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  • Confusion about pointers and their memory addresses

    - by TimothyTech
    alright, im looking at a code here and the idea is difficult to understand. #include <iostream> using namespace std; class Point { public : int X,Y; Point() : X(0), Y(0) {} }; void MoveUp (Point * p) { p -> Y += 5; } int main() { Point point MoveUp(&point) cout <<point.X << point.Y; return 0; } Alright, so i believe that a class is created and X and Y are declared and they are put inside a constructor a method is created and the argument is Point * p, which means that we are going to stick the constructor's pointer inside the function; now we create an object called point then call our method and put the pointers address inside it? isnt the pointers address just a memory number like 0x255255? and why wasnt p ever declared? (int * p = Y) what is a memory addres exactly? that it can be used as an argument?

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  • Safe way for getting/finding a vertex in a graph with custom properties -> good programming practice

    - by Shadow
    Hi, I am writing a Graph-class using boost-graph-library. I use custom vertex and edge properties and a map to store/find the vertices/edges for a given property. I'm satisfied with how it works, so far. However, I have a small problem, where I'm not sure how to solve it "nicely". The class provides a method Vertex getVertex(Vertexproperties v_prop) and a method bool hasVertex(Vertexproperties v_prop) The question now is, would you judge this as good programming practice in C++? My opinion is, that I have first to check if something is available before I can get it. So, before getting a vertex with a desired property, one has to check if hasVertex() would return true for those properties. However, I would like to make getVertex() a bit more robust. ATM it will segfault when one would directly call getVertex() without prior checking if the graph has a corresponding vertex. A first idea was to return a NULL-pointer or a pointer that points past the last stored vertex. For the latter, I haven't found out how to do this. But even with this "robust" version, one would have to check for correctness after getting a vertex or one would also run into a SegFault when dereferencing that vertex-pointer for example. Therefore I am wondering if it is "ok" to let getVertex() SegFault if one does not check for availability beforehand?

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  • C++ Instantiate class and add name to array/vector then cycle through update functions from the array

    - by SD42
    I have a bunch of classes in a basic (and badly coded!) game engine that are currently instantiated in the code and have to have their individual update functions called. What I want to do is be able to create an instance of a class, pass the name to an array, and then subsequently cycle through the array to call the update functions of each class. I'm unsure as to whether or not this is an impossible or spectacularly stupid way of trying to manage objects, so please tell me if it is. So currently I might have manually instantiated Enemy class a couple of times: Enemy enem1; Enemy enem2; I then have to update them manually in the game loop: enem1.update(); enem2.update(); What method should I use to be able to spawn and destroy instances of the enemy class during gametime? Is it possible to populate an array with instantiated names and then do something like (and i'm aware this doesn't work); array[x].update(); Then iterate through the names in the array? Anything that even points me in the right direction would be greatly appreciated!

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  • Add a smaller subView with new origin

    - by ReachWest
    I can't get my head around this - I know it must be simple.. I'm starting to feel pretty stupid. I have two viewControllers. MainViewController.h/m and LevelsViewController.h/m I want to add a subView from the LevelsViewController class and a view that is built in IB called levelsView. I am calling this from the MainViewController.m file. The levelsView is only 200x200 pixels and I want to offset it from the frame origin of the superView by x=140 pixels and y=50 pixels. I have this working - the view displays, but I can't figure out how to offset it. It only shows up at the 0,0 superView frame origin. (The superView shows below it, which is what I want). Here is the code I call in the method in the MainViewController.m that displays the levelsView.(I have commented out some of the things I have tried - but throws this error: error: request for member 'frame' in 'myLevelsView', which is of non-class type 'LevelsViewController*' ) - (void) displayLevelsPage { if (self.theLevelsView == nil) // Does not yet exist - therefore create { LevelsViewController * myLevelsView = [[LevelsViewController alloc] initWithNibName:@"levelsView" bundle:[NSBundle mainBundle]]; NSLog(@"NEW theLevelsView instance created!"); CGRect frame2 = CGRectMake(140, 50, 200, 200); //myLevelsView.frame = frame2; self.theLevelsView = myLevelsView; [myLevelsView release]; } [self.view addSubview: theLevelsView.view]; NSLog(@"Levels View has been activated"); } Any insight would be appreciated.

