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• GoTo statements and alternatives in VB.NET

  - by qais

  I've posted a code snippet on another forum asking for help and people pointed out to me that using GoTo statements is very bad programming practice. I'm wondering: why is it bad? What alternatives to GoTo are there to use in VB.NET that would be considered generally more of a better practice? Consider this snippet below where the user has to input their date of birth. If the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if there's a better way to do this, I'd appreciate if you could tell me that also :D) How would I be able to loop back to ask the user again? retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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• How to create an iPad directory view like animation?

  - by mahes25

  In the recent iOS 4.2 update, Apple introduced a nice animation for creating one level directories. I am trying to figure out how to implement a similar animation in my project. I would deeply appreciate it if anyone could give me any pointers to do this efficiently. From my investigation, I believe this animation or effect could be done very efficiently using Core Image which would allow me to write a custom filter. Unfortunately, Core Image is not available in iPhone. So how can do it? I read a blog post that explained a core animation scheme to create an iPad flip clock. The problem I have is similar but has important differences. Besides, I not excited about saving the subimage combinations, which I believe can cause a memory issue. Please enlighten me on the possible ways of doing this animation. I am relatively new to iOS programming, so I might have missed obvious ways of doing this animation or effect.

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• Grammatically correct double-noun identifiers, plural versions

  - by Michal Czardybon

  Consider compounds of two nouns, which in natural English would most often appear in the form "noun of noun", e.g. "direction of light", "output of a filter". When programming we usually write "LightDirection" and "FilterOutput". Now, I have a problem with plural nouns. There are two cases: 1) singular of plural e.g. "union of (two) sets", "intersection of (two) segments" Which is correct, SetUnion and SegmentIntersection or SetsUnion and SegmentsIntersection? 2) plural of plural There are two subcases: (a) Many elements, each having many related elements, e.g. "outputs of filters" (b) Many elements, each having single related element, e.g. "directions of vectors" Shell I use FilterOutputs and VectorDirections or FiltersOutputs and VectorsDirections? I suspect correct is the first version (FilterOutupts, VectorDirections), but I think it may lead to ambiguities, e.g. FilterOutputs - many outputs of a single filter or many outputs of many filters? LineSegmentProjections - projections of many segments or many projections of a single segment?

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• General question: Filesystem or database?

  - by poeschlorn

  Hey guys, i want to create a small document management system. there are several users who store their files. each file which is uploaded contains an info which user uploaded it and the document content itself. In a view there are displayed all files of ONE specific user, ordered by date. What would be better: 1) giving the documents a name or metadata(XML) which contain the date and user (and iterate through them to get the metadata) or 2) giving the files a random/unique name and store metadata in a DB? something like this: date | user | filename What would you say and why? The used programming language is java and the DB is MySQL.

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• First and last window don't show up.

  - by SirGregg

  Hi, I'm creating a WinApi application for my programming course. The program is supposed to show an LED clock using a separate window for each 'block'. I have figured most of it out, except for one thing: when creating the two-dimensional array of windows, the first and last window never show up. Here's the piece of code from the InitInstance function: for (int x=0;x<8;x++) for (int y=0;y<7;y++) { digitWnd[x][y] = CreateWindowEx((WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_NOACTIVATE | WS_EX_STATICEDGE), szWindowClass, szTitle, (WS_POPUP| WS_BORDER), NULL, NULL, NULL, NULL, dummyWnd, NULL, hInstance, NULL); ShowWindow(digitWnd[x][y], nCmdShow); UpdateWindow(digitWnd[x][y]); } The same loop bounds are used everytime I interact with the windows (set position and enable/disable). All the windows seem to be working fine, except for digitWnd[0][0] and digitWnd[7][6]... Any ideas as to what is happening?

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• How does compiling circular dependencies work?

  - by Fabio F.

  I've made the example in Java but I think (not tested) that it works in other (all?) languages. You have 2 files. First, M.java: public class MType { XType x; MType() {x = null;} } Second, another file (in the same directory), XType.java: public class XType { MType m; public XType(MType m) {this.m = m;} } Ok it's bad programming, but if you run javac XType it compiles: compiles even MType because XType needs it. But ... MType needs XType ... how does that work? How does the compiler know what is happening? Probably this is a stupid question, but I would like to know how the compiler (javac or any other compilers you know) manages that situation, not how to avoid it. I'm asking because i'm writing a precompiler and I would like to manage that situation.

