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  • SQL SERVER – Get Date and Time From Current DateTime – SQL in Sixty Seconds #025 – Video

    - by pinaldave
    This is 25th video of series SQL in Sixty Seconds we started a few months ago. Even though this is 25th video it seems like we have just started this few days ago. The best part of this SQL in Sixty Seconds is that one can learn something new in less than sixty seconds. There are many concepts which are not new for many but just we all have 60 seconds to refresh our memories. In this video I have touched a very simple question which I receive very frequently on this blog. Q1) How to get current date time? Q2) How to get Only Date from datetime? Q3) How to get Only Time from datetime? I have created a sixty second video on this subject and hopefully this will help many beginners in the SQL Server field. This sixty second video describes the same. Here is a similar script which I have used in the video. SELECT GETDATE() GO -- SQL Server 2000/2005 SELECT CONVERT(VARCHAR(8),GETDATE(),108) AS HourMinuteSecond, CONVERT(VARCHAR(8),GETDATE(),101) AS DateOnly; GO -- SQL Server 2008 Onwards SELECT CONVERT(TIME,GETDATE()) AS HourMinuteSeconds; SELECT CONVERT(DATE,GETDATE()) AS DateOnly; GO Related Tips in SQL in Sixty Seconds: Retrieve Current Date Time in SQL Server CURRENT_TIMESTAMP, GETDATE(), {fn NOW()} Get Time in Hour:Minute Format from a Datetime – Get Date Part Only from Datetime Get Current System Date Time Get Date Time in Any Format – UDF – User Defined Functions Date and Time Functions – EOMONTH() – A Quick Introduction DATE and TIME in SQL Server 2008 I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Image Credit: Movie Gone in 60 Seconds Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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  • DirectX9 / HLSL Shader Model 3 - Passing Doubles between Shaders

    - by P. Avery
    I need higher precision on a few values within my vertex and pixel shaders...I'm currently using floats, so I would like to use doubles...I've read that HLSL Model 4 has two functions to convert a double into two unsigned integers and back again( asuint() and asdouble() ). These functions are only supported on HLSL 4 and I am using DirectX 9 which will only compile HLSL Model 3 and below... How can I pass a double between shaders? here is implementation for HLSL 4: struct VS_INPUT { float2 v; }; struct PS_INPUT { uint a; uint b; uint c; uint d; }; PS_INPUT VertexShader( VS_INPUT Input ) { PS_INPUT Output = ( PS_INPUT )0; double2 vPos = mul( Input.v, mWorld ).xy; asuint( vPos.x, Output.a, Output.b ); asuint( vPos.y, Output.c, Output.d ); return Output; } float4 PixelShader( PS_INPUT Input ) { double2 vPos; vPos.x = asdouble( Input.a, Input.b ); vPos.y = asdouble( Input.c, Input.d ); ... return 1; }

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  • PHP Browser Game Question - Pretty General Language Suitability and Approach Question

    - by JimBadger
    I'm developing a browser game, using PHP, but I'm unsure if the way I'm going about doing it is to be encouraged anymore. It's basically one of those MMOs where you level up various buildings and what have you, but, you then commit some abstract fighting entity that the game gives you, to an automated battle with another player (producing a textual, but hopefully amusing and varied combat report). Basically, as soon as two players agree to fight, PHP functions on the "fight.php" page run queries against a huge MySQL database, looking up all sorts of complicated fight moves and outcomes. There are about three hundred thousand combinations of combat stance, attack, move and defensive stances, so obviously this is quite a resource hungry process, and, on the super cheapo hosted server I'm using for development, it rapidly runs out of memory. The PHP script for the fight logic currently has about a thousand lines of code in it, and I'd say it's about half-finished as I try to add a bit of AI into the fight script. Is there a better way to do something this massive than simply having some functions in a PHP file calling the MySQL Database? I taught myself a modicum of PHP a while ago, and most of the stuff I read online (ages ago) about similar games was all PHP-based. but a) am I right to be using PHP at all, and b) am I missing some clever way of doing things that will somehow reduce server resource requirements? I'd consider non PHP alternatives but, if PHP is suitable, I'd rather stick to that, so there's no overhead of learning something new. I think I'd bite that bullet if it's the best option for a better game, though.

