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  • How can I write output to a new external file with Perl?

    - by Structure
    Maybe I am searching with the wrong keywords or this is a very basic question but I cannot find the answer to my question. I am having trouble writing the result of my whois command to a new external file. My code is below. It takes $readfilename, which is a file name which has a list of IPs, and $writefilename, which is the destination file for output. Both are user-specified. For my tests, $readfilename contains three IP addresses on three separate lines so there should be three separate whois results in the user specified output file. if ($readfilename) { open (my $inputfile, "<", $readfilename) || die "\n Cannot open the specified file. Please double check your file name and path.\n\n"; open (my $outputfile, ">", $writefilename) || die "\n Could not create write file.\n\n"; while (<$inputfile>) { my $iplookupresult = `whois $_`; print $outputfile $iplookupresult; } close $outputfile; close $inputfile; } I can execute this script and end up with a new external file, but over half of the file has binary garbage data (running on CentOS) and only one (or a portion of one) of the whois lookups is readable. I have no idea how half of my file is ending up binary... but my approach must be incorrect. Is there a better way to achieve the same result?

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  • memcached: which is faster, doing an add (and checking result), or doing a get (and set when returni

    - by Mike Sherov
    The title of this question isn't so clear, but the code and question is straightforward. Let's say I want to show my users an ad once per day. To accomplish this, every time they visit a page on my site, I check to see if a certain memcache key has any data stored on it. If so, don't show an ad. If not, store the value '1' in that key with an expiration of 86400. I can do this 2 ways: //version a $key='OPD_'.date('Ymd').'_'.$type.'_'.$user; if($memcache->get($key)===false){ $memcache->set($key,'1',false,$expire); //show ad } //version b $key='OPD_'.date('Ymd').'_'.$type.'_'.$user; if($memcache->add($key,'1',false,$expire)){ //show ad } Now, it might seem obvious that b is better, it always makes 1 memcache call. However, what is the overhead of "add" vs. "get"? These aren't the real comparisons... and I just made up these numbers, but let's say 1 add ~= 1 set ~= 5 get in terms of effort, and the average user views 5 pages a day: a: (5 get * 1 effort) + (1 set * 5 effort) = 10 units of effort b: (5 add * 5 effort) = 25 units of effort Would it make sense to always do the add call? Is this an unnecessary micro-optimization?

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  • Is there such a thing as a MemberExpression that handles a many-to-many relationship?

    - by Jaxidian
    We're trying to make it easy to write strongly-typed code in all areas of our system, so rather than setting var sortColumn = "FirstName" we'd like to say sortOption = (p => p.FirstName). This works great if the sortOption is of type Expression<Func<Person, object>> (we actually use generics in our code but that doesn't matter). However, we run into problems for many-to-many relationships because this notation breaks down. Consider this simple code: internal class Business { public IQueryable<Address> Addresses { get; set; } public string Name { get; set; } } internal class Address { public State MyState { get; set; } } internal class State { public string Abbreviation { get; set; } public int StateID { get; set; } } Is it possible to have this sort of MemberExpression to identify the StateID column off of a business? Again, the purpose of using this is not to return a StateID object, it's to just identify that property off of that entity (for sorting, filtering, and other purposes). It SEEMS to me that there should be some way to do this, even if it's not quite as pretty as foo = business.Addresses.SomeExtension(a => a.State.StateID);. Is this really possible? If more background is needed, take a look at this old question of mine. We've since updated the code significantly, but this should give you the general detailed idea of the context behind this question.

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  • scala 2.8 CanBuildFrom

    - by oxbow_lakes
    Following on from another question I asked, I wanted to understand a bit more about the Scala method TraversableLike[A].map whose signature is as follows: def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That Notice a few things about this method: it takes a function turning each A in the traversable into a B it returns That and takes an implicit argument of type CanBuildFrom[Repr, B, That] I can call this as follows: > val s: Set[Int] = List("Paris", "London").map(_.length) s: Set[Int] Set(5,6) What I cannot quite grasp is how the fact that That is bound to B (i.e. it is some collection of B's) is being enforced by the compiler. The type parameters look to be independent in both the signature above and in the signature of the trait CanBuildFrom itself: trait CanBuildFrom[-From, -Elem, +To] How is the scala compiler ensuring that That cannot be forced into something which does not make sense? > val s: Set[String] = List("Paris", "London").map(_.length) //will not compile EDIT - this question of course boils down to: How does the compiler decide what implicit CanBuildFrom objects are in scope for the call?