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• drawbacks of storing all ''things' in a central table

  - by naiquevin

  Hi, I am not sure if there is a term to describe this, but I have observed that content management systems store all kinds of data in a single table with their bare minimum properties while the meta data is stored in another table in form of key value pairs. for eg. everything (blog posts, pages, images, events etc) is stored in one table and considered as a post. I understand that this allows for abstraction and easy extensibility we are considering designing our new project this way. It is not exactly a CMS but we plan to keep adding modules to it in stages. Lets say initially there will be only posts and images on which comments can be posted. Later on we might add videos which will also have the commenting feature. what are the drawbacks of this approach ? and will it work for a requirement like ours ? Thanks

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• What exactly does "adopt a protocol" mean in the Objective-C / Cocoa documentation ?

  - by driis

  I am a C# developer getting started on Objective-C / Cocoa Touch programming. I think I might have gotten some terms wrong because I keep thinking about them "the C# way". Specifically, I have come around the term "protocol" in various documentation and tutorials. In Objective-C, what exactly is a protocol ? Can it be compared to a C# interface ? Is the following declaration the same as saying "The class is implementing the protocol UITextFieldDelegate" ? Or is UITextFieldDelegate to be compared with a generic type parameter in C# ? @interface MyViewController : UIViewController <UITextFieldDelegate> { }

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• What books help one to learn to read code?

  - by Daniel

  Lion's Commentary on Unix Sixth Edition with Source Code is a wonderful book to learn how to read code. Reading code is important -- how does one learn how to write excellent code without having read excellent code? But, sadly, while great writers, of fiction and non-fiction, all spend a great deal of time reading stuff, we, programmers, seem to avoid it like the plague. Worse still, programming books usually go the same way. They might show a pattern or a style, but they often avoid showing good, complex code, and helping one go through it. There are exceptions, of course. I hope. So, with that in mind, what books are to be found which help one learn how to read code?

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• Convert Yes/No/Null from SQL to True/False in a DataTable

  - by Scott Chamberlain

  I have a Sql Database (which I have no control over the schema) that has a Column that will have the varchar value of "Yes", "No", or it will be null. For the purpose of what I am doing null will be handled as No. I am programming in c# net 3.5 using a data table and table adapter to pull the data down. I would like to directly bind the column using a binding source to a check box I have in my program however I do not know how or where to put the logic to convert the string Yes/No/null to boolean True/False; Reading a null from the SQL server and writing back a No on a update is acceptable behavior. Any help is greatly appreciated. EDIT -- This is being developed for windows.

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• Questions about "casting operation" in OOP

  - by rhapsodyn

  When programming, we usually use some type-casting operations. When the casting happens on the objects "on the same level", it feels ok. But when it happens on the ojects "on the different levels"(mainly between father and son), it feels weird. Considering this: Class Son extends Father WhenSon s = (Son)father;, it's absolutely unreasonable. Because a "Son" is not a "Father" anymore, "Son" may grow up with some new properties "Father" doesn't have, the casting operation makes these properties unknown. On the other hand, Father f = (Father)son seems reasonable, but according to LSP "An instance of a derived should be able to replace any instance of its superclass" A "Son" can do anything his "Father" can, so the casting operation seems useless. So can i say that these casting operations are agaisnt OO design principle but necessary?

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• System("pause"); - Why is it wrong?

  - by Faken

  Here's a question that I don't quite understand: The command, System("pause"); is taught to new programmers as a way to pause a program and wait for a keyboard input to continue. However, it seems to be frowned on by many veteran programmers as something that should not be done in varying degrees. Some people say it is fine to use. Some say it is only to be used when you are locked in your room and no one is watching. Some say that they will personally come to your house and kill you if you use it. I, myself am a new programmer with no formal programming training. I use it because I was taught to use it. What I don't understand is that if it is not something to be used, then why was I taught to use it? Or, on the flip side, is it really not that bad after all? What are your thoughts on this subject?

