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  • How can I simply change a class variable from another class in ObjectiveC?

    - by Daniel
    I simply want to change a variable of an object from another class. I can compile without a problem, but my variable always is set to 'null'. I used the following code: Object.h: @interface Object : NSObject { //... NSString *color; //... } @property(nonatomic, retain) NSString* color; + (id)Object; - (void)setColor:(NSString*)col; - (NSString*)getColor; @end Object.m: +(id)Object{ return [[[Object alloc] init] autorelease]; } - (void)setColor:(NSString*)col { self.color = col; } - (NSString*)getColor { return self.color; } MyViewController.h #import "Object.h" @interface ClassesTestViewController : UIViewController { Object *myObject; UILabel *label1; } @property UILabel *label1; @property (assign) Object *myObject; @end MyViewController.m: #import "Object.h" @implementation MyViewController @synthesize myObject; - (void)viewDidLoad { [myObject setColor:@"red"]; NSLog(@"Color = %@", [myObject getColor]); [super viewDidLoad]; } The NSLog message is always Color = (null) I tried many different ways to solve this problem, but no success. Any help would be appreciated.

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  • Why is TRest in Tuple<T1... TRest> not constrained?

    - by Anthony Pegram
    In a Tuple, if you have more than 7 items, you can provide an 8th item that is another tuple and define up to 7 items, and then another tuple as the 8th and on and on down the line. However, there is no constraint on the 8th item at compile time. For example, this is legal code for the compiler: var tuple = new Tuple<int, int, int, int, int, int, int, double> (1, 1, 1, 1, 1, 1, 1, 1d); Even though the intellisense documentation says that TRest must be a Tuple. You do not get any error when writing or building the code, it does not manifest until runtime in the form of an ArgumentException. You can roughly implement a Tuple in a few minutes, complete with a Tuple-constrained 8th item. I just wonder why it was left off the current implementation? Is it possibly a forward-compatibility issue where they could add more elements with a hypothetical C# 5? Short version of rough implementation interface IMyTuple { } class MyTuple<T1> : IMyTuple { public T1 Item1 { get; private set; } public MyTuple(T1 item1) { Item1 = item1; } } class MyTuple<T1, T2> : MyTuple<T1> { public T2 Item2 { get; private set; } public MyTuple(T1 item1, T2 item2) : base(item1) { Item2 = item2; } } class MyTuple<T1, T2, TRest> : MyTuple<T1, T2> where TRest : IMyTuple { public TRest Rest { get; private set; } public MyTuple(T1 item1, T2 item2, TRest rest) : base(item1, item2) { Rest = rest; } } ... var mytuple = new MyTuple<int, int, MyTuple<int>>(1, 1, new MyTuple<int>(1)); // legal var mytuple2 = new MyTuple<int, int, int>(1, 2, 3); // illegal

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  • SystemStackError in Rails::ActiveSupport::Callbacks

    - by coreyward
    I'm building a Rails app that connects to Dropbox and syncs with a folder to update a personal site. I'm using Rails 3.0.3, Ruby 1.9.2, and the Dropbox gem. Right now I have a DropboxAccounts Controller, and two models: DropboxSession, which wraps calls to the gem with application-specific functionality, and DropboxAccount, which stores the session and settings in the database. After the user authorizes their account with Dropbox they're redirected back over and the DropboxAccount is saved with the authorized session. That all works just fine. My problem is that when I try to call Dropbox::API#create_folder(any path) I end up with a SystemStackError in lib/activesupport/callbacks.rb:421 which refers to the code below. If I remove the call to create the folder, it works. If I call create folder from another request, it works. I doubled the stack size to 16K to no avail. # This is called the first time a callback is called with a particular # key. It creates a new callback method for the key, calculating # which callbacks can be omitted because of per_key conditions. # def __create_keyed_callback(name, kind, object, &blk) #:nodoc: @_keyed_callbacks ||= {} @_keyed_callbacks[name] ||= begin str = send("_#{kind}_callbacks").compile(name, object) class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1 def #{name}() #{str} end # THIS IS LINE 421 protected :#{name} RUBY_EVAL true end end I'm not very familiar with Rails yet, and I'm not sure what the intention of the code above is or why it would cause a stack overflow. I'm not using any method_missing/ghost method magic in my code. I suspected it was something with a callback serialize :files but commenting it out did nothing. My DropboxAccount model contains only a call to belongs_to :user, and DropboxSession is just a handful of methods, none of which contain callbacks. Bypassing them and using the Dropbox::Session methods directly doesn't help. I hope someone on StackOverflow can help me with this stack overflow. ;)

