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• Boost shared_ptr use_count function

  - by photo_tom

  My application problem is the following - I have a large structure foo. Because these are large and for memory management reasons, we do not wish to delete them when processing on the data is complete. We are storing them in std::vector<boost::shared_ptr<foo>>. My question is related to knowing when all processing is complete. First decision is that we do not want any of the other application code to mark a complete flag in the structure because there are multiple execution paths in the program and we cannot predict which one is the last. So in our implementation, once processing is complete, we delete all copies of boost::shared_ptr<foo>> except for the one in the vector. This will drop the reference counter in the shared_ptr to 1. Is it practical to use shared_ptr.use_count() to see if it is equal to 1 to know when all other parts of my app are done with the data. One additional reason I'm asking the question is that the boost documentation on the shared pointer shared_ptr recommends not using "use_count" for production code.

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• Stream buffering issue

  - by Kolyunya

  The mod_rewrite documentation states that it is a strict requirement to disable in(out)put buffering in a rewrite program. Keeping that in mind I've written a simple program (I do know that it lacks the EOF check but this is not an issue and it saves one condition check per loop): #include <stdio.h> #include <stdlib.h> int main ( void ) { setvbuf(stdin,NULL,_IOLBF,4200); setvbuf(stdout,NULL,_IOLBF,4200); int character; while ( 42 ) { character = getchar(); if ( character == '-' ) { character = '_'; } putchar(character); } return 42 - 42; } After making some measurements I was shocked - it was over 9,000 times slower than the demo Perl script provided by the documentation: #!/usr/bin/perl $| = 1; # Turn off I/O buffering while (<STDIN>) { s/-/_/g; # Replace dashes with underscores print $_; } Now I have two related questions: Question 1. I believe that the streams may be line buffered since Apache sends a new line after each path. Am I correct? Switching my program to setvbuf(stdin,NULL,_IOLBF,4200); setvbuf(stdout,NULL,_IOLBF,4200); makes it twice as fast as Perl one. This should not hit Apache's performance, should it? Question 2. How can one write a program in C which will use unbuffered streams (like Perl one) and will perform as fast as Perl one?

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• How to explain to client that you can't give them some of the source

  - by Bo

  We have a number of AS/Flex components that we've built over time and improved upon. They've been turned into components so they can be reused in different projects and save us time. So you can think of them as part of an in-house framework of sorts. We're now realizing that it doesn't make sense to release the source code for these components to the various clients as part of the project, because technically this code isn't really owned by the clients. So my question When a client comes to you, how do you explain to them that you can't give them the full source code for those components. The client doesn't understand the difference, he just expects you to give them all the code for the site that he paid you to do. He doesn't understand that this code has taken you a lot longer to write than what he's paying for his site. But since he doesn't understand, he would get turned off and thinks you're ripping him off or something. How do you handle this situation? What do you tell clients upfront? Do you advertise it on your site from the very beginning? How do you handle their objections so they still hire you? As a side question, how often do you give AS and Flex source code to your clients? In the case when the code doesn't have any in-house components that you reuse in several projects, and in the case when it does have in-house components.

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• C++ - Where to throw exception?

  - by HardCoder1986

  Hello! I have some kind of an ideological question, so: Suppose I have some templated function template <typename Stream> void Foo(Stream& stream, Object& object) { ... } which does something with this object and the stream (for example, serializes that object to the stream or something like that). Let's say I also add some plain wrappers like (and let's say the number of these wrappers equals 2 or 3): void FooToFile(const std::string& filename, Object& object) { std::ifstream stream(filename.c_str()); Foo(stream, object); } So, my question is: Where in this case (ideologically) should I throw the exception if my stream is bad? Should I do this in each wrapper or just move that check to my Foo, so that it's body would look like if (!foo.good()) throw (something); // Perform ordinary actions I understand that this may be not the most important part of coding and these solutions are actually equal, but I just wan't to know "the proper" way to implement this. Thank you.

