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• Simple php if query to double check

  - by skarama

  Is anything wrong with this code? <?php $variable = ; if (isset($variable)) { echo $variable ; echo "also this" ; } else echo "The variable is not set" ; ?> also, the other potential value of the variable is : $variable = <a href="http://www.mysite.com/article">This Article</a>; To clarify, I have a variable that may hold one of two possible values : an a href tag with it's url, or notihng at all. I need to have two different printouts for each of these cases, maybe I'm not doing it the right way though!

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• correct technical term for this pattern

  - by Oliver A.

  sometimes I use a pattern which is very similar to the singleton pattern: There is one default instance which and a static get method to aces it. But you may create other instances and pass it as optional parameter and if you want to and you can even replace the default instance with a instance from a child class. So it is NO SINGLETON at all but it is used like one singleton in most cases. Anyone got an idea who to call something like this ? Maybe half*** singleton? domiton?

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• What's the right way to show a non-modal child dialog in MFC (VS2005)?

  - by John

  Rather than have everything in one big dialog, I'm looking at being able to display child dialogs for separate groups of controls. The idea is these are not free-floating child dialogs like floating toolbars, but would be shown with no title-bar, their position locked to the parent dialog... so as you drag the parent dialog any open child is dragged too. NOTE: these child windows are not inside the parent dialog, they would typically be 'glued' to the edge of it. In MFC/VC++ 2005, what's the best way to do this? For testing, I currently have a standard MFC Dialog-based app setup with CMainDlg, and I've then created a 'widget dialog' CWidgetDlg. So far I've got a member variable CWidgetDlg MainDlg::m_Widget and a button on CMainDlg with a handler like CMainDlg::OnDisplayWidgetBtn() { m_Widget.ShowWindow(TRUE); } But of course m_Widget hasn't got a HWND setup, and I am trying to remember the right way to do this? For dialog controls I can use DDX but what about child dialogs? And is this a reasonable approach, or is there a nicer, more automated way?

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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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• What's the best way to return something like a collection of `std::auto_ptr`s in C++03?

  - by Billy ONeal

  std::auto_ptr is not allowed to be stored in an STL container, such as std::vector. However, occasionally there are cases where I need to return a collection of polymorphic objects, and therefore I can't return a vector of objects (due to the slicing problem). I can use std::tr1::shared_ptr and stick those in the vector, but then I have to pay a high price of maintaining separate reference counts, and object that owns the actual memory (the container) no longer logically "owns" the objects because they can be copied out of it without regard to ownership. C++0x offers a perfect solution to this problem in the form of std::vector<std::unique_ptr<t>>, but I don't have access to C++0x. Some other notes: I don't have access to C++0x, but I do have TR1 available. I would like to avoid use of Boost (though it is available if there is no other option) I am aware of boost::ptr_container containers (i.e. boost::ptr_vector), but I would like to avoid this because it breaks the debugger (innards are stored in void *s which means it's difficult to view the object actually stored inside the container in the debugger)

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• Using ANTLR with Left-Recursive Rules

  - by CNevin561

  Basically Ive written a Parse for a language with just basic arithmetic operators ( +, -, * / ) etc, but for the minus and plus cases, the Abstract Syntax Tree which is generated has parsed them as right associative when they need to be left associative. Having a googled for a solution, i found a tutorial that suggests rewriting the rule from: Expression ::= Expression <operator> Term | Term as Expression ::= Term <operator> Expression*. However in my head this seems to generate the tree the wrong way round. Any pointers on a way to resolve this issue?

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• Description format for an embedded structure

  - by praetorian20

  Hi, I have a C structure that allow users to configure options in an embedded system. Currently the GUI we use for this is custom written for every different version of this configuration structure. What I'd like for is to be able to describe the structure members in some format that can be read by the client configuration application, making it universal across all of our systems. I've experimented with describing the structure in XML and having the client read the file; this works in most cases except those where some of the fields have inter-dependencies. So the format that I use needs to have a way to specify these; for instance, member A must always be less than or equal to half of member B. Thanks in advance for your thoughts and suggestions.

