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  • Create a function to a function that runs a for loop?

    - by user637364
    Hi, I have made some code that creates a red border around an image when the user click on to highlite thats the choesen one. But I want to erase previous or all border with a white border around all images before a new click is made on another image. My question is how do I activate a call to a function when a click is made and how would a function look in jQuery? I just whant to use the .css to change the border in perhaps a loop and change the id of the images? Can I mix common javascript with jQuery, or should it only be pure jQuery code in a script? This is a simplified part of the code, it contains "minibild_1" to "minibild_5" $(document).ready(function(){ $("#minibild_1").click(function(){ $("#minibild_1").css({"border":"2px solid #D00C33"}); $("#storbild").attr("src","../bilder/bilder_stora/{$row1-bild_1}.jpg"); }); $("#minibild_2").click(function(){ $("#minibild_2").css({"border":"2px solid #D00C33"}); $("#storbild").attr("src","../bilder/bilder_stora/{$row1-bild_2}.jpg"); }); });

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  • How can I prevent infinite recursion when using events to bind UI elements to fields?

    - by Billy ONeal
    The following seems to be a relatively common pattern (to me, not to the community at large) to bind a string variable to the contents of a TextBox. class MyBackEndClass { public event EventHandler DataChanged; string _Data; public string Data { get { return _Data; } set { _Data = value; //Fire the DataChanged event } } } class SomeForm : // Form stuff { MyBackEndClass mbe; TextBox someTextBox; SomeForm() { someTextBox.TextChanged += HandleTextBox(); mbe.DataChanged += HandleData(); } void HandleTextBox(Object sender, EventArgs e) { mbe.Data = ((TextBox)sender).Text; } void HandleData(Object sender, EventArgs e) { someTextBox.Text = ((MyBackEndClass) sender).Data; } } The problem is that changing the TextBox fires the changes the data value in the backend, which causes the textbox to change, etc. That runs forever. Is there a better design pattern (other than resorting to a nasty boolean flag) that handles this case correctly? EDIT: To be clear, in the real design the backend class is used to synchronize changes between multiple forms. Therefore I can't just use the SomeTextBox.Text property directly. Billy3

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  • License of popular dictionary word lists (e.g. SOWPODS, TWL)? Copyright? Trademarks?

    - by BobbyJim
    (I'm not sure if this off-topic. I found a lot of voted-up questions about software licenses and this is related. Plus, I'm sure many of us have had the situation that we need to use a dictionary in our code) I'm making a (maybe commercial) word game and need to use a good word dictionary for checking words. The most common dictionaries to use are the SOWPODS or TWL lists that are used Scrabble tournaments; see here: http://www.scrabblist.com/ (I have nothing to do with this site by the way). I've seen loads of websites offering these two dictionaries for download and loads of word games advertise that they use them. However, I cannot find any licensing terms attached to these dictionaries wherever I download them. For the players of my game, I'd want to say what dictionary I'm using (e.g. "this game uses SOWPODS"). However, I'm nervous about what I can do legally. Does anyone know about if you can copyright lists of words? Does anyone know the licenses of TWL and SOWPODS? TWL and SOWPODS don't seem to have trademarks on them but I'd like to know for sure. I cannot find any good sources for this information. EDIT: Great, now the top result for "SOWPODS license" is my stackoverflow question. :)

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  • Import data from multiple CSV files to an Excel sheet

    - by Chetan
    I need to import data from 50 similar csv files to a single excel sheet. Is there any way to get only selected columns from each file and put them together in one sheet. Structure of my csv files: A few columns exactly same in all the files. (I want them to be in excel) then one column with same column name but different data which I want to place next to each other with different names in the excel sheet. I do not not want all other remaining columns from csv files. In short, read all csv files, get all the columns which are common to all csv & put in excel sheet. Now, take one column from each file which has the same header but different data and put one after the other in excel sheet with named from the csv file name. Leave remaining rest of the columns. Write excel sheet to a excel file. Initially I thought it can be easily done, but considering my programming skill in learning stage it is way difficult for me. Please help.