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  • check if foler exists in the root jquery

    - by Dimal Chandrasiri
    I'm trying to load an image to a div background using the following file structure in the root. WebContent -- | zharaimages -- | [ItemID] -- | Image.jpg This is done by jQuery and the file structure is inside the root. The ItemID folder is dynamic and I have to check whether the path exists using jQuery and if the path is not valid, I should go to a default path to fetch the default image. How can I check the path is valid using jQuery. I'm hoping to this can be done without an ajax call. Can any one help me on a tutorial or an API I can use for this! UPDATE The files are on the server. The concept I have is that I have 100s of item elements & I want to load an image for each item element. The images are saved in the server ( a local host ) and the folder hierarchy is divided using the item ID as shown. What I want to do is check whether the image file exists before appending it to the background of the item element div. Is this possible. This is a web application developed using spring.

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  • Using Gtk.TreeDragSource.drag_data_get()

    - by knutsondc
    I have a simple Gtk.TreeView with a Gtk.ListStore with four columns as the model. I want to be able to drag and drop rows within the TreeView and track row insertions, changes and deletions as they happen so I can implement undo/redo to drag and drop operations. I'm using PyGObject 3 and Python 3.2. I thought that using methods under the Gtk.TreeDragSource and Gtk.TreeDragDest interfaces would suit my needs perfectly, with Gtk.TreeDragSource.drag_data_get() in my drag_data_get handler and Gtk.TreeDragDest.drag_data_received() or Gtk.tree_get_row_drag_data() in my drag_data_received handler. Basically, what I've tried looks something like this: def drag_data_received(self, treeview, context, x, y, selection, info, time): treeselection = tv.get_selection() model, my_iter = treeselection.get_selected() path = model.get_path(my_iter) result = Gtk.TreeDragSource.drag_data_get(path, selection) def drag_data_received(self, tv, context, x, y, selection, info, time): result, model, row = Gtk.tree_get_row_drag_data(selection) my_iter = model.get_iter(row) data = [model.get_value(my_iter, i) for i in range(model.get_n_columns())] drop_info = tv.get_dest_row_at_pos(x, y) if drop_info: path, position = drop_info my_iter = model.get_iter(path) if (position == Gtk.TreeViewDropPosition.BEFORE or position == Gtk.TreeViewDropPosition.INTO_OR_BEFORE): model.insert_before(my_iter, [data]) else: model.insert_after(my_iter, [data]) else: model.append([data]) if context.get_actions() == Gdk.DragAction.MOVE|Gdk.DragAction.DEFAULT: context.finish(True, True, time) return This fails spectacularly - when Python hits the call to Gtk.TreeDragSource.drag_data_get(), Python crashes and my program window swiftly disappears. I don't even get to the drag_data_received handler. Can anyone point me to some example code showing how these methods using the TreeDragSource and TreeDragDest interfaces work? Any help much appreciated!

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  • Sending a message to nil?

    - by Ryan Delucchi
    As a Java developer who is reading Apple's Objective-C 2.0 documentation: I wonder as to what sending a message to nil means - let alone how it is actually useful. Taking an excerpt from the documentation: There are several patterns in Cocoa that take advantage of this fact. The value returned from a message to nil may also be valid: If the method returns an object, any pointer type, any integer scalar of size less than or equal to sizeof(void*), a float, a double, a long double, or a long long, then a message sent to nil returns 0. If the method returns a struct, as defined by the Mac OS X ABI Function Call Guide to be returned in registers, then a message sent to nil returns 0.0 for every field in the data structure. Other struct data types will not be filled with zeros. If the method returns anything other than the aforementioned value types the return value of a message sent to nil is undefined. Has Java rendered my brain incapable of grokking the explanation above? Or is there something that I am missing that would make this as clear as glass? Note: Yes, I do get the idea of messages/receivers in Objective-C, I am simply confused about a receiver that happens to be nil.