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• C# properties: How are they instantiated?

  - by Pedery

  Hi! This might be a pretty straightforward question, but I'm trying to understand some of the internal workings of the compilation. Very simply put, imagine an arbitrary object being instantiated. This object is then allocated on the heap. The object has a property of type PointF (which is value type), with a get and a set method. Imagine the get and the set method containing a few calculations for doing their work. How and where (stack/heap) and when is this code instantiated? This is the background for this question: I'm writing get and set methods for an object and these methods need to be accessed very frequently. The get and set code in itself is rather massive so I feared that in a worst case scenario the methods would be instantiated as an object or a value type with all internal code for every access of the property. On the other hand the code is probably instantiated when the main object is created and the CPU is simply told to jmp to the property code start. Anyway, this is what I want to have clarified.

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• Sockets and COBOL

  - by kati

  I have received a job at a hospital which still uses COBOL for all organizational work, the whole (now 20 Terabyte) database (Which was a homebrew in, guess what, COBOL) is filled with the data of every patient since the last 45 (or so) years. So that was my story. Now to my question: Currently, all sockets were (from what I've seen) implemented by COBOL programs writing their data into files. These files then were read out by C++ programs (That was an additional module added in the late 1980s) and using C++ sockets sent to the database. Now this solution has stopped working as they are moving the database from COBOL to COBOL, yes - they didn't use MySQL or so - they implemented a new database - again in COBOL. I asked the guy that worked there before me (hes around 70 now) why the hell someone would do that and he told me that he is so good at COBOL that he doesn't want to write it in any other language. So far so good now my question: How can I implement socket connections in COBOL? I need to create an interface to the external COBOL database located at, for example, 192.168.1.23:283.

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• loop prematurely quitting

  - by Nick Gibson

  This loop works fine but prematurely quits at times. I set a piece of code in it so that I can view the random number. It only closes prematurely when the random number is equal to the highest numbered question the user inputs (Example...a user wants 10 questions, if the random number is 10 the program quits.) I have no idea why since i have it set to if(random number <= the number of questions) for ( int loop = 1; loop < loopCount; loop++ ) { aa = r.nextInt ( 10 + 1 ); abc = ( int ) aa; String[] userAnswer = new String[x]; JOptionPane.showMessageDialog ( null, abc ); if ( abc <= x ) { for ( overValue = 1; overValue < forLoop; overValue++ ); { userAnswer[j] = JOptionPane.showInputDialog ( null, "Question " + quesNum + "\n" + questions[abc] + "\n\nA: " + a[abc] + "\nB: " + b[abc] + "\nC: " + c[abc] + "\nD: " + d[abc] ); if ( userAnswer[j].equals ( answers[j] ) ) { JOptionPane.showMessageDialog ( null, "Correct. \nThe Correct Answer is " + answers[abc] ); } else { JOptionPane.showMessageDialog ( null, "Wrong. \n The Correct Answer is " + answers[abc] ); }//else }//for }//if }//for

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• Memory fragmentation @ boost::asio ?

  - by Poni

  I'm pretty much stuck with a question I never got an answer for, a question which addresses an extremely important issue; memory fragmentation at boost::asio. Found nothing at the documentation nor here at SO. The functions at boost::asio, for example async_write() & async_read_some() always allocate something. (in my case it's 144 & 96 bytes respectively, in VC9 Debug build). How do I know about it? I connect a client to the "echo server" example provided with this library. I put a breakpoint at "new.cpp" at the code of "operator new(size_t size)". Then I send "123". Breakpoint is hit! Now using the stack trace I can clearly see that the root to the "new" call is coming from the async_write() & async_read_some() calls I make in the function handlers. So memory fragmentation will come sooner or later, thus I can't use ASIO, and I wish I could! Any idea? Any helpful code example?