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  • multi-threading in MFC

    - by kiddo
    Hello all,in my application there is a small part of function,in which it will read files to get some information,the number of filecount would be utleast 50,So I thought of implementing threading.Say if the user is giving 50 files,I wanted to separate it as 5 *10, 5 thread should be created,so that each thread can handle 10 files which can speed up the process.And also from the below code you can see that some variables are common.I read some articles about threading and I am aware that only one thread should access a variable/contorl at a me(CCriticalStiuation can be used for that).For me as a beginner,I am finding hard to imlplement what I have learned about threading.Somebody please give me some idea with code shown below..thanks in advance file read function:// void CMyClass::GetWorkFilesInfo(CStringArray& dataFilesArray,CString* dataFilesB, int* check,DWORD noOfFiles,LPWSTR path) { CString cFilePath; int cIndex =0; int exceptionInd = 0; wchar_t** filesForWork = new wchar_t*[noOfFiles]; int tempCheck; int localIndex =0; for(int index = 0;index < noOfFiles; index++) { tempCheck = *(check + index); if(tempCheck == NOCHECKBOX) { *(filesForWork+cIndex) = new TCHAR[MAX_PATH]; wcscpy(*(filesForWork+cIndex),*(dataFilesB +index)); cIndex++; } else//CHECKED or UNCHECKED { dataFilesArray.Add(*(dataFilesB+index)); *(check + localIndex) = *(check + index); localIndex++; } } WorkFiles(&cFilePath,dataFilesArray,filesForWork, path, cIndex); dataFilesArray.Add(cFilePath); *(check + localIndex) = CHECKED; }

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  • Finding patterns of failure in a Unit Test

    - by Pekka
    I'm new to Unit Testing, and I'm only getting into the routine of building test suites. I have what is going to be a rather large project that I want to build tests for from the start. I'm trying to figure out general strategies and patterns for building test suites. When you look at a class, many tests come to you obviously due to the nature of the class. Say for a "user account" class with basic CRUD operations, being related to a database table, we will want to test - well, the CRUD. creating an object and seeing whether it exists query its properties change some properties change some properties to incorrect values and delete it again. As for how to break things, there are "fail" tests common to most CRUD classes like: Invalid input data types A number as the ID key that exceeds the range of the chosen data type Input in an incorrect character encoding Input that is too long And so on and so on. For a unit test concerned with file operations, the list of "breaking things" could be Invalid characters in file name File name too long File name uses incorrect protocol or path I'm pretty sure similar patterns - applicable beyond the unit test one is currently working on - can be found for most units that are being tested. Now my question is: Am I correct in seeing such "breaking patterns"? Or am I getting something completely wrong about Unit testing, and if I did it right, this wouldn't be an issue at all? Is Unit Testing as a process of finding as many ways to break the unit as possible the right way to go? If I am correct: Are there existing definitions, lists, cheat sheets for such patterns? Are there any provisions (mainly in PHPUnit, as that's the framework I'm working in) to automate such patterns? Is there any assistance - in the form of check lists, or software - to aid in writing complete tests?

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  • Django Save Incomplete Progress on Form

    - by jimbob
    I have a django webapp with multiple users logging in and fill in a form. Some users may start filling in a form and lack some required data (e.g., a grant #) needed to validate the form (and before we can start working on it). I want them to be able to fill out the form and have an option to save the partial info (so another day they can log back in and complete it) or submit the full info undergoing validation. Currently I'm using ModelForm for all the forms I use, and the Model has constraints to ensure valid data (e.g., the grant # has to be unique). However, I want them to be able to save this intermediary data without undergoing any validation. The solution I've thought of seems rather inelegant and un-django-ey: create a "Save Partial Form" button that saves the POST dictionary converts it to a shelf file and create a "SavedPartialForm" model connecting the user to partial forms saved in the shelf. Does this seem sensible? Is there a better way to save the POST dict directly into the db? Or is an add-on module that does this partial-save of a form (which seems to be a fairly common activity with webforms)? My biggest concern with my method is I want to eventually be able to do this form-autosave automatically (say every 10 minutes) in some ajax/jquery method without actually pressing a button and sending the POST request (e.g., so the user isn't redirected off the page when autosave is triggered). I'm not that familiar with jquery and am wondering if it would be possible to do this.

