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• C++ AI Design Question

  - by disney

  Hi, I am currently writing a bot for a MMORPG. Though, currently I am stuck at trying to figure out how to nicely implement this. The design problem is related to casting the character spells in the correct order. Here is a simple example to what I need to archieve. It's not related to casting them, but doing it in the correct order. I would know how simply cast them randomly, by checking which skill has not yet been casted, but in right order as being shown in the GUI, not really. note: the skill amount may differ, it's not always 3, maximum 10 though. Charactername < foobar has 3 skills. Skill 1: Name ( random1 ) cooldown ( 1000 ms ) cast duration ( 500 ms ) Skill 2: Name ( random2 ) cooldown ( 1500 ms ) cast duration ( 700 ms ) Skill 3: Name ( random3 ) cooldown ( 2000 ms ) cast duration ( 900 ms ) I don't really know how I could implement this, if anyone has some thoughts, feel free to share. I do know that most of the people don't like the idea of cheating in games, I don't like it either, nor I am actually playing the game, but its an interesting field for me. Thank you.

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• Can knowing C actually hurt the code you write in higher level languages?

  - by Jurily

  The question seems settled, beaten to death even. Smart people have said smart things on the subject. To be a really good programmer, you need to know C. Or do you? I was enlightened twice this week. The first one made me realize that my assumptions don't go further than my knowledge behind them, and given the complexity of software running on my machine, that's almost non-existent. But what really drove it home was this Slashdot comment: The end result is that I notice the many naive ways in which traditional C "bare metal" programmers assume that higher level languages are implemented. They make bad "optimization" decisions in projects they influence, because they have no idea how a compiler works or how different a good runtime system may be from the naive macro-assembler model they understand. Then it hit me: C is just one more abstraction, like all others. Even the CPU itself is only an abstraction! I've just never seen it break, because I don't have the tools to measure it. I'm confused. Has my mind been mutilated beyond recovery, like Dijkstra said about BASIC? Am I living in a constant state of premature optimization? Is there hope for me, now that I realized I know nothing about anything? Is there anything to know, even? And why is it so fascinating, that everything I've written in the last five years might have been fundamentally wrong? To sum it up: is there any value in knowing more than the API docs tell me? EDIT: Made CW. Of course this also means now you must post examples of the interpreter/runtime optimizing better than we do :)

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• DOM manipulation

  - by bluedaniel

  Hello everyone, Im trying to use the DOM in PHP to do a pretty specific job and Ive got no luck so far, the objective is to take a string of HTML from a Wordpress blog post (from the DB, this is a wordpress plugin). And then out of that HTML replace <div id="do_not_edit">old content</div>" with <div id="do_not_edit">new content</div>" in its place. Saving anything above and below that div in its structure. Then save the HTML back into the DB, should be simple really, I have read that a regex wouldnt be the right way to go here so Ive turned to the DOM instead. The problem is I just cant get it to work, cant extract the div or anything. Help me!! UPDATE The HTML coming out of the wordpress table looks like: Congratulations on finding us here on the world wide web, we are on a mission to create a website that will show off your culinary skills better than any other website does. <div id="do_not_edit">blah blah</div> We want this website to be fun and easy to use, we strive for simple elegance and incredible functionality.We aim to provide a 'complete package'. By this we want to create a website where people can meet, share ideas and help each other out. After several different (incorrect) workings all Ive got below is: $content = ($wpdb->get_var( "SELECT `post_content` FROM $wpdb->posts WHERE ID = {$article[post_id]}" )); $doc = new DOMDocument(); $doc->validateOnParse = true; $doc->loadHTMLFile($content); $element = $doc->getElementById('do_not_edit'); echo $element;

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• What's so bad about building XML with string concatenation?