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• Merging Three or More Images -- PHP

  - by bballer13sn

  Before I ask my question, I'd like to thank you all in advance for helping me with this. So here's the question: So, for my website, I've been trying to make it so people's characters (which are currently composed of several pictures that are moved by CSS) are merged into one image as to make my life easier. The chunk of code that currently doesn't work is as follows: $template = $charRow['template']; $gender = $charRow['gender']; $shirt = $charRow['shirt']; $pants = $charRow['pants']; $hat = $charRow['hat']; $templatePic = imagecreatefrompng("Templates/".$template); if (!empty($shirt)) { $shirtPic = imagecreatefrompng($shirt); imagecopy($templatePic,$shirtPic,0,0,0,0,imagesx($templatePic),imagesy($templatePic)); } if (!empty($pants)) { $pantsPic = imagecreatefrompng($pants); imagecopy($templatePic,$pantsPic,0,0,0,0,imagesx($templatePic),imagesy($templatePic)); } if (!empty($hat)) { $hatPic = imagecreatefrompng($hat); imagecopy($templatePic,$hatPic,0,0,0,0,imagesx($templatePic),imagesy($templatePic)); } imagePNG($templatePic, 'Images/'); //Problem line... This is the error PHP is giving me: Warning: imagepng() [function.imagepng]: Unable to open 'Images/' for writing: Is a directory in PathToParentFolderOfFollowingFile/testFile.php on line 139 What exactly does this error mean and how can it be fixed? NOTE: $charRow is not the problem. The query to get that is just not being displayed to all of you.

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• Framework or CMS for php web development?

  - by rocknroll

  Hi all, I am a C++,Unix developer who has never dabbled in web development apart from creating simple HTML pages. I am going to change that and develop a website at a personal level soon. I am going to use php,mysql on a linux machine. In this regard I am browsing through relevant literature. The language isn't a problem but reading about CMS's and frameworks is confusing. And since I am new to web development, the number of CMS's and Frameworks are overwhelming. ? My question is do I need to have knowledge of one or more CMS' and/or Frameworks like Drupal,Joomla,Zend,Wordpress etc. If yes which is the best open source CMS' and/or Framework suggested for a newbie. ?? If the answer to the above question is yes, does the choice changes if one delves into the realms of commercial web development? Note:- I will be developing on a Linux machine, using open source tools. Thanks in advance

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• Should I be backing up a webapp's data to another host continuously ?

  - by user196289

  I have webapp in development. I need to plan for what happens if the host goes down. I will lose some very recent session status (which I can live with) and everything else should be persistently stored in the database. If I am starting up again after an outage, can I expect a good host to reconstruct the database to within minutes of where I was up to ? Or seconds ? Or should I build in a background process to continually mirror the database elsewhere ? What is normal / sensible ? Obviously a good host will have RAID and other redundancy so the likelihood of total loss should be low, and if they have periodic backups I should lose only very recent stuff but this is presumably likely to be designed with almost static web content in mind, and my site is transactional with new data being filed continuously (with a customer expectation that I don't ever lose it). Any suggestions / advice ? Are there off the shelf frameworks for doing this ? (I'm primarily working in Java) And should I just plan to save the data or should I plan to have an alternative usable host implementation ready to launch in case the host doesn't come back up in a suitable timeframe ?

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• Designing a database for a user/points system? (in Django)

