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• Simultaneous private and public inheritance in C++

  - by gspr

  Suppose a class Y publicly inherits a class X. Is it possible for a class Z to privately inherit Y while publicly inheriting X? To make this clearer, suppose X defines public methods x1 and x2. Y inherits X, overrides x1 and provides a method y. Does C++ allow for a third class Z to subclass Y in such a way that Y's implementation of x1 and y are privately available to it, while the outside world only sees it inheriting X publicly, i.e. having only a single public method x2?

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• Create JavaScript array of function pointer, without calling it

  - by sibidiba

  I have the code below. I would like to have an array (buttons) with a single element pointing to the a function (closeFlag). <script type="text/javascript"> var closeFlag = new function() { alert('Clicked'); } var buttons = { 'OK': closeFlag } </script> However, when loading the page the alert immediately pops up. When the array is constructed, instead of using it as a pointer, JavaScript calls my function. Why? What mistake, misconception do I have?

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• Need help on how to setup my packages and projects in eclipse

  - by jax

  I am new to Java and am making a license generator. This is my current setup. com.example.licensegenerator.client (used by the client application) :LicenseLoader (no Main method) :LicenseDownloader (no Main method) com.example.licensegenerator.server.keys (used by the server) :ProductKeyGenerator(Main method) com.example.licensegenerator.server.license (used on the server also) :LicenseGenerator(Main method) com.example.licensegenerator.lib (Shared classes between client and server) :Contants (no main) Now I have a few questions. Is it OK to have multiple Main() methods in a single project? Will I be able to compile them to different .jar files? (In this case I need two different jars for the server) Is there a better way to setup the packages? And a totally unrelated question, with exceptions, is it better to handle them right then and there or throw them and let the main method catch them all (the program cannot recover if an error occurs)

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• MySql returning multiple rows from stored procedure / function

  - by pistacchio

  Hi, I need to make a stored procedure or function that returns a set of rows. I've noted that in a stored procedure i can SELECT * FROM table with success. If i fetch rows in a loop and SELECT something, something_other FROM table once per loop execution, I only get one single result. What I need to do is looping, doing some calculations and returning a rowset. What's the best way to do this? A temporary table? Stored functions? Any help appreciated.

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• Which parallel sorting algorithm has the best average case performance?

  - by Craig P. Motlin

  Sorting takes O(n log n) in the serial case. If we have O(n) processors we would hope for a linear speedup. O(log n) parallel algorithms exist but they have a very high constant. They also aren't applicable on commodity hardware which doesn't have anywhere near O(n) processors. With p processors, reasonable algorithms should take O(n/p log n/p) time. In the serial case, quick sort has the best runtime complexity on average. A parallel quick sort algorithm is easy to implement (see here and here). However it doesn't perform well since the very first step is to partition the whole collection on a single core. I have found information on many parallel sort algorithms but so far I have not seen anything pointing to a clear winner. I'm looking to sort lists of 1 million to 100 million elements in a JVM language running on 8 to 32 cores.

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• Why does Java ArrayList use per-element casting instead of per-array casting?

  - by user1111929

  What happens inside Java's ArrayList<T> (and probably many other classes) is that there is an internal Object[] array = new Object[n];, to which T Objects are written. Whenever an element is read from it, a cast return (T) array[i]; is done. So, a cast on every single read. I wonder why this is done. To me, it seems like they're just doing unnecessary casts. Wouldn't it be more logical and also slightly faster to just create a T[] array = (T[]) new Object[n]; and then just return array[i]; without cast? This is only one cast per array creation, which is usually far less than the number of reads. Why is their method to be preferred? I fail to see why my idea isn't strictly better?

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• Retrieving Large Lists of Objects Using Java EE

  - by hallidave

  Is there a generally-accepted way to return a large list of objects using Java EE? For example, if you had a database ResultSet that had millions of objects how would you return those objects to a (remote) client application? Another example -- that is closer to what I'm actually doing -- would be to aggregate data from hundreds of sources, normalize it, and incrementally transfer it to a client system as a single "list". Since all the data cannot fit in memory, I was thinking that a combination of a stateful SessionBean and some sort of custom Iterator that called back to the server would do the trick. How have you successfully solved this problem in the past?