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  • Quick Outline: Navigating Your PL/SQL Packages in Oracle SQL Developer

    - by thatjeffsmith
    If you’re browsing your packages using the Connections panel, you have a nice tree navigator to click around your packages and your variable, procedure, and functions. Click, click, click all day long, click, click, click while I sing this song… But What if you drill into your PL/SQL source from the worksheet and don’t have the Tree expanded? Let’s say you’re working on your script, something like - Hmm, what goes next again? So I need to reacquaint myself with just what my beer package requires, so I’m going to drill into it by doing a DESCRIBE (via SHIFT+F4), and now I have the package open. The package is open but the tree hasn’t auto-expanded. Please don’t tell me I have to do the click-click-click thing in the tree!?! Just Open the Quick Outline Panel Do you see it? Just right click in the procedure editor – select the ‘Quick Outline’ in the context menu, and voila! The navigational power of the tree, without needing to drill down the tree itself. If I want to drill into my procedure declaration, just click on said procedure name in the Quick Outline panel. This works for both package specs and bodies. Technically you can use this for stand alone procedures and functions, but the real power is demonstrated for packages.

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  • Differentiate procedural language(c) from oop languages(c++)

    - by niko
    I have been trying to differentiate c and c++(or oop languages) but I don't understand where the difference is. Note I have never used c++ but I asked my friends and some of them to differentiate c and c++ They say c++ has oop concepts and also the public, private modes for definition of variables and which c does not have though. Seriously I have done vb.net programming for a while 2 to 3 months, I never faced a situation to use class concepts and modes of definition like public and private. So I thought what could be the use for these? My friend explained me a program saying that if a variable is public, it can be accessed anywhere I said why not declare it as a global variable like in c? He did not get back to my question and he said if a variable is private it cannot be accessed by some other functions I said why not define it as a local variable, even these he was unable to answer. No matter where I read private variables cannot be accessed whereas public variables can be then why not make public as global and private as local whats the difference? whats the real use of public and private ? please don't say it can be used by everyone, I suppose why not we use some conditions and make the calls? I have heard people saying security reasons, a friend said if a function need to be accessed it should be inherited first. He explained saying that only admin should be able to have some rights and not all so that functions are made private and inherited only by the admin to use Then I said why not we use if condition if ( login == "admin") invoke the function he still did not answer these question. Please clear me with these things, I have done vb.net and vba and little c++ without using oop concepts because I never found their real use while I was writing the code, I'm a little afraid am I too back in oop concepts?

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  • HTML5 point and click adventure game code structure with CreateJS

    - by user1612686
    I'm a programming beginner. I made a tiny one scene point and click adventure game to try to understand simple game logic and came up with this: CreateJS features prototypes for creating bitmap images, sprites and sounds objects. I create them and define their properties in a corresponding function (for example images(); spritesheets(), sounds()...). I then create functions for each animation sequence and "game level" functions, which handle user interactions and play the according animations and sounds for a certain event (when the level is complete, the current level function calls the next level function). And I end up with quite the mess. What would be the "standard (if something like that exists)" OOP approach to structure simple game data and interactions like that? I thought about making game.images, game.sprites, game.sounds objects, which contain all the game data with its properties using CreateJS constructors. game.spriteAnimations and game.tweenAnimations objects for sprite animations and tweens and a game.levelN object, which communicates with a game.interaction object, processing user interaction. Does this make any sense? How do you structure your simple game code? Thanks in advance!

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  • How much Ruby should I learn before moving to Rails?

    - by Kevin
    Just a quick question.. I can never get a definitive answer when googling this, either. Some people say you can learn Rails without knowing any Ruby, but at some point you'll run into a brick wall and wish you knew Ruby and will have to go back to learn it..and some say to learn the "basics" of Ruby before learning Rails and it will make your life that much easier.. My current knowledge is low. I'm not a beginner, but I'm not pro, either. I went through the Learn Python The Hard Way online book in about a month, but I stopped once I got to the OOP side of Python (I know booleans, elif/if/else/statements, for loops, while loops, functions) I agree with learning the "basics" of Ruby before learning Rails, but what exactly are the "basics" of Ruby? Would I need to learn the whole OOP side of Ruby before I went on to Rails? Or would I just need to learn the Ruby syntax up to where I learned Python (booleans, elif/if/else/statements, for loops, while loops, functions) before I went on to Rails? Thanks!