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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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  • EF Query with conditional include that uses Joins

    - by makerofthings7
    This is a follow up to another user's question. I have 5 tables CompanyDetail CompanyContacts FK to CompanyDetail CompanyContactsSecurity FK to CompanyContact UserDetail UserGroupMembership FK to UserDetail How do I return all companies and include the contacts in the same query? I would like to include companies that contain zero contacts. Companies have a 1 to many association to Contacts, however not every user is permitted to see every Contact. My goal is to get a list of every Company regardless of the count of Contacts, but include contact data. Right now I have this working query: var userGroupsQueryable = _entities.UserGroupMembership .Where(ug => ug.UserID == UserID) .Select(a => a.GroupMembership); var contactsGroupsQueryable = _entities.CompanyContactsSecurity;//.Where(c => c.CompanyID == companyID); /// OLD Query that shows permitted contacts /// ... I want to "use this query inside "listOfCompany" /// //var permittedContacts= from c in userGroupsQueryable //join p in contactsGroupsQueryable on c equals p.GroupID //select p; However this is inefficient when I need to get all contacts for all companies, since I use a For..Each loop and query each company individually and update my viewmodel. Question: How do I shoehorn the permittedContacts variable above and insert that into this query: var listOfCompany = from company in _entities.CompanyDetail.Include("CompanyContacts").Include("CompanyContactsSecurity") where company.CompanyContacts.Any( // Insert Query here.... // b => b.CompanyContactsSecurity.Join(/*inner*/,/*OuterKey*/,/*innerKey*/,/*ResultSelector*/) ) select company; My attempt at doing this resulted in: var listOfCompany = from company in _entities.CompanyDetail.Include("CompanyContacts").Include("CompanyContactsSecurity") where company.CompanyContacts.Any( // This is concept only... doesn't work... from grps in userGroupsQueryable join p in company.CompanyContactsSecurity on grps equals p.GroupID select p ) select company;

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  • How is machine code understood by the machine

    - by Kraken
    I have a very naive question here, and I would like you to correct me on whatever wrong concepts I put out here. The question is as follows: I have ubuntu installed on my machine, now I write a helloWorld.c program in C language. Now, on the operating system I have a compiler installed, when I execute my helloWorld.c program, the OS schedules the compiler and that basically compiles my code into machine code, which eventually, I execute. Now my kernel code is written in C, then how does my machine interprets that code? Say my kernel code is helloWorld.c, now would not I require any compiler, to compile this code. Also, if I hardcode a compiler in maybe ROM or something, then what language is it written in? Assembly language? Let me know if I have made myself clear with the problem. Thanks. EDIT: By kernel code I mean, the code for operating system. Operating System code. I guess it is written in C right?

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  • Why should I install Python packages into `~/.local`?

    - by Matthew Rankin
    Background I don't develop using OS X's system provided Python versions (on OS X 10.6 that's Python 2.5.4 and 2.6.1). I don't install anything in the site-packages directory for the OS provided versions of Python. (The only exception is Mercurial installed from a binary package, which installs two packages in the Python 2.6.1 site-packages directory.) I installed three versions of Python, all using the Mac OS X installer disk image: Python 2.6.6 Python 2.7 Python 3.1.2 I don't like polluting the site-packages directory for my Python installations. So I only install the following five base packages in the site-packages directory. For the actual method/commands used to install these, see SO Question 4324558. setuptools/ez_setup distribute pip virtualenv virtualenvwrapper All other packages are installed in virtualenvs. I am the only user of this MacBook. Questions Given the above background, why should I install the five base packages in ~/.local? Since I'm installing these base packages into the site-packages directories of Python distributions that I've installed, I'm isolated from the OS X's Python distributions. Using this method, should I be concerned about Glyph's comment that other things could potentially break (see his comment below)? Again, I'm only interested in where to install those five base packages. Related Questions/Info I'm asking because of Glyph's comment to my answer to SO question 4314376, which stated: NO. NEVER EVER do sudo python setup.py install whatever. Write a ~/.pydistutils.cfg that puts your pip installation into ~/.local or something. Especially files named ez_setup.py tend to suck down newer versions of things like setuptools and easy_install, which can potentially break other things on your operating system. Previously, I asked What's the proper way to install pip, virtualenv, and distribute for Python?. However, no one answered the "why" of using ~/.local.