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  • UpdateModelFromDatabaseException when trying to add a table to Entity Framework model

    - by Agent_9191
    I'm running into a weird issue with Entity Framework in .NET 3.5 SP1 within Visual Studio 2008. I created a database with a few tables in SQL Server and then created the associated .edmx Entity Framework model and had no issues. I then created a new table in the database that has a foreign key to an existing table and needed to be added to the .edmx. So I opened the .edmx in Visual Studio and in the models right-clicked and chose "Update Model From Database...". I saw the new table in the "add" tab, so I checked it and clicked finish. However I get an error message with the following text: --------------------------- Microsoft Visual Studio --------------------------- An exception of type 'Microsoft.Data.Entity.Design.Model.Commands.UpdateModelFromDatabaseException' occurred while attempting to update from the database. The exception message is: 'Cannot update from the database. Cannot resolve the Name Target for ScalarProperty 'ID <==> CustomerID'.'. --------------------------- OK --------------------------- For reference, here's the tables seem to be the most pertinent to the error. CustomerPreferences already exists in the .edmx. Diets is the table that was added afterwards and trying to add to the .edmx. CREATE TABLE [dbo].[CustomerPreferences]( [ID] [uniqueidentifier] NOT NULL, [LastUpdatedTime] [datetime] NOT NULL, [LastUpdatedBy] [uniqueidentifier] NOT NULL, PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] CREATE TABLE [dbo].[Diets]( [ID] [uniqueidentifier] NOT NULL, [CustomerID] [uniqueidentifier] NOT NULL, [Description] [nvarchar](50) NOT NULL, [LastUpdatedTime] [datetime] NOT NULL, [LastUpdatedBy] [uniqueidentifier] NOT NULL, PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[Diets] WITH CHECK ADD CONSTRAINT [FK_Diets_CustomerPreferences] FOREIGN KEY([CustomerID]) REFERENCES [dbo].[CustomerPreferences] ([ID]) GO ALTER TABLE [dbo].[Diets] CHECK CONSTRAINT [FK_Diets_CustomerPreferences] GO This seems like a fairly common use case, so I'm not sure where I'm going wrong.

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  • Reference remotely located assembly (web uri) from locally installed application?

    - by moonground.de
    Hi Stackoverflowers! :) We have a .NET application for Windows which is installed locally by Microsoft Installer. Now we have the need to use additional assemblies which are located online at our Web Servers. We'd like to refer to a remote uri like https://www.ourserver.com/OurProductName/ExternalLib.dll and reveal additional functionality, which is described roughly by a known common ("AddIn/Plugin") Interface. These are not 3rd Party Plugins, we just want be able to exchange parts of the application frequently, without the need to have frequent software updates. Our first idea was to add some kind of "remote refence" in Visual Studio by setting the path to the remote assembly uri. But Visual Studio downloaded the assembly immediately to a temporary directory, adding a reference to it. Our second attempt then, is simply using a WebRequest (or WebClient) to retrieve a binary stream of the Assembly, loading it "from image" by using Assembly.Load(...). This actually works, but is not very elegant and requires more additional programming for verification etc. We hoped Clickonce would provide useful techniques but apparently it's suitable for standalone applications only. (Correct me?) Is there a way (.net native or by framework/api) to reference remotely located assemblies? Thanks in advance and have a happy easter!

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  • Monads with Join() instead of Bind()

    - by MathematicalOrchid
    Monads are usually explained in turns of return and bind. However, I gather you can also implement bind in terms of join (and fmap?) In programming languages lacking first-class functions, bind is excruciatingly awkward to use. join, on the other hand, looks quite easy. I'm not completely sure I understand how join works, however. Obviously, it has the [Haskell] type join :: Monad m = m (m x) - m x For the list monad, this is trivially and obviously concat. But for a general monad, what, operationally, does this method actually do? I see what it does to the type signatures, but I'm trying to figure out how I'd write something like this in, say, Java or similar. (Actually, that's easy: I wouldn't. Because generics is broken. ;-) But in principle the question still stands...) Oops. It looks like this has been asked before: Monad join function Could somebody sketch out some implementations of common monads using return, fmap and join? (I.e., not mentioning >>= at all.) I think perhaps that might help it to sink in to my dumb brain...

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  • Checked and Unchecked operators don't seem to be working when...