  - by wsanville

  In the thread What’s your favorite “programmer ignorance” pet peeve?, the following answer appears, with a large amount of upvotes: Programmers who build XML using string concatenation. My question is, why is building XML via string concatenation (such as a StringBuilder in C#) bad? I've done this several times in the past, as it's sometimes the quickest way for me to get from point A to point B when to comes to the data structures/objects I'm working with. So far, I have come up with a few reasons why this isn't the greatest approach, but is there something I'm overlooking? Why should this be avoided? Probably the biggest reason I can think of is you need to escape your strings manually, and most programmers will forget this. It will work great for them when they test it, but then "randomly" their apps will fail when someone throws an & symbol in their input somewhere. Ok, I'll buy this, but it's really easy to prevent the problem (SecurityElement.Escape to name one). When I do this, I usually omit the XML declaration (i.e. <?xml version="1.0"?>). Is this harmful? Performance penalties? If you stick with proper string concatenation (i.e. StringBuilder), is this anything to be concerned about? Presumably, a class like XmlWriter will also need to do a bit of string manipulation... There are more elegant ways of generating XML, such as using XmlSerializer to automatically serialize/deserialize your classes. Ok sure, I agree. C# has a ton of useful classes for this, but sometimes I don't want to make a class for something really quick, like writing out a log file or something. Is this just me being lazy? If I am doing something "real" this is my preferred approach for dealing w/ XML.

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• Move to php in windows? Concern, hints, "please don't do!"?

  - by Daniel

  I am considering to move frome Microsoft languages to PHP (just for web dev) which has quite an interesting syntax, a perlish look (but a wider programmer base) and it allows me to reuse the web without reinventing it. I have some concerns too. I would be more than happy to gather some wisdom from stackoverflow community, (challenge to my opinions warmly welcome). Here are my doubts. Efficiency. Cgi are slow, what I am supposed to use? Fastcgi? Or what else? Efficiency + stability. Is PHP on windows really stable and a good choice in terms of performances? Database. I use very often MSSQL (I regret, i like it). Could I widely and efficiently interface PHP with MSSQL (using smartly stored pro, for example). XSLT + XML performance. I work quite a lot with XML and XSLT and I really find the MS xml parser a great software component. Are parser used in PHP fast, reliable and efficient (I am interested mainly in DOM, not SAX)? Objects. Is the PHP object programming model valid end efficient? 6 Regex. How efficient is PHP processing regexp? Many thanks for your advices.

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• Do you ever make a code change and just test rather than trying to fully understand the change you'v

  - by Clay Nichols

  I'm working in a 12 year old code base which I have been the only developer on. There are times that I'll make a a very small change based on an intuition (or quantum leap in logic ;-). Usually I try to deconstruct that change and make sure I read thoroughly the code. However sometimes, (more and more these days) I just test and make sure it had the effect I wanted. (I'm a pretty thorough tester and would test even if I read the code). This works for me and we have surprisingly (compared to most software I see) few bugs escape into the wild. But what I'm wondering is whether this is just the "art" side of coding. Yes, in an ideal world you would exhaustively read every bit of code that your change modified, but I in practice, if you're confident that it only affects a small section of code, is this a common practice? I can obviously see where this would be a disastrous approach in the hands of a poor programmer. But then, I've seen programmers who ostensibly are reading the code and break stuff left and right (in their own code based which only they have been working on).

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• Python vs all the major professional languages [closed]

  - by Matt

  I've been reading up a lot lately on comparisons between Python and a bunch of the more traditional professional languages - C, C++, Java, etc, mainly trying to find out if its as good as those would be for my own purposes. I can't get this thought out of my head that it isn't good for 'real' programming tasks beyond automation and macros. Anyway, the general idea I got from about two hundred forum threads and blog posts is that for general, non-professional-level progs, scripts, and apps, and as long as it's a single programmer (you) writing it, a given program can be written quicker and more efficiently with Python than it could be with pretty much any other language. But once its big enough to require multiple programmers or more complex than a regular person (read: non-professional) would have any business making, it pretty much becomes instantly inferior to a million other languages. Is this idea more or less accurate? (I'm learning Python for my first language and want to be able to make any small app that I want, but I plan on learning C eventually too, because I want to get into driver writing eventually. So I've been trying to research each ones strengths and weaknesses as much as I can.) Anyway, thanks for any input

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• Are we in demand?

  - by dotnetdev

  I was made redundant in the end of November. This wasn't because I lacked required skills (although I'm a youngster and in career levels a junior dev - though I knew a lot more than was called for in my job). Anyway, I was laid off due to the whole recession/credit crunch thing going on. I worked for a small company and money got tight and I had to go. I haven't made a thread about this but I have seen threads about others being laid off and experiencing a similar fate. This leads me to the question: What is the job market like for developers? Are we in demand? I ask this question on a global level, but I live in London UK (in case anyone comes across this thread from the same area). I am a .NET dev but my secondary skillset is Flex (actionscript too) and Java, which my personal portfolio is made with. I hope to be strong enough in this to do this commercially, with a few more months of practise. Then I will have more jobs applicable to me. Unfortunately, I use agencies and sites like Jobserve/Monster.com but no new jobs are ever posted on there so when you apply to all the relevant jobs, then what? Whatsmore, a lot of companies are putting a freeze on recruitment. Thanks

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• Which OpenGL functions are not GPU-accelerated?