  - by AP257

  First of all, sorry if this isn't an appropriate question for StackOverflow. I've tried to make it as generalisable as possible. I want to create a database (MySQL, site running Django) that has users, who can be allocated a certain number of points for various types of action - it's a collaborative game. My requirements are to obtain: the number of points a user has the user's ranking compared to all other users and the overall leaderboard (i.e. all users ranked in order of points) This is what I have so far, in my Django models.py file: class SiteUser(models.Model): name = models.CharField(max_length=250 ) email = models.EmailField(max_length=250 ) date_added = models.DateTimeField(auto_now_add=True) def points_total(self): points_added = PointsAdded.objects.filter(user=self) points_total = 0 for point in points_added: points_total += point.points return points_total class PointsAdded(models.Model): user = models.ForeignKey('SiteUser') action = models.ForeignKey('Action') date_added = models.DateTimeField(auto_now_add=True) def points(self): points = Action.objects.filter(action=self.action) return points class Action(models.Model): points = models.IntegerField() action = models.CharField(max_length=36) However it's rapidly becoming clear to me that it's actually quite complex (in Django query terms at least) to figure out the user's ranking and return the leaderboard of users. At least, I'm finding it tough. Is there a more elegant way to do something like this? This question seems to suggest that I shouldn't even have a separate points table - what do people think? It feels more robust to have separate tables, but I don't have much experience of database design.

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• Senior programming 'guru' who can't program - should I find a different career?

  - by confess

  Background: According to my resume I'm supposed to be pretty good at programming. I've worked on a ton of big projects at big companies over many years. When I go for an interview and someone looks at my resume they immediately assume I really know what I'm talking about. I generally communicate well, present myself well, know the 'jargon' and know a lot about technology at a high level, which makes matters worse because after talking to me for a while an interviewer really believes that what my resume says is probably true. The Problem: The problem arises when someone asks me to code something. I choke. As a programmer I have almost no capacity to come up with creative solutions of my own. I can't think through solutions to a programming problem the way good programmers are usually able to. I read questions on StackOverflow and the answer is obvious to me after I read other people's answers but if I am the first person to look at a question with no hints from anyone else I usually don't know where to start. At work it's the same thing. I'm fine if I'm correcting other people's code. I can identify the source of a bug quicker than anyone I work with. But if you ask me to sit down and code up a new application from scratch I will spend ten times longer than programmers who are much more junior than me. Question: Now that I am looking for work this is raising its ugly head in interview situations and making me feel desperately that I'm in the wrong career. I don't know if this problem is incompetence, laziness or some combination of these. Does anyone have any ideas about what I might be dealing with - are there books or exercises that could help me with this basic problem?

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• Best way to implement some type of ITaggable interface

  - by Jack

  I've got a program I'm creating that reports on another certain programs backup xml files. I've gotten to the point where I need to implement some type of ITaggable interface - but am unsure how to go about it code wise. My idea is that each item (BackupClient, BackupVersion, and BackupFile) should implement an ITaggable interface for highlighting old, out of date, or non-existent files in their HTML or Excel report. The user will be able to specify tags in the settings. My question is this, how can a user dynamically specify a "tag" such as File Date 3 days old? - Background Color = Red. Actually I guess my question is more, how can I, the programmer, implement this dynamically? I was thinking Expression trees, but am unsure this is the way to go as I havn't studied them much. I know my ITaggable interface would have methods such as AddTag(T tag), RemoveTag(T tag), but what exactly specifies the criteria for the tag to be added? I realize this may be subjective, and can be marked as wiki if need be, but I truly am stuck. Any input would be greatly helpful!

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• What choices do I have for a future in software development?

  - by user354892

  After graduating from college with a degree in mathematics and a minor in computer science, I took over a year to find my first programming job. I very much enjoy my work environment, but sometimes I feel like I'm not developing professionally as quickly as I am capable of. My company does mostly web programming. The project that I work on is basically a front-end for a SQL database. The entire project is (AFAIK) coded is VB.NET. I've been working on the back-end logic of the program. After some time on the job, we decided that designing web pages is not my cup of tea. It seems like the thing that I spend more time on than anything else is searching the web and SO for information about poorly documented .net and web APIs. This does not make me happy; is this normal for a programming job; I don't think it is. It really hit me the other day when i saw a question about math asked here and I didn't know the answer; I feel like my knowledge is going stale! I was previously almost hired by another company where they design graphic-intensive battle simulations for the military. I sometimes wonder what my life might be like if I had that job. I feel like my math and problem solving skills might have been a better fit at this other company. Within the wide field of software development, there are a number of directions in which to go as evidenced by the huge variety of topics discussed here on StackOverflow. I would like to feel like I'm going in the direction where I will make the most of my skills and have a satisfying career. Let me word this question as clearly as possible: given the wide breadth of the field of software development, how does it break down into sub-fields and what are the considerations for developing a software development career. I do not want to manage my career by default.