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  • JavaScript objects and Crockford's The Good Parts

    - by Jonathan
    I've been thinking quite a bit about how to do OOP in JS, especially when it comes to encapsulation and inheritance, recently. According to Crockford, classical is harmful because of new(), and both prototypal and classical are limited because their use of constructor.prototype means you can't use closures for encapsulation. Recently, I've considered the following couple of points about encapsulation: Encapsulation kills performance. It makes you add functions to EACH member object rather than to the prototype, because each object's methods have different closures (each object has different private members). Encapsulation forces the ugly "var that = this" workaround, to get private helper functions to have access to the instance they're attached to. Either that or make sure you call them with privateFunction.apply(this) everytime. Are there workarounds for either of two issues I mentioned? if not, do you still consider encapsulation to be worth it? Sidenote: The functional pattern Crockford describes doesn't even let you add public methods that only touch public members, since it completely forgoes the use of new() and constructor.prototype. Wouldn't a hybrid approach where you use classical inheritance and new(), but also call Super.apply(this, arguments) to initialize private members and privileged methods, be superior?

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  • SQLAuthority News – #SQLPASS 2012 Book Signing Photos

    - by pinaldave
    I am at SQLPASS 2012 and the event is going great. Here are few of the random photos and random news. We had participated in three different book signing event today. SQL Queries 2012 Joes 2 Pros Book 1 Launch and Book Signing SQL 2012 Functions Book Launch at Embarcadero SQL Backup and Recovery Book Launch at Idera Rick Morelan and I authored the first two books 1) SQL 2012 Functions and 2) SQL Queries 2012 Joes 2 Pros Volume 1. Our dear friend Tim Randney authored SQL Backup and Recovery Book. In the book signing event of Tim Radney I went ahead of the time and stood in the line. I was fortunate to receive the very first copy of the autographed book from Tim Radney. We have one more book signing event of the book SQL Backup and Recovery by Tim Randey on Friday 9, 2012 between 12 to 1 PM at Joes 2 Pros booth #117. This is your last chance to shake hands with us and meet us in person. Reference: Pinal Dave (http://blog.sqlauthority.com)   Filed under: PostADay, SQL, SQL Authority, SQL PASS, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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  • Is there any reason not to go directly from client-side Javascript to a database?

    - by Chris Smith
    So, let's say I'm going to build a Stack Exchange clone and I decide to use something like CouchDB as my backend store. If I use their built-in authentication and database-level authorization, is there any reason not to allow the client-side Javascript to write directly to the publicly available CouchDB server? Since this is basically a CRUD application and the business logic consists of "Only the author can edit their post" I don't see much of a need to have a layer between the client-side stuff and the database. I would simply use validation on the CouchDB side to make sure someone isn't putting in garbage data and make sure that permissions are set properly so that users can only read their own _user data. The rendering would be done client-side by something like AngularJS. In essence you could just have a CouchDB server and a bunch of "static" pages and you're good to go. You wouldn't need any kind of server-side processing, just something that could serve up the HTML pages. Opening my database up to the world seems wrong, but in this scenario I can't think of why as long as permissions are set properly. It goes against my instinct as a web developer, but I can't think of a good reason. So, why is this a bad idea? EDIT: Looks like there is a similar discussion here: Writing Web "server less" applications EDIT: Awesome discussion so far, and I appreciate everyone's feedback! I feel like I should add a few generic assumptions instead of calling out CouchDB and AngularJS specifically. So let's assume that: The database can authenticate users directly from its hidden store All database communication would happen over SSL Data validation can (but maybe shouldn't?) be handled by the database The only authorization we care about other than admin functions is someone only being allowed to edit their own post We're perfectly fine with everyone being able to read all data (EXCEPT user records which may contain password hashes) Administrative functions would be restricted by database authorization No one can add themselves to an administrator role The database is relatively easy to scale There is little to no true business logic; this is a basic CRUD app