  - by Xavier Ho

  I was shocked when I read this (from the OpenGL wiki): glTranslate, glRotate, glScale Are these hardware accelerated? No, there are no known GPUs that execute this. The driver computes the matrix on the CPU and uploads it to the GPU. All the other matrix operations are done on the CPU as well : glPushMatrix, glPopMatrix, glLoadIdentity, glFrustum, glOrtho. This is the reason why these functions are considered deprecated in GL 3.0. You should have your own math library, build your own matrix, upload your matrix to the shader. For a very, very long time I thought most of the OpenGL functions use the GPU to do computation. I'm not sure if this is a common misconception, but after a while of thinking, this makes sense. Old OpenGL functions (2.x and older) are really not suitable for real-world applications, due to too many state switches. This makes me realise that, possibly, many OpenGL functions do not use the GPU at all. So, the question is: Which OpenGL function calls don't use the GPU? I believe knowing the answer to the above question would help me become a better programmer with OpenGL. Please do share some of your insights.

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• Why aren't variables declared in "try" in scope in "catch" or "finally"?

  - by Jon Schneider

  In C# and in Java (and possibly other languages as well), variables declared in a "try" block are not in scope in the corresponding "catch" or "finally" blocks. For example, the following code does not compile: try { String s = "test"; // (more code...) } catch { Console.Out.WriteLine(s); //Java fans: think "System.out.println" here instead } In this code, a compile-time error occurs on the reference to s in the catch block, because s is only in scope in the try block. (In Java, the compile error is "s cannot be resolved"; in C#, it's "The name 's' does not exist in the current context".) The general solution to this issue seems to be to instead declare variables just before the try block, instead of within the try block: String s; try { s = "test"; // (more code...) } catch { Console.Out.WriteLine(s); //Java fans: think "System.out.println" here instead } However, at least to me, (1) this feels like a clunky solution, and (2) it results in the variables having a larger scope than the programmer intended (the entire remainder of the method, instead of only in the context of the try-catch-finally). My question is, what were/are the rationale(s) behind this language design decision (in Java, in C#, and/or in any other applicable languages)?

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• Etiquette: Version bump my fork of opensource project?

  - by Ross

  This question is about etiquette and open source projects. I have forked an application from github and added two new features. The first feature has been request frequently elsewhere. I have added it. Code & implementation are clean (I think). The second feature is more of a hack. It will be of use to others, but the implementation is a little dirty in useage and more so in code. I need the feature but I don't have the skills to fully implement it properly or to a level that could be considered a worth while contrabution to the main project. How should the versioning work? Do I just bump up my version numbers care-free and push to my master branch? It is annoying to know which version is running, modifed or original, as both have the same version number. But will it be confusing when, months later, my github page has a version number the same as the original but both are actually completely different. (I have made pull requests etc. but that is not the context of my question.) The project I have forked uses ruby jeweler so has a versioning format of: Jeweler tracks the version of your project. It assumes you will be using a version in the format x.y.z. x is the 'major' version, y is the 'minor' version, and z is the patch version. Is this standard for other projects/langauges too? Are my changes patches? Thanks

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• What programming language do you wish would quietly retire? [closed]

  - by Gregory Higley

  This is the inverse of the "What programming language do you wish would catch on?" question. I was a Delphi programmer for many years, and I still appreciate its power, but I dislike verbose programming languages. So I would love to see Pascal put out to pasture. The same goes for BASIC in any form, despite the fact that it's the language I cut my teeth on. When I look at cathedrals of beauty like Haskell and REBOL, BASIC just makes me cringe. (VB.NET is tolerable, but barely. It has a few nice language features I'd like to see moved to C#.) My dislike of Pascal and VB.NET is subjective. They are powerful languages, but I dislike their syntax esthetically. Try to explain your reasoning, if you can, even if it's just "I don't like its syntax." This question is not meant to be a flame war, argumentative, or hateful. It's meant to be a straightforward, honest discussion of programmers' dislikes.