    - by flockofcode
    1) Is UNCHECKED operator in effect only when expression inside UNCHECKED context uses an explicit cast ( such as byte b1=unchecked((byte)2000); ) and when conversion to particular type can happen implicitly? I’m assuming this since the following expression throws a compile time error: byte b1=unchecked(2000); //compile time error 2) a) Do CHECKED and UNCHECKED operators work only when resulting value of an expression or conversion is of an integer type? I’m assuming this since in the first example ( where double type is being converted to integer type ) CHECKED operator works as expected: double m = double.MaxValue; b=checked((byte)m); // reports an exception , while in second example ( where double type is being converted to a float type ) CHECKED operator doesn’t seem to be working. since it doesn't throw an exception: double m = double.MaxValue; float f = checked((float)m); // no exception thrown b) Why don’t the two operators also work with expressions where type of a resulting value is of floating-point type? 2) Next quote is from Microsoft’s site: The unchecked keyword is used to control the overflow-checking context for integral-type arithmetic operations and conversions I’m not sure I understand what exactly have expressions and conversions such as unchecked((byte)(100+200)); in common with integrals? Thank you

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  • How to acheieve this kind of behaviour in asp.net mvc

    - by kumar
    Hello Friends,, I have this two Action result methods. public ActionResult GetStudentInfo(StudentBE s) { return PartialView("editStudent", s); } public ActionResult GenericList() { StudentBE codes = new StudentBE(); codes.lookcodes= GetStudentCodes(new string[] { "A", "B", "C, "D", "E" }); return PartialView(codes); } // Lookcodes display dropdownlist boxes in the GeneridList view.. In genericList view I hvae beginForm.. <% using (Html.BeginForm("Updatestudent", "expense", FormMethod.Post, new { @id = "id" })) { %> <% } %> so My updatestudent method is [HttpPost] public JsonResult Updatestudent(StudentBE e) { var status = common.Update(e.student); } } return Json(status.ToString()); } Here is my problem.. the GetStudentInfo Actionresult is having each student information.. in UpdateStudent method Update Method calls the DB calls for stored procedure to update each user information now to update each user I need to call GetstudentInfo each time to get student information to update..? how to call GetStudentInfo method here to get studentinformation? student informatin may be multiple that is more than one student informaton... can anybody help me out.. thanks

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  • JavaScript for loop index strangeness

    - by pythonBOI
    I'm relatively new to JS so this may be a common problem, but I noticed something strange when dealing with for loops and the onclick function. I was able to replicate the problem with this code: <html> <head> <script type="text/javascript"> window.onload = function () { var buttons = document.getElementsByTagName('a'); for (var i=0; i<2; i++) { buttons[i].onclick = function () { alert(i); return false; } } } </script> </head> <body> <a href="">hi</a> <br /> <a href="">bye</a> </body> </html> When clicking the links I would expect to get '0' and '1', but instead I get '2' for both of them. Why is this? BTW, I managed to solve my particular problem by using the 'this' keyword, but I'm still curious as to what is behind this behavior.

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  • Risky Business with LINQ to SQL and OR Designer?

    - by Toadmyster
    I have two tables with a one to many relationship in SQL 2008. The first table (BBD) PK | BBDataID | int       | Floor_Qty | tinyint       | Construct_Year | char(4)       | etc, etc describes the data common to all buildings and the second (BBDCerts) PK | BBDCertsID | int       | BBDataID | int       | Certification_Type | varchar(20)       | etc, etc is a collection of certifications for a particular building. Thus, the primary key in BBD (BBDataID) is mapped to the corresponding field in BBDCerts via an FK relationship, but BBDCertsID is the second table's primary key and BBDataID is not because it will not be unique. My problem is that I want to be able to use the OR generated data context to get at the list of certs when I access a particular record in the BBD table. For instance: Dim vals = (From q in db.BBD Where q.BBDataID = x Select q.Floor_Qty, q.Construct_Year, q.BBDCerts).SingleOrDefault and later be able to access a particular certification like this: vals.BBDCerts.Certification_Type.First Now, the automatic associations created when the SQL tables are dropped on the design surface don't generate the EntityRef associations that are needed to access the other table using the dot notation. So, I have to use the OR designer to make the BBDCerts BBDataID a primary key (this doesn't affect the actual database), and then manually change the association properties to the appropriate OneToMany settings. There might be a better way to approach this solution but my question is, is the way I've done it safe? I've done a barrage of tests and the correct cert is referenced or updated every time. Frankly, the whole thing makes me nervous.

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  • How often should network traffic/collisions cause SNMP Sets to fail?