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  • Developing Air (Flex) Applications for Android and Desktop

    - by Roaders
    I am an experienced Flex and Air Developer and love Android having owned a G1, a milestone (Droid), a Nexus One, a Galaxy S and now a Nexus S. Understandably I am interested in developing Flex applications for Android. I have just started working through the flex for android in 90 mins tutorial here: http://coenraets.org/flexandroid90/FlexAndroid90Minutes.pdf The very first step says that I have to create a Flex Mobile Project. I was under the impression that the whole point of Air is that the same application could run on many different platforms. I was intending on creating an air app with different skins that could be swapped in and out depending on the platform it was running on. This seems to imply that I will have to compile my Air app once for desktop and once for mobile. This isn't the end of the world but it's not quite how I expected it to work. I suppose that if I am creating mobile specific skins then I may as well create a mobile specific app. Is it possible to create one Air app that will run on both mobile and desktop? Is this a good idea?

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  • Project management and bundling dependencies

    - by Joshua
    I've been looking for ways to learn about the right way to manage a software project, and I've stumbled upon the following blog post. I've learned some of the things mentioned the hard way, others make sense, and yet others are still unclear to me. To sum up, the author lists a bunch of features of a project and how much those features contribute to a project's 'suckiness' for a lack of a better term. You can find the full article here: http://spot.livejournal.com/308370.html In particular, I don't understand the author's stance on bundling dependencies with your project. These are: == Bundling == Your source only comes with other code projects that it depends on [ +20 points of FAIL ] Why is this a problem, (especially given the last point)? If your source code cannot be built without first building the bundled code bits [ +10 points of FAIL ] Doesn't this necessarily have to be the case for software built against 3rd party libs? Your code needs that other code to be compiled into its library before the linker can work? If you have modified those other bundled code bits [ +40 points of FAIL ] If this is necessary for your project, then it naturally follows that you've bundled said code with yours. If you want to customize a build of some lib,say WxWidgets, you'll have to edit that projects build scripts to bulid the library that you want. Subsequently, you'll have to publish those changes to people who wish to build your code, so why not use a high level make script with the params already written in, and distribute that? Furthermore, (especially in a windows env) if your code base is dependent on a particular version of a lib (that you also need to custom compile for your project) wouldn't it be easier to give the user the code yourself (because in this case, it is unlikely that the user will already have the correct version installed)? So how would you respond to these comments, and what points may I be failing to take into consideration? Would you agree or disagree with the author's take (or mine), and why?

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  • opengl + glew in Eclipse (for windows)

    - by echo
    I'm trying to get glew to work under eclipse (mingw) in windows. Seems as if it is extremely unusual not to use Visual Studio in this context. The install instructions for glew is simply "use the project file in build/vc6/"... The glew readme also writes: "If you wish to build GLEW from scratch (update the extension data from the net or add your own extension information), you need a Unix environment (including wget, perl, and GNU make). The extension data is regenerated from the top level source directory with: make extensions" In order to get glew to work in eclipse and windows I have to compile it in a unix environment? Is there no other way? Sure, it would probably be a learning experience to pull that off (if I were to succeed) but I feel that my time is best spent actually working on my project. And even if I did manage to crosscompile everything, would it work in anything but Visual Studio? Is the whole thing unfeasible and the best solution is to install Visual Studio? Google haven't been of much help, I feel like I am the only one that has ever attempted to do this (is there a good reason this?).

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  • erlide, which eclipse/which packages?