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• Best approach to creating a database driven Java website?

  - by Craig Whitley

  I'm fairly new to programming and new to java, but I'd like to jump in the deep end with a little database driven website project. I've read quite a lot about requirements in the 'real world' requesting experience with Spring and Hibernate, so I have those installed on netbeans and a project created (if I hit run I get the default spring page). Now I just need a little guidance as to where to start designing my app (please tell me if I'm getting in a bit too over my head for a beginner!). Should I start off with my classes? - create all my classes as they map to my database tables and decide which attributes and methods each will require? Can anyone suggest any good books for maybe.. making a java based website from scratch (i.e. from design right through to deployment) that might be useful for a beginner? Any help appreciated thanks.

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• How to start coding the "Dining Philosophers" simulation?

  - by GrizzlyGuru

  I'm not a beginner at C# but I really need to increase my understanding, so I've picked a classic deadlock problem to code to help teach myself some of the more advanced concepts of C#. The Dining Philosophers Problem seems like a good one, but I need a little help to get started. I know I need to approach the "diners" as objects, but to simulate the random delays between eating, should I look to threading with each diner in a separate thread? Do I need some kind of "master" to monitor all the actions? Any general design concept advice is welcome, but I'd like to do the grunt programming as an exercise. Thanks!

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• What is the use of commit messages?

  - by eteubert

  Hi folks, I struggled asking that question but here it is. I am using source control since several years for multiple projects using different systems (svn, hg, git) and I learned how to improve my messages by following guidelines etc. But as far as I can remember I never ever had a look at them afterwards. So ... how do you profit from your own commit messages? When I need to go back because I smashed something and need a fresh start, I usually just go back to the latest "node" (where I started or merged a branch). Do I write those messages just for people monitoring the project who are curious what is going on? Regards

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• Using typedefs (or #defines) on built in types - any sensible reason?

  - by jb

  Well I'm doing some Java - C integration, and throught C library werid type mappings are used (theres more of them;)): #define CHAR char /* 8 bit signed int */ #define SHORT short /* 16 bit signed int */ #define INT int /* "natural" length signed int */ #define LONG long /* 32 bit signed int */ typedef unsigned char BYTE; /* 8 bit unsigned int */ typedef unsigned char UCHAR; /* 8 bit unsigned int */ typedef unsigned short USHORT; /* 16 bit unsigned int */ typedef unsigned int UINT; /* "natural" length unsigned int*/ Is there any legitimate reason not to use them? It's not like char is going to be redefined anytime soon. I can think of: Writing platform/compiler portable code (size of type is underspecified in C/C++) Saving space and time on embedded systems - if you loop over array shorter than 255 on 8bit microprocessor writing: for(uint8_t ii = 0; ii < len; ii++) will give meaureable speedup.

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• Looking for ideas on automatically arranging a set of objects (furniture) in a virtual room in AS3

  - by raf

  First of all, I don't want to visually arrange 3D models dragging them with the mouse, all I want is: Given a room of certain dimensions (L,W,H) and given a set of elements like beds, chairs, etc (with L,W,H dimensions, of course) I want to automatically arrange those elements to take advantage of the space as much as I can. So I want to be able to put as much furniture as I can in a given room. At the end I need to represent the arranged items visually, inside the room. My first thought was to use an array of items and sorting it with array.sortOn(["l","w","h"] Array.NUMERIC) and then define a gap between the objects and make the maths to put the objects one next to another, etc. but that isn't a good approach because some items may be placed on top of another ones (boxes of the same size, boxes on top of tables, etc). I really don't have experience on 3D programming, that's why I'm asking for help. Thanks in advance.

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• Lib Files and Defines

  - by Paul

  I'm using a couple of external libraries and I'd rather not have to include all their source and header files in my main source directory or in my project file. One option would be to compile the libraries as lib files and link them like that. However I'm not sure the defines get evaluated before or after the lib file gets created (which one is it?). If it's before then obviously I can't just pack them because they might not work properly on different compilers or systems. So if I can't pack the libraries as lib files, is there any way for me to link in the c or cpp source files? Probably not, since they would have to be compiled first, but maybe I'm wrong. Edit: Here's a follow-up question, based on answers. Do you think it'd be too much of a hassle to have a makefile that creates the lib files? I'd still rather not add the sources to my project or in my source directory.