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  • Action on each method's return value

    - by RobGlynn
    What I'd like to do is take some action using the value returned by every method in a class. So for instance, if I have a class Order which has a method public Customer GetCustomer() { Customer CustomerInstance = // get customer return CustomerInstance; } Let's say I want to log the creation of these - Log(CustomerInstance); My options (AFAIK) are: Call Log() in each of these methods before returning the object. I'm not a fan of this because it gets unwieldy if used on a lot of classes with a lot of methods. It also is not an intrinsic part of the method's purpose. Use composition or inheritance to layer the log callon the Order class similar to: public Customer GetCustomer() { Customer CustomerInstance = this.originalCustomer.GetCustomer(); Log(CustomerInstance); return CustomerInstance; } I don't think this buys me anything over #1. Create extension methods on each of the returned types: Customer CustomerInstance = Order.GetCustomer().Log(); which has just as many downsides. I'm looking to do this for every (or almost every) object returned, automatically if possible, without having to write double the amount of code. I feel like I'm either trying to bend the language into doing something it's not supposed to, or failing to recognize some language feature that would enable this. Possible solutions would be greatly appreciated.

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  • Should I re-use UI elements across view controllers?

    - by Endemic
    In the iPhone app I'm currently working on, I'd like two navigation controllers (I'll call them A and B) to have toolbars that are identical in appearance and function. The toolbar in question will look like this: [(button) (flexible-space) (label)] For posterity's sake, the label is actually a UIBarButtonItem with a custom view. My design requires that A always appear directly before B on the navigation stack, so B will never be loaded without A having been loaded. Given this layout, I started wondering, "Is it worth it to re-use A's toolbar items in B's toolbar?" As I see it, my options are: 1. Don't worry about re-use, create the toolbar items twice 2. Create the toolbar items in A and pass them to B in a custom initializer 3. Use some more obscure method that I haven't thought of to hold the toolbar constant when pushing a view controller As far as I can see, option 1 may violate DRY, but guarantees that there won't be any confusion on the off chance that (for example) the button may be required to perform two different (no matter how similar) functions for either view controller in future versions of the app. Were that to happen, options 2 or 3 would require the target-action of the button to change when B is loaded and unloaded. Even if the button were never required to perform different functions, I'm not sure what its proper target would be under option 2. All in all, it's not a huge problem, even if I have to go with option 1. I'm probably overthinking this anyway, trying to apply the dependency injection pattern where it's not appropriate. I just want to know the best practice should this situation arise in a more extreme form, like if a long chain of view controllers need to use identical (in appearance and function) UI elements.

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  • Why is post() not updating the DOM after it returns? Wierd timing problem observed.

    - by Sephrial
    Hi all, I have the following code that is really bugging me, I'm thinking perhaps the post() function needs to be blocking. I am new to jQuery(latest version) and AJAX, but I'm using ColdFusion which returns some HTML in the data variable. var dataResult; var statusResult; $.post('fh_result.cfm',$('#myform').serialize(),function(data,status){ dataResult = data; statusResult = status; }); //alert(statusResult); if ('success' == statusResult) { alert(statusResult); $('#result').html(dataResult); } When I uncomment out the first alert, it returns 'undefined' but then it goes into the if block and the next alert box it says 'success'. If I comment out that line it doesn't make it into the if statement at all. My guess is that I want to make this a blocking call or something because I want to insert the data on the page after the post. I also have a problem when I re-write the top code as follows: var dataResult; var statusResult; $.post('fh_result.cfm',$('#myform').serialize(),function(data,status){ dataResult = data; statusResult = status; alert(statusResult); $('#result').html(dataResult); }); //alert(statusResult); Now in this case, the alert says 'success' when I comment out the second alert box. When I uncomment it out, I get one alert that says success and the other that says undefined, but this time it updates the DOM with the result of the postback as desired. How can I do this without the alert box?

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  • Calling a method from another view in objective-c. (iphone sdk).

    - by MarcZero
    Hello. I am currently creating a multi-view game on the iPhone platform. I have my main view start to play some background music upon loading. I then go to another view and start the game. I am trying to get the background music from the original view to stop once I start the game. I am having trouble getting the stop playing music message to my original view. Here is the relevant info: The main view where the sound is played from is just a subView of the programViewController class called *viewController. The heading is in the programAppDelegate class. The sound is done using the AVAudioPlayer class and plays fine when the program starts up and when I navigate to other subviews that are added on by going through the menu system. In the view that I want to start the game, I attempt to call the instance of the class to turn of the player but anytime I use this format of code: [viewController #######]; It gives a build error of "viewController undeclared" no matter what I put after the "viewController" in the message.I have attempted to import the programAppDelegate.h file but it still gives the same error. I realize this might be a simple misunderstanding of the objective-c language but I cannot find any info on this issue. I am a recent convert from Java so I am trying to wrap my head around everything. Thank you for your time!