    - by KevinDTimm
    I have downloaded eclipse 3.4 (java version) for MacOSX (carbon). I have tried to 'update' to the erlide, but see many (duplicated) options (many erlide, options that say 'only for erl SDK updates', etc.) Sometimes I get 403 errors when attempting to access http://erlide.org/update and http://erlide.sourceforge.net/update. Finally, when I get some set of options installed, I either get errors like : Loading of /Users/kevindtimm/Documents/eclipse-java-ganymede-SR2-macosx-carbon/eclipse/plugins/org.erlide.kernel.common_0.8.1.201005250801/ebin/erlide_kernel_common.beam failed: badfile (hello_world@ktmac)1> =ERROR REPORT==== 24-Nov-2010::19:17:32 === beam/beam_load.c(1768): Error loading function erlide_kernel_common:monitor/0: op put_string u u x: please re-compile this module with an R14B compiler or, when I've done different installations of erlide, I get no response in the console to : hello:hello(). Does anybody have a good reference for how to load this plug-in and which items I should install? -module(hello). -export([hello/0]). hello() -> io:write("Hello World\n"). [edit] I have installed eclipse 3.6 (c++) as requested below, and the following code still can't find hello:hello(). %%file_comment -module(hello). %% %% Include files %% %% %% Exported Functions %% -export([hello/0]). %% %% API Functions %% %% %% Local Functions %% hello() -> io:write("Hello World\n"). [/edit]

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  • How to retrieve view of MultiIndex DataFrame

    - by Henry S. Harrison
    This question was inspired by this question. I had the same problem, updating a MultiIndex DataFrame by selection. The drop_level=False solution in Pandas 0.13 will allow me to achieve the same result, but I am still wondering why I cannot get a view from the MultiIndex DataFrame. In other words, why does this not work?: >>> sat = d.xs('sat', level='day', copy=False) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\Python27\lib\site-packages\pandas\core\frame.py", line 2248, in xs raise ValueError('Cannot retrieve view (copy=False)') ValueError: Cannot retrieve view (copy=False) Of course it could be only because it is not implemented, but is there a reason? Is it somehow ambiguous or impossible to implement? Returning a view is more intuitive to me than returning a copy then later updating the original. I looked through the source and it seems this situation is checked explicitly to raise an error. Alternatively, is it possible to get the same sort of view from any of the other indexing methods? I've experimented but have not been successful. [edit] Some potential implementations are discussed here. I guess with the last question above I'm wondering what the current best solution is to index into arbitrary multiindex slices and cross-sections.

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  • gluLookAt vectors and FPS-style camera

    - by Kevin Pamplona
    I am attempting to implemented an FPS-style camera by updating three vectors: EYE, DIR, UP. These vectors are the same that are used by gluLookAt (since gluLookAt is specified by the position of the camera, the direction it is looking at, and an up vector). I have already implemented the left-right and up-down strafing movements, but I'm having a lot of trouble understanding the math behind making the camera look-around while remaining stationary. In this case, the EYE vector remains the same, while I must update DIR and UP. Below is the code I tried, but it doesn't seem to work properly. Any suggestions? Thanks. void Transform::left(float degrees, vec3& dir, vec3& up) { vec3 axis; axis = glm::normalize(up); mat3 R = rotate(-degrees, axis); dir = R*dir; dir = R*up; }; void Transform::up(float degrees, vec3& dir, vec3& up) { vec3 axis; axis=glm::normalize(glm::cross(dir,up)); mat3 R = rotate(-degrees, axis); dir = R*dir-; up = R*up; };

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  • Java Regex for matching hexadecimal numbers in a file

    - by Ranman
    So I'm reading in a file (like java program < trace.dat) which looks something like this: 58 68 58 68 40 c 40 48 FA If I'm lucky but more often it has several whitespace characters before and after each line. These are hexadecimal addresses that I'm parsing and I basically need to make sure that I can get the line using a scanner, buffered reader... whatever and make sure I can then convert the hexadecimal to an integer. This is what I have so far: Scanner scanner = new Scanner(System.in); int address; String binary; Pattern pattern = Pattern.compile("^\\s*[0-9A-Fa-f]*\\s*$", Pattern.CASE_INSENSITIVE); while(scanner.hasNextLine()) { address = Integer.parseInt(scanner.next(pattern), 16); binary = Integer.toBinaryString(address); //Do lots of other stuff here } //DO MORE STUFF HERE... So I've traced all my errors to parsing input and stuff so I guess I'm just trying to figure out what regex or approach I need to get this working the way I want.