    - by A. Levy
    My team has a situation where an SNMP SET will fail once every two weeks or so. Since this set happens automatically, we don't necessarily notice it immediately when it fails, and this can result in an inconsistent configuration and associated wailing and gnashing of teeth. The plan is to fix this by having our software automatically retry the SET when it fails. The problem is, we aren't sure why the failure is happening. My (extremely limited) knowledge of SNMP isn't particularly helpful in diagnosing this problem, so I thought I'd ask StackOverflow for some advice. We think that every so often a spike in network traffic will cause the SET to fail. Since SNMP uses UDP for communication, I would think it would be relatively easy for a command to be drowned out if traffic was high for a short period of time. However, I have no idea how common this is. We have a small network with a single cisco router and there are less than a dozen SNMP controlled devices on that network. In addition to the SNMP traffic, there are some status web pages being loaded from the various devices. In case it makes a difference, I believe we are using the AdventNet SNMP API version 4.0.4 for Java. Does it sound reasonable that there will be some SET commands dropped occasionally, or should we be looking for other causes?

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  • How to accommodate for the next iPhones totally different screen resolution?

    - by mystify
    This is a programming question! Read on before you vote to close! According to Gizmodo, the next iPhone will have a new screen resolution: The 3.5-inch screen has a resolution of 960?×?640 pixels This little detail affects our apps in a heavy way. Most of the demo apps on the net have one thing in common: They position views in the believe that the screen has a fixed size of 320 x 480 pixels. So what most -if not all- developers do is: They designed everything in such a way, that a touchable area is -for example- 50 x 50 pixels big. Just enough to tap it. Things have been positioned relative to the upper left, to reach a specific position on screen - let's say the center, or somewhere at the bottom. So the big question is: How will the developers compensate their layout and graphics? Are there already solutions which can be used to calculate coordinates and sizes in a normalized manner, which then appear to be exactly the same when viewing them on a screen of any resolution, assuming at least that the aspect ration won't change? This is community wiki. Just add anything that you think is relevant to this huge problem (constant screen res was one of the main reasons why I didn't go for Android!!).

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  • :include and table aliasing

    - by dondo
    I'm suffering from a variant of the problem described here: ActiveRecord assigns table aliases for association joins fairly unpredictably. The first association to a given table keeps the table name. Further joins with associations to that table use aliases including the association names in the path... but it is common for app developers not to know about [other] joins at coding time. In my case I'm being bitten by a toxic mix of has_many and :include. Many tables in my schema have a state column, and the has_many wants to specify conditions on that column: has_many :foo, :conditions => {:state => 1}. However, since the state column appears in many tables, I disambiguate by explicitly specifying the table name: has_many :foo, :conditions => "this_table.state = 1". This has worked fine until now, when for efficiency I want to add an :include to preload a fairly deep tree of data. This causes the table to be aliased inconsistently in different code paths. My reading of the tickets referenced above is that this problem is not and will not be fixed in Rails 2.x. However, I don't see any way to apply the suggested workaround (to specify the aliased table name explicitly in the query). I'm happy to specify the table alias explicitly in the has_many statement, but I don't see any way to do so. As such, the workaround doesn't appear applicable to this situation (nor, I presume, in many 'named_scope' scenarios). Is there a viable workaround?

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  • Why doesn't g++ pay attention to __attribute__((pure)) for virtual functions?

    - by jchl
    According to the GCC documentation, __attribute__((pure)) tells the compiler that a function has no side-effects, and so it can be subject to common subexpression elimination. This attribute appears to work for non-virtual functions, but not for virtual functions. For example, consider the following code: extern void f( int ); class C { public: int a1(); int a2() __attribute__((pure)); virtual int b1(); virtual int b2() __attribute__((pure)); }; void test_a1( C *c ) { if( c->a1() ) { f( c->a1() ); } } void test_a2( C *c ) { if( c->a2() ) { f( c->a2() ); } } void test_b1( C *c ) { if( c->b1() ) { f( c->b1() ); } } void test_b2( C *c ) { if( c->b2() ) { f( c->b2() ); } } When compiled with optimization enabled (either -O2 or -Os), test_a2() only calls C::a2() once, but test_b2() calls b2() twice. Is there a reason for this? Is it because, even though the implementation in class C is pure, g++ can't assume that the implementation in every subclass will also be pure? If so, is there a way to tell g++ that this virtual function and every subclass's implementation will be pure?