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• Using java to create a logistic model - arrays and properties

  - by Oliver Burdekin

  I'm currently trying to create a java model that will solve a problem we have. On a voluntary expedition each week we have some people leaving and some new people arriving. Accommodation is in tents. The tents sleep different numbers of people and certain rules apply. Males and females cannot be mixed and volunteers can be one of four types - school children/ research assistants/ scientific staff/ school teachers So types of volunteer and sexes cannot be mixed. Each week the manager spends hours trying to work this out so I've offered to make this model to keep my coding skills up. At present I'm working with arrays. Each tent is a 2D array [4][x] where x is the number of people it sleeps (each person sleeping there has 4 attributes). Each person is a 1D array with 4 attributes [4]. The idea is to check where people can go, cause the minimum movement for people staying on and solve this logistic problem. Does anyone have any better suggestions as to how to solve this? At present I'm finding it necessary to write a lot of code setting up and querying arrays. Any help is appreciated.

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• What are your Programming Falacies/Myths?

  - by pms1969

  I recently started a new job and as is typical of all jobs, if you've left, you get blamed for everything. Not long after I started there was a change required for an app (web based) that we maintain, and it was quickly pointed out that the actual code for this site had been lost a long time ago, and the only changes we could make to the it were ones that required changes to mark-up [it was a pre-compiled site]. Being new, I needed a little help finding my way around the code, and enlisted the services of one of my colleagues. Made my changes, and then re-enlisted his help to deploy it. While prepping for the deployment (getting the app on the QA server) we discovered that there were actually 2 different, very similarly named, folders in our source repository. It transpired that for the last year or so, mark-up changes had been made to the site directly, and these were the only differences with the code in the slightly incorrectly named folder in source control. So we did have all the code, and can now properly support the site. This put me in mind of a trick we played on a junior programmer once in a previous job, where we told him he couldn't/shouldn't do a certain thing in code as this would likely bring the server to it's knees and cost the company thousands of pounds (a gag that last months :-). And another one in the first programming job I took on - the batch commission run was just going to crash once a month and there was nothing to be done about it, causing a call out, and call out compensation for the on-call guy (a bug I fixed as soon as I became the on-call guy - 2am call outs don't work for me). So I was wondering... What other programming fallacies/myths are out there that are worth sharing?

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• trying to reenter IT field after a break of over 5 years

  - by josephj1989

  Hello I have had some misfortune in life - I was unwell and had to stay out of work for an extended period of about 5 years.Before that I used to work as an Oracle/Oracle Ebusiness suite consultant (I was charging very good contract rates). But now I am fully recovered ,feeling sharper than ever. But there arent many opportunities in my areas of expertise in a small market like New Zealand and the long absence is no help either. So for the last 5 months I have been training myself in C# ,ASP .NET,WEB technologies like HTML,JQuery,CSS and also SQL Server.I had some previous experience with JAVA and VB .NET (few months). But I am fully confident of my abilities and believe I can hit the ground running given a chance.I used to be an expert with SQL and C language and these skills are portable to SQL Server and C#. Another problem I face is my age- I am over 50. What is your opinion - Am I doing the right thing. Can I get back into an IT career-I am willing to start all over again at a junior level, I am really facing a crisis in my life.

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• Variable modification in a child process

  - by teaLeef

  I am working on Bryant and O'Hallaron's Computer Systems, A Programmer's Perspective. Exercise 8.16 asks for the output of a program like (I changed it because they use a header file you can download on their website): #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/wait.h> #include <errno.h> #include <unistd.h> #include <string.h> int counter = 1; int main() { if (fork() == 0){ counter--; exit(0); } else{ Wait(NULL); printf("counter = %d\n", ++counter); } exit(0); } I answered "counter = 1" because the parent process waits for its children to terminate and then increments counter. But the child first decrements it. However, when I tested the program, I found that the correct answer was "counter = 2". Is the variable "counter" different in the child and in the parent process? If not, then why is the answer 2?