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• Interpreted languages: The higher-level the faster?

  - by immersion

  I have designed around 5 experimental languages and interpreters for them so far, for education, as a hobby and for fun. One thing I noticed: The assembly-like language featuring only subroutines and conditional jumps as structures was much slower than the high-level language featuring if, while and so on. I developed them both simultaneously and both were interpreted languages. I wrote the interpreters in C++ and I tried to optimize the code-execution part to be as fast as possible. My hypothesis: In almost all cases, performance of interpreted languages rises with their level (high/low). Am I basically right with this? (If not, why?)

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• Yet another URL prefix regex question (to be used in C#).

  - by Hamish Grubijan

  Hi, I have seen many regular expressions for Url validation. In my case I want the Url to be simpler, so the regex should be tighter: Valid Url prefixes look like: http[s]://[www.]addressOrIp[.something]/PageName.aspx[?] This describe a prefix. I will be appending ?x=a&y=b&z=c later. I just want to check if the web page is live before accessing it, but even before that I want to make sure that it is properly configured. I want to treat bad url and host is down conditions differently, although when in doubt, I'd rather give a host is down message, because that is an ultimate test anyway. Hopefully that makes sense. I guess what I am trying to say - the regex does not need be too aggressive, I just want it to cover say 95% of the cases. This is C# - centric, so Perl regex extensions are not helpful to me; let's stick to the lowest common denominator. Thanks!

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• dojo dynamic right click context menu

  - by levy

  There are tons of different dojo right click context menus in a page slowing down the browser. Some divs have context menus while some others don't. So I just can't have a dynamic global context menu and still be able to fallback to the browser's built in menu in some cases, do I? The non lazy instantiation of the dojo context menus just take too much time. How can I make those context menus dynamic? Preferably being created on demand when the user actually right clicks on them.

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• Good ACL implementation in Java

  - by yonconf

  Hi All. I'm implementing a web based document management system and I'd like to implement ACLs in my system. My formal requirements are hierarchal permissions (documents inherit permissions from their folders) user groups (users can dynamically create groups and associate users with groups). Such groups can have permissions on objects in the system. My code will query permission on objects in two cases: 1. Manipulating a single document 2. Listing all documents where a manipulation is possible The latter requirement seems the achilles heel for Spring Security ACLs (their method seems likely to incur multiple DB hits for each document I manage) Anyone know of another ACL implementation? Thanks!

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• Why do we need Web-Api? [closed]

  - by user437973

  I was just wondering what the deal is with Asp.net Web-Api. Why did we need a separate type of controller in order to facilitate varying content types for action results? Why wasn't this capability just baked into the ASP.Net MVC base controller? Anyway, I was just wondering if there was a compelling reason to use both types of controllers within the same project, assuming that the project was being freshly created, or if this project structure was due to an inherent technical limitation. Would it be possible to have ApiControllers fulfill the purpose of an MVC Controller in all cases by just serving HTML when that is the specified accept type? It just seems to me like a lot of unnecessary repetition to have to re-implement the same types of actions using both types of controllers if you want those actions to be available to your web application through the API and through the web interface.

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• python-wordmatching

  - by challarao

  Write two functions, called countSubStringMatch and countSubStringMatchRecursive that take two arguments, a key string and a target string. These functions iteratively and recursively count the number of instances of the key in the target string. You should complete definitions for def countSubStringMatch(target,key): and def countSubStringMatchRecursive (target, key): For the remaining problems, we are going to explore other substring matching ideas. These problems can be solved with either an iterative function or a recursive one. You are welcome to use either approach, though you may find iterative approaches more intuitive in these cases of matching linear structures.

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• 2 IP are stored for a visitor : PROXY ?