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• How to anti-alias the fonts in visual studio in windows forms application?

  - by user1781077

  i want my font to be anti aliased like this so that it looks more professionalenter link description heredoes any one know the code to anti alias the fonts so that the project looks more professional.tell me the code and where to insert it in the project.As of now the fonts looks jaggy the programming language is visual C# 4.0 .net and IDE is VS 2010 for example this is a label1 what do I need to insert to anti alias this.label1.AutoSize = true; this.label1.Font = new System.Drawing.Font("Segoe UI", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.label1.Location = new System.Drawing.Point(189, 187); this.label1.Name = "label1"; this.label1.Size = new System.Drawing.Size(31, 13); this.label1.TabIndex = 0; this.label1.Text = "from";

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• Android how to call a method of MainActivity in SmsReceiver Class

  - by GeneticSmart

  I'm very new to Android Programming, It would be really great if someone can help me in this.My project contains two JAVA files. MainActivity.java extends Activity SMSReceiver.java extends Broadcastreceiver The SMSreceiver.java has the code which displays any incoming SMS in toast. Can you please tell me how to call a function in MainActivity whenever a particular SMS is received. For eg: when I receive sms called as starttemp it should call a function starttemp. I have searched a lot and found that intents are a way to do this and we cannot call these methods directly. Please can anyone help me in this? And it would be really great if someone can send me working code.

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• Transfer of directory structure over network

  - by singh

  I am designing a remote CD/DVD burner to address hardware constraints on my machine. My design works like this: (analogous to a network printer) Unix-based machine (acts as server) hosts a burner. Windows-based machine acts as client. Client prepares data to burn and transfers it to the server. Server burns the data on CD/DVD. My question is: what is the best protocol to transfer data over the network (Keeping the same directory hierarchy) between different operating systems?

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• Some Simple Questions for knowledge?

  - by dhaliwaljee

  Before Some days my friend ask me some simple questions, but I have no answer. Please tell me about these questions. How many computer programming languages are used all in the world ? I want to create a language like 'java or c#'. What is the procedure for creating a language and how it will create? Which language is used for manipulate Window operating system? What is the procedure of create Operating System like Windows/Linux/Mac and in which language it should create? What is the procedure of create open source framework project in javascript and php?

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• Converting digits, generated by weblog service, to Arabic form

  - by Sorush Rabiee

  sorry if this is irrelevance :-) I need to write something in my html code to convert digits of form 0123456789 to ?????????? (Persian digits uni06F0..uni06F9). the number of visitors is generated by blog service. and I want to convert its digits to Arabic. Counter: ????? ????????????? : <BlogSky:Weblog Counter /> ??? the Persian part of above code mean 'Number of visitors' and 'Persons' (from left to right). but digits are represented in latin (0123...). Is it possible to write something like a function in html? i want it to be a global one for using in weblogs. Note: I don't know anything about web programming languages. I'm not sure about language of above code. (html?)

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• Java: How can I create good looking class docs with Javadoc?

  - by Cheeso

  I'd like to create HTNML documentation for a Java class library that includes programming guide information - beyond just a class reference code examples in the reference doc collapsible regions I want it to look well-styled. Something like this: I think that Javadoc exposes a doclet API that allows other parties to provide doc generation integrated in Javadoc. Is there a doclet option that I can use (for free) that does something a little nicer than the standard javadoc output? I tried googling for this but no luck. Suggestions?

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• In Flash Actionscript 3.0 how do I create smooth keyboard controls for player movement?

  - by Reid

  I am a beginner in Flash Actionscript 3.0 programming. I am trying to create smooth keyboard controls for player movement in a game. I'm currently using addEventListener(KeyboardEvent.KEY_DOWN) listening for a keyboard key press and then within the handler function moving a graphic by adding a number to its .x or .y property. This creates a slow, sluggish jerk at the beginning. I know there's a smoother, more responsive way to do this but have no idea where to begin. Any help would be appreciated!

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