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• WPF A good way to make a view/edit control?

  - by Jefim

  Hi, this is just a question to discuss - what is the best way to make a view/edit control in WPF? E.g. we have an entity object Person, that has some props (name, surname, address, phone etc.). One presentation of the control would be a read-only view. And the other would have the edit view for this same person. Example: <UserControl x:Name="MyPersonEditor"> <Grid> <Grid x:Name="ViewGrid" Visibility="Visible"> <TextBlock Text="Name:"/> <TextBlock Text="{Binding Person.Name}"/> <Button Content="Edit" Click="ButtonEditStart_Click"/> </Grid> <Grid x:Name="EditGrid" Visibility="Collapsed"> <TextBlock Text="Name:"/> <TextBox Text="{Binding Person.Name}"/> <Button Content="Save" Click="ButtonEditEnd_Click"/> </Grid> </Grid> </UserControl> I hope that the idea is clear. The two options I see right now two grids with visibility switching and a TabControl without its header panel This is just a discussion question - not much trouble with it, yet I am just wondering if there are any other possibilities and elegant solutions to this.

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• What constitutes explicit creation of entities in LINQ to SQL? What elegant "solutions" are there to

  - by Marcelo Zabani

  Hi SO, I've been having problems with the rather famous "Explicit construction of entity type '##' in query is not allowed." error. Now, for what I understand, this exists because if explicit construction of these objects were allowed, tracking changes to the database would be very complicated. So I ask: What constitutes the explicit creation of these objects? In other terms: Why can I do this: Product foo = new Product(); foo.productName = "Something"; But can't do this: var bar = (from item in myDataContext.Products select new Product { productName = item.productName }).ToList(); I think that when running the LINQ query, some kind of association is made between the objects selected and the table rows retrieved (and this is why newing a Product in the first snippet of code is no problem at all, because no associations were made). I, however, would like to understand this a little more in depth (and this is my first question to you, that is: what is the difference from one snippet of code to another). Now, I've heard of a few ways to attack this problem: 1) The creation of a class that inherits the linq class (or one that has the same properties) 2) Selecting anonymous objects And this leads me to my second question: If you chose one of the the two approaches above, which one did you choose and why? What other problems did your approach introduce? Are there any other approaches?

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• POSIX Sockets: How to detect Ctrl-C sent over Telnet?

  - by ogott

  Short Question What's the right way to handle a Ctrl-C event sent over Telnet on the server side? Long Question After calling recv() on a socket, I'd like to handle some situations appropriately. One of them is to return a certain error code when Ctrl-C was received. What's the correct way to detect this? The following works, but it just doesn't seem right: size_t recv_count; static char ctrl_c[5] = {0xff, 0xf4, 0xff, 0xfd, 0x06}; recv_count = recv(socket, buffer, buffer_size, 0); if (recv_count == sizeof(ctrl_c) && memcmp(buffer, ctrl_c, sizeof(ctrl_c) == 0) { return CTRL_C_RECEIVED; } I found a comment on Ctrl-C in a side-note in this UNIX Socket FAQ: [...] (by the way, out-of-band is often used for that ctrl-C, too). As I understand, receiving out-of-band data is done using recv() with a certain flag as the last parameter. But when I'm waiting for data using recv() as I do in the code above, I can't read out-of-band data at the same time. Apart from that, I'm getting something using recv() without that oob-flag.