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  • Permission Denied error in IE when closing popups

    - by Kenia
    Hi everyone! I have a simple web testing application which is supposed to open and close several popups by itself (without user interaction). For this purpose i have a javascript function to access the variable where the popup reference is stored and close it if it´s not null, fairly simple. However I get random errors in IE (in FF it works as expected, all popups are closed correctly) like Message: No such interface supported Line: 86 Char: 3 Code: 0 URI: http://10.10.0.61:10000/savmailer/adm/tests/common_tests_code.js and Message: Permission denied Line: 86 Char: 3 Code: 0 URI: http://10.10.0.61:10000/savmailer/adm/tests/common_tests_code.js The line 86 references exactly the point at which I do popup.close(); in the following function function closePopupWindow(popup){ if (popup != null) { popup.close(); popup = null; } } I have googled and it seems this permission denied error is quite common to come through among IE developers, however there´s no clear solution for it, it´s just a matter of changing the code slightly "to please" IE, so to speak. However i have no idea how to change mine since it´s just 3 lines! Tried also to change the security browser settings by adding my domain to the trusted zone, but nothing, doesn't help either. If anyone has any helpful idea or notices something i might be forgetting, please, reply to this! Thanks in advance, Kenia

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  • Tracking a fragment of a file in two places with git

    - by mabraham
    Hi, I have code such as void myfunc() { introduction(); while(condition()) { complex(); loop(); interior(); code(); } cleanup(); } which I wish to duplicate into two versions, viz: void myfuncA() { introduction(); minorchangeA(); while(condition()) { complex(); loop(); interior(); code(); } cleanup(); } void myfuncB() { introduction(); minorchangeB(); while(condition()) { complex(); modifiedB(); loop(); interior(); code(); } cleanup(); extracleanupB(); } git claims to track content rather than files, so do I need to tell it that there are chunks here that are common to both myfuncA and myfuncB so that when merging with upstream changes to myfunc that those changes should propagate to both myfuncA and myfuncB? If so, how? The code could be written so that myfuncAB did the correct thing at each point by testing for condition A or B, but that could seriously hinder readability or performance.

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  • Do double forward slashes direct IE to use specific css?

    - by kjh
    I have just found something very weird while developing a website. While trying to get a div element to display across the top of the screen, I noticed that I wasn't achieving a desired result in any browser except for old versions of IE. In order to test some different code, instead of deleting the faulty line, I used '//' to comment it out (I'm not really even sure if that works in css) but what happened was, the compatible browsers used the uncommented code, while IE used the code marked by '//'. here is the code: #ban-menu-div{ position:fixed;top:0; //position:relative; //<-- IE keeps the banner with rel pos while the other display:block; // browsers used fixed margin:auto; padding:0px; width:100%; text-align:center; background:black; } so basically, it seems as though // can be used to instruct newer browsers to ignore specific lines of code, and instruct older versions of IE to use it? If this is common practice someone please let me know. it sure makes developing for older browsers a hell of a lot easier

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  • log activity. intrusion detection. user event notification ( interraction ). messaging

    - by Julian Davchev
    Have three questions that I somehow find related so I put them in same place. Currently building relatively large LAMP system - making use of messaging(activeMQ) , memcache and other goodies. I wonder if there are best practices or nice tips and tricks on howto implement those. System is user aware - meaning all actions done can be bind to particular logged user. 1. How to log all actions/activities of users? So that stats/graphics might be extracted later for analysing. At best that will include all url calls, post data etc etc. Meaning tons of inserts. I am thinking sending messages to activeMQ and later cron dumping in DB and cron analysing might be good idea here. Since using Zend Framework I guess I may use some request plugin so I don't have to make the log() call all over the code. 2.How to log stuff so may be used for intrusion detection? I know most things might be done on http level using apache mods for example but there are also specific cases like (5 failed login attempts in a row (leads to captcha) etc etc..) This also would include tons of inserts. Here I guess direct usage of memcache might be best approach as data don't seem vital to be permanantly persisted. Not sure if cannot use data from point 1. 3.System will notify users of some events. Like need approval , something broke..whatever.Some events will need feedback(action) from user, others are just informational. Wonder if there is common solutions for needs like this. Example: Based on occuring event(s) user will be notifed (user inbox for example) what happend. There will be link or something to lead him to details of thingy that happend and take action accordingly. Those seem trivial at first look but problem I see if coding it directly is becoming really fast hard to maintain.