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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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  • 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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  • 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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  • Travelling software. Is that a concept?

    - by Bubba88
    Hi! This is barely a sensible question. I would like to ask if there existed a program, which were intended to travel (for example following some physical forces) across the planet, possibly occupying and freeing computational resources/nodes. Literally that means that some agent-based system is just regularly changing it's location and (inevitably to some extent) configuration. An example would be: suppose you have external sensors, and free computers - nodes - across the space; would it make sense to self-replicate agents to follow the initializers from sensors, but in such restrictive manner that the computation is only localized at where the physical business is going on. I want to stress that this question is just for 'theoretical' fun, cause I cannot see any practical benefits of the restrictions mentioned, apart from the optimization of 'outdated' (outplaced?) agent disposal. But maybe it could be of some interest. Thank you! EDIT: It's obvious that a virus is fitting example, although the deletion of such agents is rarely of concern of the developers. More precisely, I'm interested in 'travelling' software - that is, when the count (or at least order) of the agents is kind of constant, and it's just the whole system who travels.

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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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  • 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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  • Objective C : UIButton image with NSArray in a random order

    - by Sarah
    Brief Idea about the flow : I have say minimum 1 and maximum 18 records in my database with a text and an image from which I have to fetch images and place any 3 of the same randomly to 3 UIButtons among which one image should match with my question. i.e. 1 is the answer and other 2 are the distractors. For Example : Question is : where is Apple? Now among the bunch of images, I want to place any 3 images on the 3 UIButtons(1 answer i.e. An Apple and 2 distractors) in a random order and on selecting the UIButton it should prompt me if it's a right answer or not. I am implementing below code for placing the UIImages in a random order : -(void) placeImages { NSMutableArray *images = [NSMutableArray arrayWithArray:arrImg]; NSArray *buttons = [NSArray arrayWithObjects:btn1,btn2,btn3, nil]; for (UIButton *btn in buttons) { int randomIndex= random() % images.count; UIImage *img = [images objectAtIndex:randomIndex]; [btn setImage:img forState:UIControlStateNormal]; [images removeObjectAtIndex:randomIndex]; } } But I am stuck at a point that how should I get 1 UIButton image with an answer and other as distractors also that how should i maintain the index of the image from the NSArray? Kindly guide me. Thank you.

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  • One Common View In Every ViewController

    - by l3v
    I am having a hard time wording this when searching the internet so I am just going to ask the question. I have an options view in my app that slides into view when the user clicks a button. This options view will display app information like settings. I want this options view to be displayed on every view controller in my app. I do not want to copy and paste the code for the options view into every viewcontroller file. The options view has quite a few outlets and actions and also calls many delegates. How can I reuse this options view in all my view controllers without adding all the outlets, actions, and delegate methods each time? I was going to make a new file with public methods, but I would still have to copy the outlets. Would this public methods file have to include delegate methods as well then? Let me know if my question does not make sense. I am hoping there is a standard way of implementing something like this.

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  • I can't find the homepage for my ASP.NET MVC site :(

    - by Pure.Krome
    Hi folks, really simple question here. when I remove the default route, I returns an empty page to the browser :- routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); Now before everyone starts shouting "that's because that's the default route to access all action methods, etc.." .. i know that. My question is - what code / routes does the default framework try and call .. which makes that Default Route get used/kick in? Why? I don't wish to make that my default route regex (don't ask why - this is some R&D) but I still need the main home page .. ie. Home/Index . If i try and just add that route, it doesn't get called and an empty page is returned. So -- what does the framework try and call when a user doesn't provide any urls? It's like there's some secret default document stuff set up? Cheers :)

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  • How to make smooth movements in OpenGL?