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• PHP dynamic Page-level DocBlocks

  - by Obmerk Kronen

  I was wondering if there is a way to interact with the Page-level DocBlocks. My question is more specifically about wordpress plugin development, but this question has arised also in a non-wordpress environments. The reason is mainly the possibility to easily change VERSIONS and names throughout a large project with maybe a constant definition - but that will reflect also in the docblock.. The following example Docblock is from a wordpress plugin I write - /* Plugin Name: o99 Auxilary Functions v0.4.7 Plugin URI: http://www.myurl.com Description: some simple description that nobody reads. Version: 0.4.7 Author: my cool name Author URI: http://www.ok-alsouri.com */ Is there a way to transform it into : $ver = '0.4.7'; $uri = 'http://www.myurl.com'; $desc = 'some simple description that nobody reads.'; $mcn = 'my cool name'; etc.. etc.. /* Plugin Name: o99 Auxilary Functions ($ver) Plugin URI: ($uri) Description: ($desc) Version: ($ver) Author: ($mcn) Author URI: ($$uri) */ obviously for echo to work I would need to break the docblock itself, and I can not WRITE the docblock directly into it´s own file . In shorts : can I "generate" a docblock with php itself somehow (I would think that the answer is - "no" for the page itself.. But maybe I am wrong and someone has some neat hack :-) ) Is that even possible ?

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• ( Sql Server 2005 C#.Net ) - I want just the insert query for a temp table.

  - by John Stephen

  Hi..I am using C#.Net and Sql Server ( Windows Application ). I had created a temporary table. When a button is clicked, temporary table (#tmp_emp_details) is created. I am having another button called "insert Values" and also 5 textboxes. The values that are entered in the textbox are used and whenever com.ExecuteNonQuery(); line comes, it throws an error message called "Invalid object name '#tbl_emp_answer'.". Below is the set of code..Please give me a solution. Code for insert (in insert value button): private void btninsertvalues_Click(object sender, EventArgs e) { username = txtusername.Text; examloginid = txtexamloginid.Text; question = txtquestion.Text; answer = txtanswer.Text; useranswer = txtanswer.Text; SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=tempdb;Integrated Security=True;"); SqlCommand com = new SqlCommand("Insert into #tbl_emp_answer values('"+username+"','"+examloginid+"','"+question+"','"+answer+"','"+useranswer+"')", con); con.Open(); com.ExecuteNonQuery(); con.Close(); }

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• Applying iterative algorithm to a set of rows from database

  - by Corvin

  Hello, this question may seem too basic to some, but please bear with be, it's been a while since I dealt with decent database programming. I have an algorithm that I need to program in PHP/MySQL to work on a website. It performs some computations iteratively on an array of objects (it ranks the objects based on their properties). In each iteration the algorithm runs through all collection a couple of times, accessing various data from different places of the whole collection. The algorithm needs several hundred iterations to complete. The array comes from a database. The straightforward solution that I see is to take the results of a database query and create an object for each row of the query, put the objects to an array and pass the array to my algorithm. However, I'm concerned with efficacy of such solution when I have to work with an array of several thousand of items because what I do is essentially mirror the results of a query to memory. On the other hand, making database query a couple of times on each iteration of the algorithm also seems wrong. So, my question is - what is the correct architectural solution for a problem like this? Is it OK to mirror the query results to memory? If not, which is the best way to work with query results in such an algorithm? Thanks!

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• Basic SQL Query, I am newbie

  - by user3530547

  I just started my database and query class on Monday. We met on Monday and just went over the syllabus, and on Wednesday the network at school was down so we couldn't even do the power point lecture. Right now I am working on my first homework assignment and I am almost finished but I am having trouble on one question. Here is is... Write a SELECT statement that returns one column from the Customers table named FullName that joins the LastName and FirstName columns. Format the columns with the last name, a comma, a space, and the first name like this: Doe, John Sort the result set by last name in ascending sequence. Return only the contacts whose last name begins with letters from M to Z. Here is what I have so far... USE md0577283 SELECT FirstName,LastName FROM Customers ORDER BY LastName,FirstName My question is how do I format is Lastname, FirstName like the professor wants and how do I only select names M-Z? If someone could point me in the right direction I would greatly appreciate it. Thank you. PS With all do respect, I didn't ask for the answer I asked for a nudge in the right direction so why the down vote guys?