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  • C IDE for Mac needed

    - by StasM
    I'm looking for heavy-duty C/C++ IDE for Mac that would satisfy the following criteria: Work with big projects (~5000 files, some of them 100K big) efficiently. Have good navigation both file-based and symbol-based - i.e. "go to file", "go to function" etc. with autocompletion support. Support for "go to declaration/definition" for symbols - functions, structures, etc. Auto-adding new files in folders already in the project. Support for code completion for values, function names, etc. At least rudimentary CPP macro understanding - i.e. #define foo bar then foo() should take me either to #define or to actual bar. I understand full CPP parsing may be hard, but I hope for at least the obvious cases. Support for displaying parameter names/types by function name, preferably - integrated with the previous item, for functions defined in the project. Support for libc would be nice too :) (optional) Cross-project search support (I can manage with grep -r if everything else works) (optional) SVN support, at least to some extent (update, commit, mark updated) Is there such editor around? Free would be nice, but I'm ready to part with some money if it's good enough. I'm using TextMate now but I'm not satisfied with it. Tried Xcode but it seems to not be able to handle a large project - it just crashed...

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  • SQL Server Interview Questions

    - by Rodney Vinyard
    User-Defined Functions Scalar User-Defined Function A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. Table-Value User-Defined Function An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables. Multi-statement Table-Value User-Defined Function A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a T-SQL select command or a group of them gives us the capability to in essence create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, I can use it in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets.

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  • How to write a very basic compiler [closed]

    - by Ali
    Possible Duplicate: Best Online resources to learn about Compilers? What would be the best way to learn about compilers, and executable formats? Advanced compilers like gcc compile codes into machine readable files according to the language in which the code has been written (e.g. C, C++, etc). In fact, they interpret the meaning of each codes according to library and functions of the corresponding languages. Correct me if I'm wrong. I wish to better understand compilers by writing a very basic compiler (probably in C) to compile a static file (e.g. Hello World in a text file). I tried some tutorials and books, but all of them are for practical cases. They deal with compiling dynamic codes with meanings connected with the corresponding language. How can I write a basic compiler to convert a static text into a machine readable file? The next step will be introducing variables into the compiler; imagine that we want to write a compiler which compile only some functions of a language. Introducing practical tutorials and resources is highly appreciated :-)

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  • How to use shared_ptr for COM interface pointers

    - by Seefer
    I've been reading about various usage advice relating to the new c++ standard smart pointers unique_ptr, shared_ptr and weak_ptr and generally 'grok' what they are about when I'm writing my own code that declares and consumes them. However, all the discussions I've read seem restricted to this simple usage situation where the programmer is using smart in his/her own code, with no real discussion on techniques when having to work with libraries that expect raw pointers or other types of 'smart pointers' such as COM interface pointers. Specifically I'm learning my way through C++ by attempting to get a standard Win32 real-time game loop up and running that uses Direct2D & DirectWrite to render text to the display showing frames per second. My first task with Direct2D is in creating a Direct2D Factory object with the following code from the Direct2D examples on MSDN: ID2D1Factory* pD2DFactory = nullptr; HRESULT hr = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &pD2DFactory); pD2DFactory is obviously an 'out' parameter and it's here where I become uncertain how to make use of smart pointers in this context, if indeed it's possible. My inexperienced C++ mind tells me I have two problems: With pD2DFactory being a COM interface pointer type, how would smart_ptr work with the Add() / Release() member functions for a COM object instance? Are smart pointers able to be passed to functions in situations where the function is using an 'out' pointer parameter technique? I did experiment with the alternative of using _com_ptr_t in the comip.h header file to help with pointer lifetime management and declared the pD2DFactory pointer with the following code: _com_ptr_t<_com_IIID<pD2DFactory, &__uuidof(pD2DFactory)>> pD2DFactory = nullptr; and it appears to work so far but, as you can see, the syntax is cumbersome :) So, I was wondering if any C++ gurus here could confirm whether smart pointers are able to help in cases like this and provide examples of usage, or point me to more in-depth discussions of smart pointer usage when needing to work with other code libraries that know nothing of them. Or is it simply a case of my trying to use the wrong tool for the job? :)

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  • Haskell: Best tools to validate textual input?