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  • Developing ASP.Net User Control to be imported to SharePoint MOSS 2007

    - by Don Kirkham
    Apologies if this has been answered, but I could not find a similar question: I am developing a webpart for MOSS 2007. I am using WSPBuilder to built a visual webpart (ascx) and everything works fine, but the development/debug cycle is just painfully slow, so I'd like to know if it is possible (without being too painful) to develop the user control faster using an .Net Web Application project with all of the nice F5 debugging, then import the final product into my SharePoint visual webpart. The user control interacts with a LOB system (SQL) and does not reference the SharePoint API at all. (The reason I am building this as a webpart is because I don't need another web app to run this one page, so putting it into a webpart on a new webpart page on my existing site is the best solution IMO.) I would obviously need to import (reference?) my data access classes into my "temp" web app, but think that would not be too much trouble. I realize this will be extra effort to get this set up, but am thinking the payoff will be reduced development time of the actual user control using a little web application vs having to use the compile/build WSP/deploy WSP/reset ISS/test/make a change/repeat cycle that MOSS requires. (I guess SP2010/VS2010 has spoiled me with the native SharePoint tools available.)

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  • C# / IronPython Interop with shared C# Class Library

    - by Adam Haile
    I'm trying to use IronPython as an intermediary between a C# GUI and some C# libraries, so that it can be scripted post compile time. I have a Class library DLL that is used by both the GUI and the python and is something along the lines of this: namespace MyLib { public class MyClass { public string Name { get; set; } public MyClass(string name) { this.Name = name; } } } The IronPython code is as follows: import clr clr.AddReferenceToFile(r"MyLib.dll") from MyLib import MyClass ReturnObject = MyClass("Test") Then, in C# I would call it as follows: ScriptEngine engine = Python.CreateEngine(); ScriptScope scope = null; scope = engine.CreateScope(); ScriptSource source = engine.CreateScriptSourceFromFile("Script.py"); source.Execute(scope); MyClass mc = scope.GetVariable<MyClass>("ReturnObject ") When I call this last bit of code, source.Execute(scope) runs returns successfully, but when I try the GetVariable call, it throw the following exception Microsoft.Scripting.ArgumentTypeException: expected MyClass , got MyClass So, you can see that the class names are exactly the same, but for some reason it thinks they are different. The DLL is in a different directory than the .py file (I just didn't bother to write out all the path setup stuff), could it be that there is an issue with the interpreter for IronPython seeing these objects as difference because it's somehow seeing them as being in a different context or scope?

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  • Accept templated parameter of stl_container_type<string>::iterator

    - by Rodion Ingles
    I have a function where I have a container which holds strings (eg vector<string>, set<string>, list<string>) and, given a start iterator and an end iterator, go through the iterator range processing the strings. Currently the function is declared like this: template< typename ContainerIter> void ProcessStrings(ContainerIter begin, ContainerIter end); Now this will accept any type which conforms to the implicit interface of implementing operator*, prefix operator++ and whatever other calls are in the function body. What I really want to do is have a definition like the one below which explicitly restricts the amount of input (pseudocode warning): template< typename Container<string>::iterator> void ProcessStrings(Container<string>::iterator begin, Container<string>::iterator end); so that I can use it as such: vector<string> str_vec; list<string> str_list; set<SomeOtherClass> so_set; ProcessStrings(str_vec.begin(), str_vec.end()); // OK ProcessStrings(str_list.begin(), str_list.end()); //OK ProcessStrings(so_set.begin(), so_set.end()); // Error Essentially, what I am trying to do is restrict the function specification to make it obvious to a user of the function what it accepts and if the code fails to compile they get a message that they are using the wrong parameter types rather than something in the function body that XXX function could not be found for XXX class.