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• two view controllers and reusability with delegate

  - by netcharmer

  Newbie question about design patterns in objC. I'm writing a functionality for my iphone app which I plan to use in other apps too. The functionality is written over two classes - Viewcontroller1 and Viewcontroller2. Viewcontroller1 is the root view of a navigation controller and it can push Viewcontroller2. Rest of the app will use only ViewController1 and will never access Viewcontroller2 directly. However, triggered by user events, Viewcontroller2 has to send a message to the rest of the app. My question is what is the best way of achieving it? Currently, I use two level of delegation to send the message out from Viewcontroller2. First send it to Viewcontroller1 and then let Viewcontroller1 send it to rest of the app or the application delegate. So my code looks like - //Viewcontroller1.h @protocol bellDelegate -(int)bellRang:(int)size; @end @interface Viewcontroller1 : UITableViewController <dummydelegate> { id <bellDelegate> delegate; @end //Viewcontroller1.m @implementation Viewcontroller1 -(void)viewDidLoad { //some stuff here Viewcontroller2 *vc2 = [[Viewcontroller2 alloc] init]; vc2.delegate = self; [self.navigationController pushViewController:vc2 animated:YES]; } -(int)dummyBell:(int)size { return([self.delegate bellRang:size]); } //Viewcontroller2.h @protocol dummyDelegate -(int)dummyBell:(int)size; @end @interface Viewcontroller2 : UITableViewController { id <dummyDelegate> delegate; @end //Viewcontroller2.m @implementation Viewcontroller2 -(int)eventFoo:(int)size { rval = [self.delegate dummyBell:size]; } @end

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• Joining tables, if percentage is above certain value

  - by CluelessGerman

  My question is similar to this one: Compare rows and get percentage However, little different. I adapted my question to the other post. I got 2 tables. First table: user_id | post_id 1 1 1 2 1 3 2 12 2 15 And second table: post_id | rating 1 1 1 2 1 3 2 1 2 5 3 null 3 1 3 4 12 4 15 1 So now I would like to count the rating for each post, in the second table. If the rating has more than, lets say, 50% positive ratings than I want to get the post_id and going it to the post_id from table one and add 1 to the user_id. At the end it would return the user_id with the number of positive posts. The result for above table would be: user_id | helpfulPosts 1 2 2 1 The post with post_id 1 and 3 have positive rating, because more than 50% have ratings of 1-3. The post with id = 2 is not positive, because the rating is exactly 50%. How would I achieve this? For clarification: It's a mysql rdbm and a positive post, is one where the number of rating_ids with 1, 2 and 3 are more than half of the overall rating. Basically the same thing, from the other thread I posted above.

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• Dependency Injection: How to pass DB around?

  - by Stephane

  Edit: This is a conceptual question first and foremost. I can make applications work without knowing this, but I'm trying to learn the concept. I've seen lots of videos with related classes and that makes sense, but when it comes to classes wrapping around other classes, I can't seem to grasp where things should be instantiated/passed around. =-=-=-=-=-=-= Question: Let's say I have a simple page that loads data from a table, manipulates the result and displays it. Simple. I'm going to use '=' for instantiating a class and '-' for passing a class in using constructor injection. It seems to me that the database has to be passed from one end of the application to the other which doesn't seem right. Here's how I would do it if I wanted to separate concerns: index =>Controller =>Model Layer =>Database =>DAO->Database I have this rule in my head that says I'm not supposed to create objects inside other objects. So what do I do with the Database? Or even the Model for that matter? I'm obviously missing something so basic about this. I would love a simplified example so that I can move forward in my code. I feel really hamstrung by this.

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