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• Breaking up large DataGridView for printing

  - by Hal

  Hey, I've got a single-row, 40 column-long DataGridView that i need to print. Since i can neither print it directly (because A4 sheets won't cut it ;)) nor adjust its width to the width of the page itself (because the headers look terrible), i wanted to break the DataGridView to 4 separate pieces and display 10 columns per row (imagine: column 1 to 10 in the first line, column 11 to 21 four or five lines below, etc...). Is there an easy way to do this? I was leaning towards a more manual approach (using fors), but i'd love to know if there's a more elegant way. Cheers

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• Which is more efficent PHP: array_intersect() OR array_intersect_key()

  - by Jordan Rutty

  Is it more efficient to use the key intersect or the value intersect if both key and value have the same contents for example: Array ( [743] => 743 [744] => 744 [745] => 745 [746] => 746 [747] => 747 [748] => 748 ) Is there any difference in performance in using one or the other with the same values. Similar to the difference of using double or single quotes?

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• How to make a change in Back End Database When my computer turn off by any fault

  - by Gulu

  i have one windows form application in v s 2010. i want to maintain a FLAG in Which there is two values of FLAG 1) yes and 2) no i want that when a form is load a Flag value is yes and The form is close the flag value is no in my back end Database It is same like sing in person on any web site..... But my Problem is that How Can i manatian it any how the my computer is turn off ....... i store a database on single computer that is server.but i also want a code for on same computer,also

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• How do I dynamically create Flex 4 AddChild actions for States?

  - by TK Kocheran

  I have an application in which I need to create mx.states.State objects on the fly, as I'm reading external data in order to create the states. Each State only has a single child, so here's my code which I was using to accomplish this: var state:State = new State(); state.name = "a"; state.overrides = [new AddChild(parent, DisplayObject(view))]; this.states.push(state); However, when I actually change a state, I get a runtime error relating to the fact that you can't call addChild on a spark.components.Group component. Is there an equivalent AddElement action for adding elements to a Group during a state change?

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• Visual Studio project build as an executable AND a DLL

  - by East of Nowhere

  In Visual Studio 2008 project properties, Application tab, I can set the Output type to Windows Application, Console Application, or Class Library. I have a project that I want to build as a stand-alone tool (console app) and be available to a couple other tools I'm working on as a class library. The VS GUI only lets me choose one or the other, and building the proj twice all the time is inconvenient. How can I set it up to build both output types in a single build job? Do I write some custom MSBuild .targets file or what?

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• Why would Django fcgi just die? How can I find out?

  - by Joe

  I'm running Django on Linux using fcgi and Lighttpd. Every now and again (about once a day) the server just dies. I'm using the latest stable release of Django, Python and Lighttpd. The only thing I can think of is that my program is opening a lot of files and executing a lot of external processes, but I'm fairly sure that side of things is watertight. Looking at the error and access logs, there's nothing exceptional happening (i.e. load isn't above normal). On those occasions where I have had exceptions from Python, these have shown up in the error.log, but when this crash happens I get nothing. Is there any way of finding out why the process died? Short of putting logging statements on every single line? Obviously I can't reproduce this so I don't know exactly where to look.

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• problem reading a csv file in python

  - by Hossein

  Hi, I am trying to read a very simple but somehow large(800Mb) csv file using the csv library in python. The delimiter is a single tab and each line consists of some numbers. Each line is a record, and I have 20681 rows in my file. I had some problems during my calculations using this file,it always stops at a certain row. I got suspicious about the number of rows in the file.I used the code below to count the number of row in this file: tfdf_Reader = csv.reader(open('v2-host_tfdf_en.txt'),delimiter=' ') c = 0 for row in tfdf_Reader: c = c + 1 print c To my surprise c is printed with the value of 61722!!! Why is this happening? What am I doing wrong?

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• conceptually different entities with a few similar properties should be stored in one table or more?