    - by thyrgle
    So this kind of on topic to my other OpenGL question (not my OpenGL ES question but OpenGL the desktop version). If you have someone press a key to move a square how do you make the square movement naturally and less jumpy but also at the same speed I have it now? This is my code for the glutKeyboardFunc() function: void handleKeypress(unsigned char key, int x, int y) { if (key == 'w') { for (int i = 0; i < 12; i++) { if (i == 1 || i == 7 || i == 10 || i == 4) { square[i] = square[i] + 1; } } glutPostRedisplay(); } if (key == 'd') { for (int i = 0; i < 12; i++) { if (i == 0 || i % 3 == 0) { square[i] = square[i] + 1; } } glutPostRedisplay(); } if (key == 's') { for (int i = 0; i < 12; i++) { if (i == 1 || i == 7 || i == 10 || i == 4) { square[i] = square[i] - 1; } } glutPostRedisplay(); } if (key == 'a') { for (int i = 0; i < 12; i++) { if (i == 0 || i % 3 == 0) { square[i] = square[i] - 1; } } glutPostRedisplay(); } } I'm sorry if this doesn't quite make sense I'll try to rephrase it in a better way if it doesn't make sense.

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  • Managing modes in Windows application working directly with SQL Server 2008

    - by hgulyan
    Hi, I have a MS Access 97 application (but the question is general) working directly with SQL Server 2008 (without application server or anything). Numbers of users can be up to 1000. Windows Authentication is used. The question is: How to handle modes, so some users will be allowed to work in read-only mode some users won't have access to db for some time My versions: Using a table with a mode id for every group of users, that will work the same way. On Form Load application will query that table for mode id. Using trigger on the tables, that must work according to that mode. The trigger will query mode value and doesn't work if access is closed or it's in read-only mode I know it's not these are not the best solutions, that's why I'm asking for your advice. There's one more point. If the mode is changed to "access-is-closed" for a group of users, that group must not be able to query to DB starting that moment. With first solution I wrote it won't work, because user can be in application at that moment and no form load event will work. How can I do this? Is there any optimal solution? Thank you. Any help would be appreciated.

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  • How to make cakePHP retreive the data represented by a foreign key?

    - by XL
    Greetings cake experts, I have a question that I think would really help a lot of people getting started with cakePHP. I have a feeling it will be easy for some of you, but it is quite challenging to me. I have a simple database with multiple tables. I can't figure out how to make cakePHP display the values associated with a foreign key in an index view. Or create a view where the fields of my choice (the ones that make sense to users like location name - not location_id can be updated or viewed on a single page). I have created an example at http://lovecats.cakeapp.com that illustrate the question. If you look at the page and click the "list cats", you will notice that it shows the location_id field from the locations table. You will also notice that when you click "add cats", you must choose a location_id from the locations table. This is the automagic way that cakePHP builds the app. I want this to be the field location_name. The database is setup so that the table cats has a foreign key called location_id that has a relationship to a table called locations. This is my problem: I want these pages to display the location_name instead of the location_id. If you want to login to the application, you can go to http://cakeapp.com/sqldesigners/sql/lovecats and the password 'password' to look at the db relationships, etc. How do I have a page that shows the fields that I want? And is it possible to create a page that updates fields from all of the tables at once? This is the slice of cake that I have been trying to figure out and this would REALLY get me over a hump. You can download the app and sql from the above url.

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  • How can pointers to functions point to something that doesn't exist in memory yet? Why do prototypes have different addresses?

    - by Kacy Raye
    To my knowledge, functions do not get added to the stack until run-time after they are called in the main function. So how can a pointer to a function have a function's memory address if it doesn't exist in memory? For example: using namespace std; #include <iostream> void func() { } int main() { void (*ptr)() = func; cout << reinterpret_cast<void*>(ptr) << endl; //prints 0x8048644 even though func never gets added to the stack } Also, this next question is a little less important to me, so if you only know the answer to my first question, then that is fine. But anyway, why does the value of the pointer ( the memory address of the function ) differ when I declare a function prototype and implement the function after main? In the first example, it printed out 0x8048644 no matter how many times I ran the program. In the next example, it printed out 0x8048680 no matter how many times I ran the program. For example: using namespace std; #include <iostream> void func(); int main() { void ( *ptr )() = func; cout << reinterpret_cast<void*>(ptr) << endl; } void func(){ }

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  • Keeping a web app project organized?

