the network's output value in the last timestep (the one before) eligibilityTraceHidden: Array[1..NEURONS_INPUT] of Array[1..NEURONS_HIDDEN] of Array[1..NEURONS_OUTPUT] of Extended; // array of eligibility traces: hidden layer eligibilityTraceOutput: Array[1..NEURONS_TOTAL] of Array[1..NEURONS_TOTAL] of Extended; // array of eligibility traces: output layer reward: Array[1..MAX_TIMESTEPS] of Array[1..NEURONS_OUTPUT] of Extended; // the reward value for all output neurons in every timestep tdError: Array[1..NEURONS_OUTPUT] of Extended; // the network's error value for every single output neuron t: Byte; // current timestep cyclesTrained: Integer; // number of cycles trained so far (learning rates could be decreased accordingly) last50errors: Array[1..50] of Extended; // LEARNING SETTINGS END public constructor Create; // create the network object and do the initialization procedure UpdateEligibilityTraces; // update the eligibility traces for the hidden and output layer procedure tdLearning; // learning algorithm: adjust the network's weights procedure ForwardPropagation; // propagate the input values through the network to the output layer function getRating(state: TFeatureVector; explorative: Boolean): Extended; // get the rating for a given state (feature vector) function HyperbolicTangent(x: Extended): Extended; // calculate the hyperbolic tangent [-1;1] procedure StartNewCycle; // start a new cycle with everything set to default except for the weights procedure setLearningMode(activated: Boolean=TRUE); // switch the learning mode on/off procedure setInputs(state: TFeatureVector); // transfer the given feature vector to the input layer (set input neurons' values) procedure setReward(currentReward: SmallInt); // set the reward for the current timestep (with learning then or without) procedure nextTimeStep; // increase timestep t function getCyclesTrained(): Integer; // get the number of cycles trained so far procedure Visualize(imgHidden: Pointer); // visualize the neural network's hidden layer end; implementation procedure TArtificialNeuralNetwork.UpdateEligibilityTraces; var i, j, k: Integer; begin // how worthy is a weight to be adjusted? for j := 1 to NEURONS_HIDDEN do begin for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceOutput[j][k] := LAMBDA*eligibilityTraceOutput[j][k]+(neuronsOutput[k]*(1-neuronsOutput[k]))*neuronsHidden[j]; for i := 1 to NEURONS_INPUT do begin eligibilityTraceHidden[i][j][k] := LAMBDA*eligibilityTraceHidden[i][j][k]+(neuronsOutput[k]*(1-neuronsOutput[k]))*weightsHidden[j][k]*neuronsHidden[j]*(1-neuronsHidden[j])*neuronsInput[t][i]; end; end; end; end; procedure TArtificialNeuralNetwork.setReward; VAR i: Integer; begin for i := 1 to NEURONS_OUTPUT do begin // +1 = player A wins // 0 = draw // -1 = player B wins reward[t][i] := currentReward; end; end; procedure TArtificialNeuralNetwork.tdLearning; var i, j, k: Integer; begin if learningMode then begin for k := 1 to NEURONS_OUTPUT do begin if reward[t][k] = 0 then begin tdError[k] := GAMMA*neuronsOutput[k]-outputBefore[k]; // network's error value when reward is 0 end else begin tdError[k] := reward[t][k]-outputBefore[k]; // network's error value in the final state (reward received) end; for j := 1 to NEURONS_HIDDEN do begin weightsHidden[j][k] := weightsHidden[j][k]+LEARNING_RATE_HIDDEN*tdError[k]*eligibilityTraceOutput[j][k]; // adjust hidden->output weights according to TD-lambda for i := 1 to NEURONS_INPUT do begin weightsInput[i][j] := weightsInput[i][j]+LEARNING_RATE_INPUT*tdError[k]*eligibilityTraceHidden[i][j][k]; // adjust input->hidden weights according to TD-lambda end; end; end; end; end; procedure TArtificialNeuralNetwork.ForwardPropagation; var i, j, k: Integer; begin for j := 1 to NEURONS_HIDDEN do begin neuronsHidden[j] := 0; for i := 1 to NEURONS_INPUT do begin neuronsHidden[j] := neuronsHidden[j]+neuronsInput[t][i]*weightsInput[i][j]; // input -> hidden end; neuronsHidden[j] := HyperbolicTangent(neuronsHidden[j]); // activation of hidden neuron j end; for k := 1 to NEURONS_OUTPUT do begin neuronsOutput[k] := 0; for j := 1 to NEURONS_HIDDEN do begin neuronsOutput[k] := neuronsOutput[k]+neuronsHidden[j]*weightsHidden[j][k]; // hidden -> output end; neuronsOutput[k] := HyperbolicTangent(neuronsOutput[k]); // activation of output neuron k end; end; procedure TArtificialNeuralNetwork.setLearningMode; begin learningMode := activated; end; constructor TArtificialNeuralNetwork.Create; var i, j, k: Integer; begin inherited Create; Randomize; // initialize random numbers generator learningMode := TRUE; cyclesTrained := -2; // only set to -2 because it will be increased twice in the beginning StartNewCycle; for j := 1 to NEURONS_HIDDEN do begin for k := 1 to NEURONS_OUTPUT do begin weightsHidden[j][k] := abs(Random-0.5); // initialize weights: 0 <= random < 0.5 end; for i := 1 to NEURONS_INPUT do begin weightsInput[i][j] := abs(Random-0.5); // initialize weights: 0 <= random < 0.5 end; end; for i := 1 to 50 do begin last50errors[i] := 0; end; end; procedure TArtificialNeuralNetwork.nextTimeStep; begin t := t+1; end; procedure TArtificialNeuralNetwork.StartNewCycle; var i, j, k, m: Integer; begin t := 1; // start in timestep 1 cyclesTrained := cyclesTrained+1; // increase the number of cycles trained so far for j := 1 to NEURONS_HIDDEN do begin neuronsHidden[j] := 0; for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceOutput[j][k] := 0; outputBefore[k] := 0; neuronsOutput[k] := 0; for m := 1 to MAX_TIMESTEPS do begin reward[m][k] := 0; end; end; for i := 1 to NEURONS_INPUT do begin for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceHidden[i][j][k] := 0; end; end; end; end; function TArtificialNeuralNetwork.getCyclesTrained; begin result := cyclesTrained; end; procedure TArtificialNeuralNetwork.setInputs; var k: Integer; begin for k := 1 to NEURONS_INPUT do begin neuronsInput[t][k] := state[k]; end; end; function TArtificialNeuralNetwork.getRating; begin setInputs(state); ForwardPropagation; result := neuronsOutput[1]; if not explorative then begin tdLearning; // adjust the weights according to TD-lambda ForwardPropagation; // calculate the network's output again outputBefore[1] := neuronsOutput[1]; // set outputBefore which will then be used in the next timestep UpdateEligibilityTraces; // update the eligibility traces for the next timestep nextTimeStep; // go to the next timestep end; end; function TArtificialNeuralNetwork.HyperbolicTangent; begin if x > 5500 then // prevent overflow result := 1 else result := (Exp(2*x)-1)/(Exp(2*x)+1); end; end.

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