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• C++ Constructor With Parameters Won't Initialize, Errors C2059 and C2228

  - by Some Girl

  I'm a C# programmer trying to muddle through C++ to create a Windows Forms Application. I have a Windows Form that makes use of a user-created class. Basically I'm trying to use a constructor that takes parameters, but my form won't let me initialize the object with parameter. Here's the code, hopefully somebody can explain the problem to me because I'm completely baffled... Here's my header file: BankAcct.h public ref class BankAcct { private: int money; public: BankAcct(); BankAcct(int); void Deposit(int); void GetBalance(int&); }; And my definition file: BankAcct.cpp #include "StdAfx.h" #include "BankAcct.h" BankAcct::BankAcct() { money = 0; } BankAcct::BankAcct(int startAmt) { money = startAmt; } void BankAcct::Deposit(int depAmt) { money += depAmt; } void BankAcct::GetBalance(int& balance) { balance = money; } And finally my main form. Won't copy the whole thing, of course, but I'm trying to declare the new bank account object, and start it with a balance of say $50. private: BankAcct myAccount(50); //does not work! WHY?? //private: //BankAcct myAccount; //works then in the form constructor my code is this: public: frmBank(void) { InitializeComponent(); int bal; myAccount.GetBalance(bal); lblBankBalance->Text += Convert::ToString(bal); } I've included the BankAcct.h file at the top of my frmBank.h, what else am I doing wrong here? It works great if I use the default constructor (the one that starts the bank balance at zero). I get the following error messages: error C2059: syntax error: 'constant' and error C2228: left of '.GetBalance' must have class/struct/union Thank you for any and all help on this one!!

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• Rapid Opening and Closing System.IO.StreamWriter in C#

  - by ccomet

  Suppose you have a file that you are programmatically logging information into with regards to a process. Kinda like your typical debug Console.WriteLine, but due to the nature of the code you're testing, you don't have a console to write onto so you have to write it somewhere like a file. My current program uses System.IO.StreamWriter for this task. My question is about the approach to using the StreamWriter. Is it better to open just one StreamWriter instance, do all of the writes, and close it when the entire process is done? Or is it a better idea to open a new StreamWriter instance to write a line into the file, then immediately close it, and do this for every time something needs to be written in? In the latter approach, this would probably be facilitated by a method that would do just that for a given message, rather than bloating the main process code with excessive amounts of lines. But having a method to aid in that implementation doesn't necessarily make it the better choice. Are there significant advantages to picking one approach or the other? Or are they functionally equivalent, leaving the choice on the shoulders of the programmer?

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• Sorted queue with dropping out elements

  - by ffriend

  I have a list of jobs and queue of workers waiting for these jobs. All the jobs are the same, but workers are different and sorted by their ability to perform the job. That is, first person can do this job best of all, second does it just a little bit worse and so on. Job is always assigned to the person with the highest skills from those who are free at that moment. When person is assigned a job, he drops out of the queue for some time. But when he is done, he gets back to his position. So, for example, at some moment in time worker queue looks like: [x, x, .83, x, .7, .63, .55, .54, .48, ...] where x's stand for missing workers and numbers show skill level of left workers. When there's a new job, it is assigned to 3rd worker as the one with highest skill of available workers. So next moment queue looks like: [x, x, x, x, .7, .63, .55, .54, .48, ...] Let's say, that at this moment worker #2 finishes his job and gets back to the list: [x, .91, x, x, .7, .63, .55, .54, .48, ...] I hope the process is completely clear now. My question is what algorithm and data structure to use to implement quick search and deletion of worker and insertion back to his position. For the moment the best approach I can see is to use Fibonacci heap that have amortized O(log n) for deleting minimal element (assigning job and deleting worker from queue) and O(1) for inserting him back, which is pretty good. But is there even better algorithm / data structure that possibly take into account the fact that elements are already sorted and only drop of the queue from time to time?

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• Was Visual Studio 2008 or 2010 written to use multi cores?

  - by Erx_VB.NExT.Coder

  basically i want to know if the visual studio IDE and/or compiler in 2010 was written to make use of a multi core environment (i understand we can target multi core environments in 08 and 10, but that is not my question). i am trying to decide on if i should get a higher clock dual core or a lower clock quad core, as i want to try and figure out which processor will give me the absolute best possible experience with Visual Studio 2010 (ide and background compiler). if they are running the most important section (background compiler and other ide tasks) in one core, then the core will get cut off quicker if running a quad core, esp if background compiler is the heaviest task, i would imagine this would b e difficult to seperate in more then one process, so even if it uses multi cores you might still be better off with going for a higher clock cpu if the majority of the processing is still bound to occur in one core (ie the most significant part of the VS environment). i am a vb programmer, they've made great performance improvements in beta 2, congrats, but i would love to be able to use VS seamlessly... anyone have any ideas? thanks, erx

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• How to handle 30k files in a project which requires them?