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  • C# Reflection StackTrack get value

    - by John
    I'm making pretty heavy use of reflection in my current project to greatly simplify communication between my controllers and the wcf services. What I want to do now is to obtain a value from the Session within an object that has no direct access to HttpSessionStateBase (IE: Not a controller). For example, a ViewModel. I could pass it in or pass a reference to it etc. but that is not optimal in my situation. Since everything comes from a Controller at some point in my scenario I can do the following to walk the sack to the controller where the call originated, pretty simple stuff: var trace = new System.Diagnostics.StackTrace(); foreach (var frame in trace.GetFrames()) { var type = frame.GetMethod().DeclaringType; var prop = type.GetProperty("Session"); if(prop != null) { // not sure about this part... var value = prop.GetValue(type, null); break; } } The trouble here is that I can't seem to work out how to get the "instance" of the controller or the Session property so that I can read from it.

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  • Pass Element value to $ajax->link in cakephp

    - by TwoThumbs
    I need to pass the value of an element to an $ajax-link without using a form/submit structure. (because I have a dynamically set number of clickable links through which I am triggering the action) I used to do this in Ruby using the Prototype javascript function $F like this: <%= link_to_remote "#{item.to_s}", :url => { :action => :add_mpc }, :with => "'category=' + $F('mpc_category')" -%> But this does not seem to work in Cakephp: <?php echo $ajax->link(substr($vehicle['vehicles']['year'], -2), array('action' => 'add_mpc', 'category' => '$F("mpc_category")'), array('update' => 'results', 'position' => 'top')); ?> PHP sees $F as a variable instead of a call to javascript. I'm not too familiar with Javascript, but is there another way to pass the value of the 'mpc_category' input element to the controller through this link? I have been looking for a couple days and can't find anyone dealing with this specific issue. Thanks for any assistance. Edit: fixed syntax in php statement.

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  • PHP - Use isset inside function not working..?

    - by pnichols
    I have a PHP script that when loaded, check first if it was loaded via a POST, if not if GET['id'] is a number. Now I know I could do this like this: if(isset($_GET['id']) AND isNum($_GET['id'])) { ... } function isNum($data) { $data = sanitize($data); if ( ctype_digit($data) ) { return true; } else { return false; } } But I would like to do it this way: if(isNum($_GET['id'])) { ... } function isNum($data) { if ( isset($data) ) { $data = sanitize($data); if ( ctype_digit($data) ) { return true; } else { return false; } } else { return false; } } When I try it this way, if $_GET['id'] isn't set, I get a warning of undefined index: id... It's like as soon as I put my $_GET['id'] within my function call, it sends a warning... Even though my function will check if that var is set or not... Is there another way to do what I want to do, or am I forced to always check isset then add my other requirements..??

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  • Rails using plural table names even though I told it to use singular

    - by Jason Swett
    I tried to run rake test:profile and I got this error: ... Table 'mcif2.accounts' doesn't exist: DELETE FROM `accounts` I know accounts doesn't exist. It's called account. I know Rails uses plural table names by default but here's what my config/environment.rb looks like: # Load the rails application require File.expand_path('../application', __FILE__) # Initialize the rails application McifRails::Application.initialize! ActiveRecord::Base.pluralize_table_names = false And here's what db/schema.rb looks like: ActiveRecord::Schema.define(:version => 0) do create_table "account", :force => true do |t| t.integer "customer_id", :limit => 8, :null => false t.string "account_number", :null => false t.integer "account_type_id", :limit => 8 t.date "open_date", :null => false So I don't understand why Rails still wants to call it accounts sometimes. Any ideas? If it helps give any clues at all, here are the results of grep -ir 'accounts' *.

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  • C++ const-reference semantics?