    - by user246114
    Hi, I'm writing a web app, using jsp to create the page content. I need a pretty good amount of javascript to make the app work. Does anyone have any recommendations on how to structure my project, such that it doesn't become a mess? This is a broad question, but the basic problem is that I'm insert javascript code directly into my jsp content. Then I might have some external js files. Ids and such are strewn between multiple files. I'm not really sure what a best practice is for keeping this type of project organized. Do you always keep your javascript in separate files? There has to be a few hooks in the jsp pages though for them, right? I tried using GWT because I'm really a c/java developer, and I was hoping it would help keep my project more organized (definitely helps) - but GWT is a pain to use with jsp, it really wants you to do all UI generation client side after the page is done loading, doesn't work for what I need to do. Again, broad question, any tips would be great, Thanks

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  • Template Syntax in C++

    - by Crystal
    I don't understand templates really and was trying to run a simple find the minimum for ints, doubles, chars. First question, why is template<typename T> sometimes used, and other times template<>? Second question, I do not know what I am doing wrong with the following code below: #include <iostream> template <typename T> T minimum(T arg1, T arg2) { return arg1 < arg2 ? arg1 : arg2; } template <typename T> // first I tried template <> instd of above, but wasn't sure the difference T minimum<const char *>(const char *arg1, const char *arg2) { return strcmp(arg1, arg2) ? arg2 : arg1; } int main() { std::cout << minimum<int>(4, 2) << '\n'; std::cout << minimum<double>(2.2, -56.7) << '\n'; std::cout << minimum(2.2, 2) << '\n'; } Compile Errors: error C2768: 'minimum' : illegal use of explicit template arguments error C2783: 'T minimum(const char *,const char *)' : could not deduce template argument for 'T' : see declaration of 'minimum' : error C2782: 'T minimum(T,T)' : template parameter 'T' is ambiguous : see declaration of 'minimum' Third, in getting familiar with separating .h and .cpp files, if I wanted this minimum() function to be a static function of my class, but it was the only function in that class, would I have to have a template class as well? I originally tried doing it that way instead of having it all in one file and I got some compile errors as well that I can't remember right now and was unsure how I would do that. Thanks!

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  • ArrayIndexOutOfBoundsException double array size

    - by Andy
    I'm going to preface this question with this statement: I know that I can easily handle this problem by reading the amount of lines in a file and making an array that size. I am not allowed to do this. Anyway, here is my question. I need to double my array's size whenever my program encounters an ArrayIndexOutOfBoundsException and then copy all the previous read in information into the larger array. Here is my code public static void main(String[] args) throws IOException { Scanner inScan, fScan = null; int [] A = new int[5]; inScan = new Scanner(System.in); System.out.print("Please enter the file to read from: "); while(true) { try{ String fName = inScan.nextLine(); fScan = new Scanner(new File(fName)); break; } catch (FileNotFoundException ex) { System.out.println("Your file is invalid -- please re-enter"); } } String nextItem; int nextInt = 0; int i = 0; while (fScan.hasNextLine()) { try { nextItem = fScan.nextLine(); nextInt = Integer.parseInt(nextItem); A[i] = nextInt; i++; } catch (NumberFormatException e) { System.out.println("Found an invalid int -- ignored"); } catch (ArrayIndexOutOfBoundsException e) { //double the size of array A until //copy all previous read in information to the larger array } } System.out.println("Here are your " + i + " items:"); for (int j = 0; j < i; j++) { System.out.println(A[j] + " "); } } }

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  • Learning Java Swing (GUI builder or not?)

    - by Paul
    Well I know basic Java and wanted to learn Swing so of course looked at the Sun website first, where this tutorial is. I was going to start it but realised it relied heavily on NetBeans, which I'm not sure about. I'm not sure because it's learning that I want to acheive, not a nice looking program. So I thought using NetBeans like this would be great once I know it, but I don't want to be building things without a clue what's going on underneath, and of course this could also cause problems later. My first question is is this the right way to do it, should I try not to rely on an IDE heavily? Looking through questions on the site most people recommend using the Sun tutorial, and I've only seen one answer that agrees with what I'm thinking, and they linked to this resource which looks promising. Or perhaps I'm getting the wrong idea of the Sun tutorial, perhaps it doesn't rely on the IDE, it just seemed like that. My second question is, if you agree with me, what resources (apart from the one above) would you recommend? Thanks for your answers.

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