  - by Tristan

  Hello, on my database i've decided to store IP of the visitors who answoers to polls. It's all working, but there is only 2 cases where not only 1 IP is stored, but there is 2 SAME ip for the same visitor MySQLL output (i replaced 2 numbers by XX) 10.188.XX.129, 10.188.XX.129 Here's the script to recieve the IP of the visitor : <?php function realip() { if (isset($_SERVER)) { if (isset($_SERVER["HTTP_X_FORWARDED_FOR"])) { $realip = $_SERVER["HTTP_X_FORWARDED_FOR"]; } elseif (isset($_SERVER["HTTP_CLIENT_IP"])) { $realip = $_SERVER["HTTP_CLIENT_IP"]; } else { $realip = $_SERVER["REMOTE_ADDR"]; } } else { if ( getenv( 'HTTP_X_FORWARDED_FOR' ) ) { $realip = getenv( 'HTTP_X_FORWARDED_FOR' ); } elseif ( getenv( 'HTTP_CLIENT_IP' ) ) { $realip = getenv( 'HTTP_CLIENT_IP' ); } else { $realip = getenv( 'REMOTE_ADDR' ); } } return $realip; } ? Thanks

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• In a Windows forms application, how can I use a listbox in a DataGridView coloumn instead of a combo

  - by Alex

  I'm working on a windows forms application that uses a DataGridView. Some of the cells contain a DataGridViewComboBox. In some cases, I have several values to display in the combobox. For that scenario, it would be better to use a ListBox instead of a ComboBox. Is it possible to use a multi-column listbox within a DataGridView instead of a ComboBox? If so, can you point me in the right direction? Thanks much. Al D.

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• Picture Box and Form Transparency

  - by Qu1nncunxIV

  Maybe I am missing something, but is it the case that when you set a pictureboxes background to transparent, all it really does is set it to the same color as the forms background? What I am trying to do is draw an animation for the benefit of this, a bouncing ball - which I paint on the form, then overlay that with a picture frame. End result should be a bouncing ball in a picture frame, I should mention that the picture frame does not have a straight edge, so it is not possible to arrange 4 picture boxes in a frame. The ball needs to vanish behind the frame to change color and then magically bounce back out. I have tried: 1.Setting the picture box background to pink and then key out the same pink, this basically cuts away everything, including that which is behind the picture box 2.Setting the picture box to transparent, this just displays the picture box background as the same color as the forms background. 3.I have tried painting the image in a rectangle, this had the same effect as drawing it in a picture box. I am not sure what I am doing wrong, I am wondering if there is any other ways I could try or if someone has made a custom control or library that supports transparency?

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• C++ inheritance: scoping and visibility of members

  - by Poiuyt

  Can you explain why this is not allowed, #include <stdio.h> class B { private: int a; public: int a; }; int main() { return 0; } while this is? #include <stdio.h> class A { public: int a; }; class B : public A{ private: int a; }; int main() { return 0; } In both the cases, we have one public and one private variable named a in class B. edited now!

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• In the context of an asp.net website, what's the most efficient way to check whether a User has acce

  - by scaramouch

  I have a webpage that you pass in an id parameter (via a querystring), which it then uses to fetch data from a database. Typically, a user would navigate to this page from another page that lists only those records that the user has access to. However, if they go directly to the page by typing in the URL in the Address Bar, they can effectively view any record they like. Eg. If they were to type something like http://localhost/TestSite/ClientAdmin/ManageLocation.aspx?LocationID=5 into their Address Bar, they can access the database record with the LocationID equal to five - even though they shouldn't have access to it. Now, I could solve this by doing a database check every time the page is loaded to see whether the current user has access to the record they're trying to view. However this doesn't seem very efficient given that in most cases a user won't be trying to access a record that isn't theirs. Does anyone have a better suggestion? Thanks.