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  • [c++] accessing the hidden 'this' pointer

    - by Kyle
    I have a GUI architecture wherein elements fire events like so: guiManager->fireEvent(BUTTON_CLICKED, this); Every single event fired passes 'this' as the caller of the event. There is never a time I dont want to pass 'this', and further, no pointer except for 'this' should ever be passed. This brings me to a problem: How can I assert that fireEvent is never given a pointer other than 'this', and how can I simplify (and homogenize) calls to fireEvent to just: guiManager->fireEvent(BUTTON_CLICKED); At this point, I'm reminded of a fairly common compiler error when you write something like this: class A { public: void foo() {} }; class B { void oops() { const A* a = new A; a->foo(); } }; int main() { return 0; } Compiling this will give you ../src/sandbox.cpp: In member function ‘void B::oops()’: ../src/sandbox.cpp:7: error: passing ‘const A’ as ‘this’ argument of ‘void A::foo()’ discards qualifiers because member functions pass 'this' as a hidden parameter. "Aha!" I say. This (no pun intended) is exactly what I want. If I could somehow access the hidden 'this' pointer, it would solve both issues I mentioned earlier. The problem is, as far as I know you can't (can you?) and if you could, there would be outcries of "but it would break encapsulation!" Except I'm already passing 'this' every time, so what more could it break. So, is there a way to access the hidden 'this', and if not are there any idioms or alternative approaches that are more elegant than passing 'this' every time?

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  • Type-safe generic data structures in plain-old C?

    - by Bradford Larsen
    I have done far more C++ programming than "plain old C" programming. One thing I sorely miss when programming in plain C is type-safe generic data structures, which are provided in C++ via templates. For sake of concreteness, consider a generic singly linked list. In C++, it is a simple matter to define your own template class, and then instantiate it for the types you need. In C, I can think of a few ways of implementing a generic singly linked list: Write the linked list type(s) and supporting procedures once, using void pointers to go around the type system. Write preprocessor macros taking the necessary type names, etc, to generate a type-specific version of the data structure and supporting procedures. Use a more sophisticated, stand-alone tool to generate the code for the types you need. I don't like option 1, as it is subverts the type system, and would likely have worse performance than a specialized type-specific implementation. Using a uniform representation of the data structure for all types, and casting to/from void pointers, so far as I can see, necessitates an indirection that would be avoided by an implementation specialized for the element type. Option 2 doesn't require any extra tools, but it feels somewhat clunky, and could give bad compiler errors when used improperly. Option 3 could give better compiler error messages than option 2, as the specialized data structure code would reside in expanded form that could be opened in an editor and inspected by the programmer (as opposed to code generated by preprocessor macros). However, this option is the most heavyweight, a sort of "poor-man's templates". I have used this approach before, using a simple sed script to specialize a "templated" version of some C code. I would like to program my future "low-level" projects in C rather than C++, but have been frightened by the thought of rewriting common data structures for each specific type. What experience do people have with this issue? Are there good libraries of generic data structures and algorithms in C that do not go with Option 1 (i.e. casting to and from void pointers, which sacrifices type safety and adds a level of indirection)?

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  • What is better for a student programming in C++ to learn for writing GUI: C# vs QT?

    - by flashnik
    I'm a teacher(instructor) of CS in the university. The course is based on Cormen and Knuth and students program algorithms in C++. But sometimes it is good to show how an algorithm works or just a result of task through GUI. Also in my opinion it's very imporant to be able to write full programs. They will have courses concerning GUI but a three years, later, in fact, before graduatuion. I think that they should be able to write simple GUI applications earlier. So I want to teach them it. How do you think, what is more useful for them to learn: programming GUI with QT or writing GUI in C# and calling unmanaged C++ library? Update. For developing C++ applications students use MS Visual studio, so C# is already installed. But QT AFAIK also can be integrated into VS. I have following pros of C# (some were suggested there in answers): The need to make an additional layer. It's more work, but it forces you explicitly specify contract between GUI and processing data. The border between GUI and algorithms becomes very clear. It's more popular among employers. At least, in Russia where we live. It's rather common to write performance-critical algorithms in C++ and PInvoke them from well-looking C# application/ASP.Net website. Maybe it is not so widespread in the rest of the world but in Russia Windows is very popular, especially in companies and corporations due to some reasons, so most of b2b applications are Windows applications. Rapid development. It's much quicker to code in .Net then in C++ due to many reasons. And the con is that it's a new language with own specific for students. And the mess with invoking calls to library.

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