  - by Jeremiah

  Visual Studio 2010 RC - Silverlight Application We have a library of images that we need to have access to. They are given to us from a vendor (through an installer) and they are not in a database, they are files in a folder (a very large monster of a folder). We do not control when the images change, so the vendor needs to be able to override them individually. We get updates frequently enough from this vendor to state that these images change "randomly" and without our (programmer) knowledge. The problem: I don't want 30K images in SVN. Heck, I don't even want to imagine them in my Solution. However, our application requires them in order to run properly. So, our build/staging servers need access to these images (we have two build servers). The Question: How would you handle it when your application will not work as specified without access to each of 30k images and you don't control when those images change? I'm do not want to have a crazy large SVN repository. Because I don't know when any of these images change, I really don't want them in my solution (definitely do not want a large solution, either). I also don't want a bunch of manual steps to do every time these images change. Our mantra, up to this point, has always been, any developer could download from SVN, compile and run our app. These images are going to kill that mantra. I'm tempted to make a WCF service that will return images if they exist and a dummy image if they don't. This way all dev boxes will return a dummy image and our build/staging/production boxes will return real images (ones that actually have the vendor's image installer installed on). This has to be a solved problem. What have other people done to handle these types of problems? I'm open to suggestions.

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• Is there a Designer for MFC in Visual Studio like for windows forms in .NET?

  - by claws

  I'm a .NET programmer. I've never developed anything in MFC. Currently I had to write a C++ application (console) for some image processing task. I finished writing it. But the point is I need to design GUI also for this. Well, there won't be anything complex. Just a window with few Buttons, RadioButtons, Check Boxes, PicturesBox & few sliders. thats it. I'm using VS 2008 and was expecting a .NET style form designer. Just to test, I created a MFC project (with all default configuration) and these files were created by default: ChildFrm.cpp MainFrm.cpp mfc.cpp mfcDoc.cpp mfcView.cpp stdafx.cpp Now, I'm unable to find a Designer. There is no View Designer. I've opened all the above *.cpp and in the code editor right clicked to see "Designer View". ToolBox is just empty because I'm in code editor mode. When I built the project. This is the window I get. How to open a designer?

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• [PHP] Local/Dev/Live deployment - best workflow

  - by Adam Kiss

  Hello, situation We our little company with 3 people, each has a localhost webserver and most projects (previous and current) are on one PC network shared disk. We have virtual server, where some of our clients' sites and our site. Our standard workflow is: Coder PC ? Programmer localhost ? dev domain (client.company.com) ? live version (client.com) It often happens, that there are two or three guys working on same projects at the same time - one is on dev version, two are on localhost. When finished, we try to synchronize the files on dev version and ideally not to mess up any files, which *knock knock * doesn't happen often. And then one of us deploys dev version on live webserver. question we are looking for a way to simplify this workflow while updating websites - ideally some sort of diff uploader or VCS probably (Git/SVN/VCS/...), but we are not completely sure where to begin or what way would be ideal, therefore I ask you, fellow stackoverflowers for your experience with website / application deployment and recommended workflow. We probably will also need to use Mac in process, so if it won't be a problem, that would be even better. Thank you

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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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• In this example where is the C++ assignment operator used rather than the copy constructor ?

  - by Bill Forster

  As part of an ongoing process of trying to upgrade my C++ skills, I am trying to break some old habits. My old school C programmer inclination is to write this; void func( Widget &ref ) { Widget w; // default constructor int i; for( i=0; i<10; i++ ) { w = ref; // assignment operator // do stuff that modifies w } } This works well. But I think the following is closer to best practice; void func( Widget &ref ) { for( int i=0; i<10; i++ ) { Widget w = ref; // ?? // do stuff that modifies w } } With my Widget class at least, this works fine. But I don't fully understand why. I have two theories; 1) The copy constructor runs 10 times. 2) The copy constructor runs once then the assignment operator runs 9 times. Both of these trouble me a little. 2) in particular seems artificial and wrong. Is there a third possibility that I am missing ?

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