  - by Haghpanah

  Assume A and B are conceptually different entities that have a few similar properties and of course their own specific properties. In database design, should I put those two entities in one big aggregated table or two respectively designed tables. For instance, I have two types of payment; Online-payment and Manual-payment with following definition, TABLE [OnlinePayments] ( [ID] [uniqueidentifier], [UserID] [uniqueidentifier], [TrackingCode] [nvarchar](32), [ReferingCode] [nvarchar](32), [BankingAccID] [uniqueidentifier], [Status] [int], [Amount] [money], [Comments] [nvarchar](768), [CreatedAt] [datetime], [ShopingCartID] [uniqueidentifier], ) And TABLE [ManualPayments] ( [ID] [uniqueidentifier], [UserID] [uniqueidentifier], [BankingAccID] [uniqueidentifier], [BankingOrgID] [uniqueidentifier], [BranchName] [nvarchar](64), [BranchCode] [nvarchar](16), [Amount] [money], [SlipNumber] [nvarchar](64), [SlipImage] [image], [PaidAt] [datetime], [Comments] [nvarchar](768), [CreatedAt] [datetime], [IsApproved] [bit], [ApprovedByID] [uniqueidentifier], ) One of my friends told me that creating two distinct tables for such similar entities is not a well design method and they should be put in one single table for the sake of performance and ease of data manipulations. I’m now wondering what to do? What is the best practice in such a case?

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• How do I get characters common to two vectors in C++?

  - by Sam Phelps

  I am trying to compare two vector objects, and return a single vector containing all the chars which appear in both vectors. How would I go about this without writing some horribly complex manual method which compares every char in the first vector to every char in the second vector and using an if to add it to a third vector (which would be returned) if they match. Maybe my lack of real experience with vectors is making me imagine this will be harder than it really is, but I suspect there is some simplier way which I have been unable to find through searching.

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• Get text when enter is pressed in a text box in wxPython

  - by Sam

  I have a (single line) TextCtrl. The user types data into this. When they press enter, the contents of the box need to be extracted so they can be processed. I can't figure out how to catch enter being pressed. According to the docs, with the style wx.TE_PROCESS_ENTER set on my TextCtrl, it should generate a wx.EVT_COMMAND_TEXT_ENTER event when enter is pressed in the box, which I could then catch. However, wx.EVT_COMMAND_TEXT_ENTER seems not to exist (I get "module has no attribute EVT_COMMAND_TEXT_ENTER), so I'm a bit stuck. Googling just gets a couple of hits of people complaining wx.EVT_COMMAND_TEXT_ENTER doesn't work, so I guess I need another way of doing it.

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• Using Remote Web Page to Initialize iPhone App

  - by Chris_K

  My iPhone app relies on a vendor's XML feed to provide data. But that feed is not locked down. The vendor could change the format of the XML at any time, although so far they've promised not to. Since I might want to tell my app to use a different URL for its data source, I'd like to set up a single "Command Central" Web page, on my own server, to direct the app to the correct data source. In other words, each time my app starts, in the background and unseen by the user, it would visit "http://www.myserver.com/iphoneapp_data_sources.xml" to retrieve the URL for retrieving data from my vendor. That way, if my vendor suddenly changes the exact URL or the XML feed that the app needs, I can update that Web page and ensure that all installations of the app are using the correct XML feed. Does anyone have any advice or examples showing this kind of approach? It seems as if this must be a common problem, but so far I haven't found a well-established design pattern that fits it.

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• Avoiding try/catch hell in my web pages

  - by Shaun_web

  I am writing an ASP.NET website, which is a new framework for me. I find that I have a try/catch block in literally every method of my codebehind. All these try/catch blocks do is catch the exception and then pop-up an error message to the user. Isn't there some sort of global error handler in ASP.NET? It's worth noting that my error handling is within control (ASCX) pages, and I would like a way to simply get each ASCX to handle its own errors without forcing all error handling just to a single master page or a redirect...

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• Track each URL and Parameters sent from Form

  - by Arjun

  Simple question really for anyone who's been through this: I have a form that I'm placing on a site. This form submits some parameters to a site which then sends some parameters using "GET" to another site, which then opens the third site. Now the first 2 sites pass so quickly that I can not see what parameters were passed using the URL. I can do a manual check using source code but its too long and complex. I just need a simple tool or hint or firefox addon on how to track every single URL (wven if it has a META redirect) so I can read parameters being sent via the form. Thanks

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• Setting enum values to 4-byte strings - why?