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  • C++ brain teaser

    - by mxp
    I recently refactored code like this (MyClass to MyClassR). class SomeMember { long m_value; public: SomeMember() : m_value(0) {} SomeMember(int a) : m_value(a) {} SomeMember(int a, int b) : m_value(a+b) {} }; class MyClass { SomeMember m_first, m_second, m_third; public: MyClass(const bool isUp, const int x, const int y) { if (isUp) { m_first = SomeMember(x); m_second = SomeMember(y); m_third = SomeMember(x, y); } else { m_first = SomeMember(y); m_second = SomeMember(x); m_third = SomeMember(y, x); } } }; class MyClassR { SomeMember m_first, m_second, m_third; public: MyClassR(const bool isUp, const int x, const int y) : m_first(isUp ? x : y) , m_second(isUp ? y : x) , m_third(isUp ? x, y : y, x) { } }; What is the error, why does it compile (at least VC6 with warning level 3 doesn't complain) and what is the right way of doing it? I (assume) I already have all these answers but I think it's and interesting problem to share.

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  • Why do I get a Illegal Access Error when running my Android tests?

    - by Janusz
    I get the following stack trace when running my Android tests on the Emulator: java.lang.NoClassDefFoundError: client.HttpHelper at client.Helper.<init>(Helper.java:14) at test.Tests.setUp(Tests.java:15) at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:164) at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:151) at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:425) at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1520) Caused by: java.lang.IllegalAccessError: cross-loader access from pre-verified class at dalvik.system.DexFile.defineClass(Native Method) at dalvik.system.DexFile.loadClass(DexFile.java:193) at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:203) at java.lang.ClassLoader.loadClass(ClassLoader.java:573) at java.lang.ClassLoader.loadClass(ClassLoader.java:532) ... 11 more I run my tests from an extra project. And it seems there are some problems with loading the classes from the other project. I have run the tests before but now they are failing. The project under tests runs without problems. Line 14 of the Helper Class is: this.httpHelper = new HttpHelper(userProfile); I start a HttpHelper class that is responsible for executing httpqueries. I think somehow this helper class is not available anymore, but I have no clue why.

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  • iPhone + Provisioning Profile + app-info.plist + entitlements.plist = iPhoneApp ? How ? What exactly

    - by sagar
    To execute my application in iPhone first of all I have to add provisioning profile in to my iPhone. Good. But I don't understand the reason behind adding a entitlements.plist in iphone application in xCode under resources. What does that entitlements.plist file do actually ? Why that .plist file have only single Boolean in it ? (get-task-allow) Can't we add that Boolean variable to application-info.plist ? I mean, I can't find the reason behind storing a single Boolean variable in separate plist file. Instead application-info.plist already contains many many application settings. Can't we just add this Boolean variable to application-info.plist. Ok, any way. I know - it won't be possible. Because we have to follow - what apple says. But, here main intention behind all these was "what is the basic need of entitlements.plist ?" or "what is the functionality of entitlements.plist ?" "How provisioning profile, entitlements.plist, application-info.plist & iPhone application compile all together & make verification on iPhone & execute it on iPhone ? "

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  • Find all CSS rules that apply to an element

    - by Carl Byström
    Many tools/APIs provide ways of selecting elements of specific classes or IDs. There's also possible to inspect the raw stylesheets loaded by the browser. However, for browsers to render an element, they'll compile all CSS rules (possibly from different stylesheet files) and apply it to the element. This is what you see with Firebug or the WebKit Inspector - the full CSS inheritance tree for an element. How can I reproduce this feature in pure JavaScript without requiring additional browser plugins? Perhaps an example can provide some clarification for what I'm looking for: <style type="text/css"> p { color :red; } #description { font-size: 20px; } </style> <p id="description">Lorem ipsum</p> Here the p#description element have two CSS rules applied: a red color and a font size of 20 px. I would like to find the source from where these computed CSS rules originate from (color comes the p rule and so on).