    - by Ana
    In Haskell, there are a few different options to "parsing text". I know of Alex & Happy, Parsec and Attoparsec. Probably some others. I'd like to put together a library where the user can input pieces of a URL (scheme e.g. HTTP, hostname, username, port, path, query, etc.) I'd like to validate the pieces according to the ABNF specified in RFC 3986. In other words, I'd like to put together a set of functions such as: validateScheme :: String -> Bool validateUsername :: String -> Bool validatePassword :: String -> Bool validateAuthority :: String -> Bool validatePath :: String -> Bool validateQuery :: String -> Bool What is the most appropriate tool to use to write these functions? Alex's regexps is very concise, but it's a tokenizer and doesn't straightforwardly allow you to parse using specific rules, so it's not quite what I'm looking for, but perhaps it can be wrangled into doing this easily. I've written Parsec code that does some of the above, but it looks very different from the original ABNF and unnecessarily long. So, there must be an easier and/or more appropriate way. Recommendations?

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  • How can I improve my error checking and handling?

    - by Google
    Lately I have been struggling to understand what the right amount of checking is and what the proper methods are. I have a few questions regarding this: What is the proper way to check for errors (bad input, bad states, etc)? Is it better to explicitly check for errors, or use functions like asserts which can be optimized out of your final code? I feel like explicitly checking clutters a program with a lot of extra code which shouldn't be executed in most situations anyway-- and not to mention most errors end up with an abort/exit failure. Why clutter a function with explicit checks just to abort? I have looked for asserts versus explicit checking of errors and found little to truly explain when to do either. Most say 'use asserts to check for logic errors and use explicit checks to check for other failures.' This doesn't seem to get us very far though. Would we say this is feasible: Malloc returning null, check explictly API user inserting odd input for functions, use asserts Would this make me any better at error checking? What else can I do? I really want to improve and write better, 'professional' code.

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  • PHP: A config file in .ini or .php format?

    - by Tim Visee
    I'm working on a huge CMS system, and I asked myself what configuration format I should use. There are two common formats for configuration files. The first one is an INI file, containg all the configuration properties. Then you can simply parse this INI file using build in PHP functions. A second option is to use a PHP file containing a regular PHP array with these configuration properties. Now, it's easier to edit an INI file, but a PHP file give's you more options, for example it allows you to add a function which retrieves one of the configuration options while reading the configuration file. Note: The PHP configuration file would only contain an array of configuration, no initialization functions or anything. (This is possible of course, but it's not implemented by default) Now, what is recommend for me to use as configuration file? What is the most common format for a configuration file? Should I go for simplicity with the INI files, or with a more dynamic one using PHP. One thing to note, this is not for personal usage. I'm planning to release the CMS system soon, and a lot of websites are scheduled already to change to my CMS system.

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  • What is a widely accepted term for a string variable that would probably contain a file path and file name?

    - by Peter Turner
    For functions that need to index files in a directory and rename them FileName0001, FileName0002, etc... I often need to write a function that splits the file name from the file path and rename the file. When I put the file name and file path back together, I don't have a very good name for the variable that contains both of them and I usually just wind up concatenating them every time I want to use them (usually using them as parameters for functions labeled either filename or filepath) so I never really know what I'm doing until I notice a lot of files being written in the same directory as my binaries. Anyway, what do I call a file name and a file path? I don't want to call it File, because that usually means the binary information behind the file. I don't want to call it URI because that usually means I've got some sort of protocol, which I don't. I just want a good way to denote "c:\somedir\somedir\somedir\somefile.txt" so as to deconfuse this mess I've just realized I'm in. Please don't just list your personal preference. I think an excellent answer should "'site its sources". (as in, provide a link to a repository with a good example of the code being used as I described)

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  • Is LINQ to objects a collection of combinators?