  - by psychotik

  I saw code similar to this in the Mac OS SDK: enum { kAudioFileStreamProperty_ReadyToProducePackets = 'redy', kAudioFileStreamProperty_FileFormat = 'ffmt', kAudioFileStreamProperty_DataFormat = 'dfmt', kAudioFileStreamProperty_FormatList = 'flst', kAudioFileStreamProperty_MagicCookieData = 'mgic', kAudioFileStreamProperty_AudioDataByteCount = 'bcnt', kAudioFileStreamProperty_AudioDataPacketCount = 'pcnt', kAudioFileStreamProperty_MaximumPacketSize = 'psze', kAudioFileStreamProperty_DataOffset = 'doff', kAudioFileStreamProperty_ChannelLayout = 'cmap', kAudioFileStreamProperty_PacketToFrame = 'pkfr', kAudioFileStreamProperty_FrameToPacket = 'frpk', kAudioFileStreamProperty_PacketToByte = 'pkby', kAudioFileStreamProperty_ByteToPacket = 'bypk', kAudioFileStreamProperty_PacketTableInfo = 'pnfo', kAudioFileStreamProperty_PacketSizeUpperBound = 'pkub', kAudioFileStreamProperty_AverageBytesPerPacket = 'abpp', kAudioFileStreamProperty_BitRate = 'brat' }; It's the first time I've seen this - I assume the compiler assigns the 32-bit integer equivalent of the strings to the enum values. I cannot think of a single good reason why this might be preferred over using simple integers. It looks hideous in a debugger (how do you tell which of these values corresponds to 1919247481?) and makes debugging just hard in general. So, is there any reason where assigning such strings to enum values actually makes sense.

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• How to call split(token) on a string that does not contain the token without causing an error?

  - by Vorinowsky

  I have two types of strings as the IDs of elements in my HTML markup: Dates: "april-23" "march-20" and season names: "springtime" "winter" The dates have a dash separating the month and the day. The seasons are a single word with no other tokens. I want to assign the month or the season to a new variable called: time_of_year If I do this: var time_of_year = $(this).attr("id").split('-')[0]; It will work on the months but if I call it on a season name which does not contain the token, will it generate an error? What's the safe way to do this?

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• Password protected web content-- basic question

  - by nickpish

  I'm looking to create a password-protected section of my website that requires user login, and I'm wondering what approach would provide the simplest solution. For the most part, the site will be very simple and static-- i.e. no real requirement for a database/backend-- with the protected content contained in a single directory, which I've already configured on my server via htaccess. I guess I'm wondering ultimately if it's possible to use a script of some sort that will enable access to this protected directory via a form and thereby bypass the need for configuring a mySQL/PHP solution? Furthermore, this protected content is not exactly hyper-sensitive, but private nonetheless. Thanks much for any direction here.

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• Concatenating string with number in Javascript

  - by Sparky

  I'm trying to create a simple calculator in Javascript. I have an array named expression chunk[0] = 12 chunk[1] = + (the "+" sign) chunk[1] = 5 I used a for loop to loop through the chunks (chunk[]) and join then into a single expression as follows:- equation = ""; // To make var equation a string for(i = 0; i <= length; i++) { equation = equation + expression[i]; alert(expression[i]); } alert(equation); alert(expression[i]) showed values 12, + and 5. But alert(equation) showed 125 (instead of "12+5"). I need the variable equation to be "12+5" so that I can later call eval(equation) and get the value of 12+5. What am I doing wrong here?

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• How can I find out how much memory an object (rather the instance of an object) of a C++ class consu

  - by Shadow

  Hi, I am developing a Graph-class, based on boost-graph-library. A Graph-object contains a boost-graph, so to say an adjacency_list, and a map. When monitoring the total memory usage of my program, it consumes quite a lot (checked with pmap). Now, I would like to know, how much of the memory is exactly consumed by a filled object of this Graph-class? With filled I mean when the adjacency_list is full of vertices and edges. I found out, that using sizeof() doesn't bring me far. Using valgrind is also not an alternative as there is quite some memory allocation done previously and this makes the usage of valgrind impractical for this purpose. I'm also not interested in what other parts of the program cost in memory, I want to focus on one single object. Thank you.

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