    - by Kristoffer
    Consider the sample application below. It demonstrates what I would call a flawed class design. #include <iostream> using namespace std; struct B { B() : m_value(1) {} long m_value; }; struct A { const B& GetB() const { return m_B; } void Foo(const B &b) { // assert(this != &b); m_B.m_value += b.m_value; m_B.m_value += b.m_value; } protected: B m_B; }; int main(int argc, char* argv[]) { A a; cout << "Original value: " << a.GetB().m_value << endl; cout << "Expected value: 3" << endl; a.Foo(a.GetB()); cout << "Actual value: " << a.GetB().m_value << endl; return 0; } Output: Original value: 1 Expected value: 3 Actual value: 4 Obviously, the programmer is fooled by the constness of b. By mistake b points to this, which yields the undesired behavior. My question: What const-rules should you follow when designing getters/setters? My suggestion: Never return a reference to a member variable if it can be set by reference through a member function. Hence, either return by value or pass parameters by value. (Modern compilers will optimize away the extra copy anyway.)

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  • WPF Calling a custom command on a custom control (from a viewmodel?)

    - by user190615
    I want to take a snap of the visual tree of a custom wpf control when the user clicks a button in a toolbar. The control is bound to a viewmodel. I have a BitmapSource dp in the custom control holding the snapped image which is bound to a property on my VM. The BitmapSource dp on the control is updated via a custom command on the control. I've tied the toolbar button's command to call the controls command which updates the BitmapSource. Now the problem is the end result I want is when the user clicks the button, the control updates its image and then the vm offers to save this image. I cant wrap my mind around an mvvm way of doing this. One inelegant solution is that control fires an event after the image is updated which is routed to the viewmodel as a command(command behavior) but then if i want to do something else with the image on some other button click, all the commands bound to the events will fire. All thoughts appreciated. EDIT The command on the control is a RoutedCommand and the commands in my vm are Prism delegate commands.

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  • How do I conditionally compile C code snippets to my Perl module?

    - by mobrule
    I have a module that will target several different operating systems and configurations. Sometimes, some C code can make this module's task a little easier, so I have some C functions that I would like to bind the code. I don't have to bind the C functions -- I can't guarantee that the end-user even has a C compiler, for instance, and it's generally not a problem to failover gracefully to a pure Perl way of accomplishing the same thing -- but it would be nice if I could call the C functions from the Perl script. Still with me? Here's another tricky part. Just about all of the C code is system specific -- a function written for Windows won't compile on Linux and vice-versa, and the function that does a similar thing on Solaris will look totally different. #include <some/Windows/headerfile.h> int foo_for_Windows_c(int a,double b) { do_windows_stuff(); return 42; } #include <path/to/linux/headerfile.h> int foo_for_linux_c(int a,double b) { do_linux_stuff(7); return 42; } Furthermore, even for native code that targets the same system, it's possible that only some of them can be compiled on any particular configuration. #include <some/headerfile/that/might/not/even/exist.h> int bar_for_solaris_c(int a,double b) { call_solaris_library_that_might_be_installed_here(11); return 19; } But ideally we could still use the C functions that would compile with that configuration. So my questions are: how can I compile C functions conditionally (compile only the code that is appropriate for the current value of $^O)? how can I compile C functions individually (some functions might not compile, but we still want to use the ones that can)? can I do this at build-time (while the end-user is installing the module) or at run-time (with Inline::C, for example)? Which way is better? how would I tell which functions were successfully compiled and are available for use from Perl? All thoughts appreciated!

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  • php validate integer [updated]

    - by George Garchagudashvili
    Read B A: I'll give quick example: $a = "\n \t 34 3"; // string(9) $aint = intval($a); // int(34) var_dump($a == $aint); result: bool(true) call me noob but can you tell me why/how does these variables do pass equalization test? What I want to achieve is to check if '1989' equals 1989 would be true, but not any other case. ex: '1989 ' should not pass the test. Also I don't want to use regex. B: I need to validate if variable is integer, I've tried all the available built-in functions or helpful tips, but the only best solution would be regex which I don't want to use this time. also filter_var is not best because it also filters data, but I want to only validate it. 123 -123 '123' '-123' these inputs to be only true, false otherwise I've tried many different options: ctype_digit("-123"); // false - doesn't work is_int('123'); // false filter_var(' 123 ', FILTER_VALIDATE_INT) !== false; // true - doesn't work