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• Writing loops with i++ or ++i [duplicate]

  - by Nonesuch

  This question already has an answer here: Why use ++i instead of i++ in cases where the value is not used anywhere else in the statement? 6 answers format of for loops 31 answers I have a question about writing loops. I always begin with (int i=0; i<10; i++) But I see many experts begin with (int i=0; i<10; ++i) Is there there any real difference, or they are same? Of course, I know the difference between pre-increment and post-increment. I mean which one I should use when writing the loop? or it depends. Thanks!

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• Problems with first argument being string when overloading the + operator in C++

  - by Chris_45

  I have an selfmade Stringclass: //String.h String & operator = (const String &); String & operator = (char*); const String operator+ (String& s); const String operator+ (char* sA); . . //in main: String s1("hi"); String s2("hello"); str2 = str1 + "ok";//this is ok to do str2 = "ok" + str1;//but not this way //Shouldn't it automatically detect that one argument is a string and in both cases?

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• best method in jquery for replacing rows in a table after server side processing such as mysql sorti

  - by Kevin J

  What is the 'best practice' when returning dynamic data for a table (server side sorting, filtering etc from a db) ? Do you return just the data in json, and repeatedly clone a row element, replacing the values in each row (thus decreasing the size of the ajax call, but increasing the client side processing), or return the full html, and replace with .html or .append? Or is there another method I'm missing? This is a frequent situation in my app, and in some cases a bottleneck, and I am unsure if what I am doing is the best solution. Currently, I return the row html and use a single .append call, after emptying all the rows except the header.

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• Any way to stringify a variable id / symbol in Python?

  - by otz

  I'm wondering if it is possible at all in python to stringify variable id/symbol -- that is, a function that behaves as follows: >>> symbol = 'whatever' >>> symbol_name(symbol) 'symbol' Now, it is easy to do it on a function or a class (if it is a direct reference to the object): >>> def fn(): pass >>> fn.func_name 'fn' But I'm looking for a general method that works on all cases, even for indirect object references. I've thought of somehow using id(var), but no luck yet. Is there any way to do it?

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• How does linq decide between inner & outer joins

  - by user287795

  Hi Usually linq is using an left outer join for its queries but on some cases it decides to use inner join instead. I have a situation where that decision results in wrong results since the second table doesn't always have suitable records and that removes the records from the first table. I'm using a linqdatasource over a dbml where the relevant tables are identical but one holds historical records removed from the first. both have the same primary key. and I'm using a dataloadoption to load both tables at once with out round trips. Would you explain why linq decided to use an inner join here? Thanks

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• C++ for small, individual projects (i.e. hobby programming)

  - by Ygam

  I recently started C++. I am using PHP right now and decided to take a look at C++. Web programming had me working with a couple of languages, with a couple of people. I wanted to do programming where I only had to bother with one language and create small utility apps (mostly not web-based). I wanted a compiled, strongly-type language without memorizing a tome of classes. Basically I wanted to learn C++ for the following: mobile programming (I don't ever want to go touching Java, and I don't have a Mac for Objective C or IPhone SDK) small desktop apps like DTRs, POSs creating small desktop-based games creating small Air-like applications that can access the web for additional content I heard that C++ is not beginner-friendly and is mostly used for huge projects with lots of calculations and fine details (like 3D games). Is it practical or even possible for me to use C++ for the above cases? (Sorry, I haven't delved on C++ that much yet, so aside from "huge, monolithic project", I don't know any other uses for it)

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• Zend Framework: How to handle exceptions in Ajax requests?

  - by understack

  Normally when an exception is thrown, Error controller takes command and displays error page with regular common header and footer. This behavior is not wanted in Ajax request. Because in case of error, whole html page is sent over. And in cases where I'm directly loading the content of http response in a div, this is even more unwanted. Instead in case of Ajax request, I just want to receive 'the actual error' thrown by exception. How can I do this? I think, one dirty way could be: set a var in ajax request and process accordingly. Not a good solution.

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