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  • How to use boost::transform_iterator to iterate over modifed std::map values?

    - by Frank
    I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

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  • Boost::Asio - Remove the "null"-character in the end of tcp packets.

    - by shump
    I'm trying to make a simple msn client mostly for fun but also for educational purposes. And I started to try some tcp package sending and receiving using Boost Asio as I want cross-platform support. I have managed to send a "VER"-command and receive it's response. However after I send the following "CVR"-command, Asio casts an "End of file"-error. After some further researching I found by packet sniffing that my tcp packets to the messenger server got an extra "null"-character (Ascii code: 00) at the end of the message. This means that my VER-command gets an extra character in the end which I don't think the messenger server like and therefore shuts down the connection when I try to read the CVR response. This is how my package looks when sniffing it, (it's Payload): (Hex:) 56 45 52 20 31 20 4d 53 4e 50 31 35 20 43 56 52 30 0a 0a 00 (Char:) VER 1 MSNP15 CVR 0... and this is how Adium(chat client for OS X)'s package looks: (Hex:) 56 45 52 20 31 20 4d 53 4e 50 31 35 20 43 56 52 30 0d 0a (Char:) VER 1 MSNP15 CVR 0.. So my question is if there is any way to remove the null-character in the end of each package, of if I've misunderstood something and used Asio in a wrong way. My write function (slightly edited) looks lite this: int sendVERMessage() { boost::system::error_code ignored_error; char sendBuf[] = "VER 1 MSNP15 CVR0\r\n"; boost::asio::write(socket, boost::asio::buffer(sendBuf), boost::asio::transfer_all(), ignored_error); if(ignored_error) { cout << "Failed to send to host!" << endl; return 1; } cout << "VER message sent!" << endl; return 0; } And here's the main documentation on the msn protocol I'm using. Hope I've been clear enough.

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  • How can one convince a team to use a new technology (LinQ, MVC, etc )?

    - by Atomiton
    Obviously, it's easier to do with some developers, but I'm sure many of us are on teams that prefer the status quo. You know the type. You see some benefit in a piece of new technology and they prefer the tried and true methods. Try, for example, DBA/C# programmer the advantages of using LinQ ( not necessarily LinQ to SQL, just LinQ in general ). For example, When a project requirement is to be cross-platform... instead of thinking about how one can run Windows on a Mac through a VM Machine, introducing the idea of using relatively new Silverlight or creating it in Java ( as an option to look into ). I know most people don't like to be out of their comfort level, so it takes a bit of convincing, and not ALL new technology makes business sense... but how have you convinced your team to look at a new technology? What technologies have you successfully introduced to your workplace? What technologies do you think are hardest to introduce? ( I'm thinking paradigm-shifting ones, like MVC from WebForms... or new languages ) What strategies do you employ to make these new technologies appealing?

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  • What algorithms compute directions from point A to point B on a map?

    - by A. Rex
    How do map providers (such as Google or Yahoo! Maps) suggest directions? I mean, they probably have real-world data in some form, certainly including distances but also perhaps things like driving speeds, presence of sidewalks, train schedules, etc. But suppose the data were in a simpler format, say a very large directed graph with edge weights reflecting distances. I want to be able to quickly compute directions from one arbitrary point to another. Sometimes these points will be close together (within one city) while sometimes they will be far apart (cross-country). Graph algorithms like Dijkstra's algorithm will not work because the graph is enormous. Luckily, heuristic algorithms like A* will probably work. However, our data is very structured, and perhaps some kind of tiered approach might work? (For example, store precomputed directions between certain "key" points far apart, as well as some local directions. Then directions for two far-away points will involve local directions to a key points, global directions to another key point, and then local directions again.) What algorithms are actually used in practice? PS. This question was motivated by finding quirks in online mapping directions. Contrary to the triangle inequality, sometimes Google Maps thinks that X-Z takes longer and is farther than using an intermediate point as in X-Y-Z. But maybe their walking directions optimize for another parameter, too? PPS. Here's another violation of the triangle inequality that suggests (to me) that they use some kind of tiered approach: X-Z versus X-Y-Z. The former seems to use prominent Boulevard de Sebastopol even though it's slightly out of the way. (Edit: this example doesn't work anymore, but did at the time of the original post. The one above still works as of early November 2009.)