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  • Windows File I/O Reading

    - by eyeanand
    Currently working on open/read images in VC++. Some examples i came across on the internet use Windows.h I/O routines like ReadFile...but there seems to be inconsistency in there declaration. Here's what i have got. //So i have this function to load file BYTE* LoadFile ( int* width, int* height, long* size, LPCWSTR bmpfile ) { BITMAPFILEHEADER bmpheader; BITMAPINFOHEADER bmpinfo; DWORD bytesread = 0; HANDLE file = CreateFile ( bmpfile , GENERIC_READ, FILE_SHARE_READ,NULL, OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, NULL ); if ( NULL == file ) return NULL; if ( ReadFile ( file, &bmpheader, sizeof ( BITMAPFILEHEADER ),&bytesread, NULL ) == false ) { CloseHandle ( file ); return NULL; } . . . return appropriate value; } Now the ReadFile API function is declared as follows in WinBase.h WINBASEAPI BOOL WINAPI ReadFile( In HANDLE hFile, Out LPVOID lpBuffer, In DWORD nNumberOfBytesToRead, _Out_opt_ LPDWORD lpNumberOfBytesRead, _Inout_opt_ LPOVERLAPPED lpOverlapped ); And in MSDN examples... They call this function like this. ReadFile(hFile, chBuffer, BUFSIZE, &dwBytesRead, NULL) Which expects that "bytesRead" is sort of out parameter. so it gives me number of bytes read. But in my code ..it is giving error message. 'ReadFile' : cannot convert parameter 4 from 'LPDWORD *' to 'LPDWORD' so i just initialized bytesRead to 0 and passed by value.( which is wrong..but just to check if it works ). then it gives this exception Unhandled exception at 0x774406ae in ImProc.exe: 0xC0000005: Access violation writing location 0x00000000. Kindly suggest . Kindly tell if any code i missed out....including while forming the question itself. Thanks.

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  • Dynamically changing layout

    - by LTMOD
    I have a 2 x 2 grid of buttons. Each row of 2 is wrapped in a horizontal linear layout. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="100dip"> <Button android:layout_weight=".5" android:id="@+id/btn1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_gravity="center_vertical|center_horizontal" android:padding="5dip" android:layout_margin="2dip"> </Button> <Button android:layout_weight=".5" android:id="@+id/btn2" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dip" android:layout_margin="2dip"> </Button> At times I want to show all 4 buttons, and other times, I show the top 2 only, and sometimes, I need to show 2 on top, and one on the bottom. I would like to center the bottom one, but can't seem to accomplish this. In my code, I call btn4.setVisibility(8); //8 = GONE, which makes my 4th button disappear, but then btn3 ends up filling the entire layout. What I would like it to do instead is center itself within the layout at its correct width / height. I'm a bit new to this, so any help is greatly appreciated. Thanks in advance!

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  • Overload the behavior of count() when called on certain objects

    - by Tom
    In PHP 5, you can use magic methods, overload some classes, etc. In C++, you can implement functions that exist is STL as long as the argument types are different. Is there a way to do this in PHP? An example of what I'd like to do is this: class a { function a() { $this->list = array("1", "2"); } } $blah = new a(); count($blah); I would like blah to return 2. IE count the values of a specific array in the class. So in C++, the way I would do this might look like this: int count(a varName) { return count(varName->list); } Basically, I am trying to simplify data calls for a large application so I can call do this: count($object); rather than count($object->list); The list is going to be potentially a list of objects so depending on how it's used, it could be really nasty statement if someone has to do it the current way: count($object->list[0]->list[0]->list); So, can I make something similar to this: function count(a $object) { count($object->list); } I know PHP's count accepts a mixed var, so I don't know if I can override an individual type.

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  • (iphone) How to access CGRect member variable inside c++ class?

    - by Eugene
    i have a c++ class with CGrect variable and i'm getting segfault when trying to access it. class Parent { //with some virtual functions/dtors }; class Child { public: void SetRect(CGRect rect) { mRect = rect; } CGRect GetRect() { return mRect; } int GetIndex() { return mIndex; } private: CGRect mRect; int mIndex; }; i'm doing CGRect rect = childPtr->GetRect(); from object c code and it segfaults. I printed *childPtr just before the call and rect looks fine with intended data value. int index = childPtr->GetIndex(); from same object c code(*.mm), works fine though. Any idea why I'm getting segfaults? Thank you edit - It's got something to do with virtual functions. (gdb) p singlePuzzlePiece-GetRect() Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_PROTECTION_FAILURE at address: 0x00000001 0x00000001 in ?? () Cannot access memory at address 0x1 The program being debugged was signaled while in a function called from GDB. GDB remains in the frame where the signal was received. To change this behavior use "set unwindonsignal on" Evaluation of the expression containing the function (at 0x1) will be abandoned. (gdb) Somehow, the function is not properly compiled?

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  • method works fine, until it is called in a function, then UnboundLocalError

    - by user1776100
    I define a method called dist, to calculate the distance between two points which I does it correctly when directly using the method. However, when I get a function to call it to calculate the distance between two points, I get UnboundLocalError: local variable 'minkowski_distance' referenced before assignment edit sorry, I just realised, this function does work. However I have another method calling it that doesn't. I put the last method at the bottom This is the method: class MinkowskiDistance(Distance): def __init__(self, dist_funct_name_str = 'Minkowski distance', p=2): self.p = p def dist(self, obj_a, obj_b): distance_to_power_p=0 p=self.p for i in range(len(obj_a)): distance_to_power_p += abs((obj_a[i]-obj_b[i]))**(p) minkowski_distance = (distance_to_power_p)**(1/p) return minkowski_distance and this is the function: (it basically splits the tuples x and y into their number and string components and calculates the distance between the numeric part of x and y and then the distance between the string parts, then adds them. def total_dist(x, y, p=2, q=2): jacard = QGramDistance(q=q) minkowski = MinkowskiDistance(p=p) x_num = [] x_str = [] y_num = [] y_str = [] #I am spliting each vector into its numerical parts and its string parts so that the distances #of each part can be found, then summed together. for i in range(len(x)): if type(x[i]) == float or type(x[i]) == int: x_num.append(x[i]) y_num.append(y[i]) else: x_str.append(x[i]) y_str.append(y[i]) num_dist = minkowski.dist(x_num,y_num) str_dist = I find using some more steps #I am simply adding the two types of distance to get the total distance: return num_dist + str_dist class NearestNeighbourClustering(Clustering): def __init__(self, data_file, clust_algo_name_str='', strip_header = "no", remove = -1): self.data_file= data_file self.header_strip = strip_header self.remove_column = remove def run_clustering(self, max_dist, p=2, q=2): K = {} #dictionary of clusters data_points = self.read_data_file() K[0]=[data_points[0]] k=0 #I added the first point in the data to the 0th cluster #k = number of clusters minus 1 n = len(data_points) for i in range(1,n): data_point_in_a_cluster = "no" for c in range(k+1): distances_from_i = [total_dist(data_points[i],K[c][j], p=p, q=q) for j in range(len(K[c]))] d = min(distances_from_i) if d <= max_dist: K[c].append(data_points[i]) data_point_in_a_cluster = "yes" if data_point_in_a_cluster == "no": k += 1 K[k]=[data_points[i]] return K

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  • Magic squares, recursive

    - by user310827
    Hi, my problem is, I'm trying to permute all posibilities for a 3x3 square and check if the combination is magic. I've added a tweak with (n%3==0) if statement that if the sum of numbers in row differs from 15 it breaks the creation of other two lines... but it doesn't work. Any suggestions? I call the function with Permute(1). public static class Global { //int[] j = new int[6]; public static int[] a= {0,0,0,0,0,0,0,0,0}; public static int[] b= {0,0,0,0,0,0,0,0,0}; public static int count = 0; } public static void Permute(int n) { int tmp=n-1; for (int i=0;i<9;i++){ if (Global.b[i]==0 ) { Global.b[i]=1; Global.a[n-1]=i+1; if ((n % 3) == 0) { if (Global.a[0+tmp]+Global.a[1+tmp]+Global.a[2+tmp] == 15) { if (n<9) { Permute(n+1); } else { isMagic(Global.a); } } else break; } else { Permute(n+1); } Global.b[i]=0; } } }

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