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  • Why does GCC need extra declarations in templates when VS does not?

    - by Kyle
    template<typename T> class Base { protected: Base() {} T& get() { return t; } T t; }; template<typename T> class Derived : public Base<T> { public: Base<T>::get; // Line A Base<T>::t; // Line B void foo() { t = 4; get(); } }; int main() { return 0; } If I comment out lines A and B, this code compiles fine under Visual Studio 2008. Yet when I compile under GCC 4.1 with lines A and B commented, I get these errors: In member function ‘void TemplateDerived::foo()’: error: ‘t’ was not declared in this scope error: there are no arguments to ‘get’ that depend on a template parameter, so a declaration of ‘get’ must be available Why would one compiler require lines A and B while the other doesn't? Is there a way to simplify this? In other words, if derived classes use 20 things from the base class, I have to put 20 lines of declarations for every class deriving from Base! Is there a way around this that doesn't require so many declarations?

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  • How to do drag-n-drop and resize on an image using jQuery?

    - by Scott
    How do I resize and image using jQuery but keep its aspect ratio the same? <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title>CrossSlide - A jQuery plugin to create pan and cross-fade animations</title> <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script> </head> <body> <style type="text/css"> #resizebleImage { background: silver; } </style> <script type="text/javascript"> $(document).ready(function(){ $("#resizebleImage").resizable().parent().draggable(); }); </script> <img id="resizebleImage" src="http://images.askmen.com/galleries/singer/gloria-estefan/pictures/gloria-estefan-picture-4.jpg"> </body> </html>

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  • C++ casted realloc causing memory leak

    - by wyatt
    I'm using a function I found here to save a webpage to memory with cURL: struct WebpageData { char *pageData; size_t size; }; size_t storePage(void *input, size_t size, size_t nmemb, void *output) { size_t realsize = size * nmemb; struct WebpageData *page = (struct WebpageData *)output; page->pageData = (char *)realloc(page->pageData, page->size + realsize + 1); if(page->pageData) { memcpy(&(page->pageData[page->size]), input, realsize); page->size += realsize; page->pageData[page->size] = 0; } return realsize; } and find the line: page->pageData = (char *)realloc(page->pageData, page->size + realsize + 1); is causing a memory leak of a few hundred bytes per call. The only real change I've made from the original source is casting the line in question to a (char *), which my compiler (gcc, g++ specifically if it's a c/c++ issue, but gcc also wouldn't compile with the uncast statement) insisted upon, but I assume this is the source of the leak. Can anyone elucidate? Thanks

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  • What is the best practice for including third party jar files in a Java program?

    - by ZoFreX
    I have a program that needs several third-party libraries, and at the moment it is packaged like so: zerobot.jar (my file) libs/pircbot.jar libs/mysql-connector-java-5.1.10-bin.jar libs/c3p0-0.9.1.2.jar As far as I know the "best" way to handle third-party libs is to put them on the classpath in the manifest of my jar file, which will work cross-platform, won't slow down launch (which bundling them might) and doesn't run into legal issues (which repackaging might). The problem is for users who supply the third party libraries themselves (example use case, upgrading them to fix a bug). Two of the libraries have the version number in the file, which adds hassle. My current solution is that my program has a bootstrapping process which makes a new classloader and instantiates the program proper using it. This custom classloader adds all .jar files in lib/ to its classpath. My current way works fine, but I now have two custom classloaders in my application and a recent change to the code has caused issues that are difficult to debug, so if there is a better way I'd like to remove this complexity. It also seems like over-engineering for what I'm sure is a very common situation. So my question is, how should I be doing this?

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