    - by Jimmy Hoffa
    I was just trying to explain the usefulness of combinators to a colleague and I told him LINQ to objects are like combinators as they exhibit the same value, the ability to combine small pieces to create a single large piece. Though I don't know that I can call LINQ to objects combinators. I've seen 2 levels of definition for combinator that I generalize as such: A combinator is a function which only uses things passed to it A combinator is a function which only uses things passed to it and other standard atomic functions but not state The first is very rigid and can be seen in the combinatory calculus systems and in haskell things like $ and . and various similar functions meet this rule. The second is less rigid and would allow something like sum as it uses the + function which was not passed in but is standard and not stateful. Though the LINQ extensions in C# use state in their iteration models, so I feel I can't say they're combinators. Can someone who understands the definition of a combinator more thoroughly and with more experience in these realms give a distinct ruling on this? Are my definitions of 'combinator' wrong to begin with?

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  • New way of integrating Openfeint in Cocos2d-x 0.12.0

    - by Ef Es
    I am trying to implement OpenFeint for Android in my cocos2d-x project. My approach so far has been creating a button that calls a static java method in class Bridge using jnihelper functions (jnihelper only accepts statics). Bridge has one singleton attribute of type OFAndroid, that is the class dynamically calling the Openfeint Api methods, and every method in the bridge just forwards it to the OFAndroid object. What I am trying to do now is to initialize the openfeint libraries in the main java class that is the one calling the static C++ libraries. My problem right now is that the initializing function void com.openfeint.api.OpenFeint.initialize(Context ctx, OpenFeintSettings settings, OpenFeintDelegate delegate) is not accepting the context parameter that I am giving him, which is a "this" reference to the main class. Main class extends from Cocos2dxActivity but I don't have any other that extends from Application. Any suggestions on fixing it or how to improve the architecture? EDIT: I am trying a new solution. Make the bridge class into an Application child, is called from Main object, initializes OpenFeint when created and it can call the OpenFeint functions instead of needing an additional class. The problem is I still get the error. 03-30 14:39:22.661: E/AndroidRuntime(9029): Caused by: java.lang.NullPointerException 03-30 14:39:22.661: E/AndroidRuntime(9029): at android.content.ContextWrapper.getPackageManager(ContextWrapper.java:85) 03-30 14:39:22.661: E/AndroidRuntime(9029): at com.openfeint.internal.OpenFeintInternal.validateManifest(OpenFeintInternal.java:885) 03-30 14:39:22.661: E/AndroidRuntime(9029): at com.openfeint.internal.OpenFeintInternal.initializeWithoutLoggingIn(OpenFeintInternal.java:829) 03-30 14:39:22.661: E/AndroidRuntime(9029): at com.openfeint.internal.OpenFeintInternal.initialize(OpenFeintInternal.java:852) 03-30 14:39:22.661: E/AndroidRuntime(9029): at com.openfeint.api.OpenFeint.initialize(OpenFeint.java:47) 03-30 14:39:22.661: E/AndroidRuntime(9029): at nurogames.fastfish.NuroFeint.onCreate(NuroFeint.java:23) 03-30 14:39:22.661: E/AndroidRuntime(9029): at nurogames.fastfish.FastFish.onCreate(FastFish.java:47) 03-30 14:39:22.661: E/AndroidRuntime(9029): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1069) 03-30 14:39:22.661: E/AndroidRuntime(9029): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2751)

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  • Explanation on how "Tell, Don't Ask" is considered good OO

    - by Pubby
    This blogpost was posted on Hacker News with several upvotes. Coming from C++, most of these examples seem to go against what I've been taught. Such as example #2: Bad: def check_for_overheating(system_monitor) if system_monitor.temperature > 100 system_monitor.sound_alarms end end versus good: system_monitor.check_for_overheating class SystemMonitor def check_for_overheating if temperature > 100 sound_alarms end end end The advice in C++ is that you should prefer free functions instead of member functions as they increase encapsulation. Both of these are identical semantically, so why prefer the choice that has access to more state? Example 4: Bad: def street_name(user) if user.address user.address.street_name else 'No street name on file' end end versus good: def street_name(user) user.address.street_name end class User def address @address || NullAddress.new end end class NullAddress def street_name 'No street name on file' end end Why is it the responsibility of User to format an unrelated error string? What if I want to do something besides print 'No street name on file' if it has no street? What if the street is named the same thing? Could someone enlighten me on the "Tell, Don't Ask" advantages and rationale? I am not looking for which is better, but instead trying to understand the author's viewpoint.

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  • Gödel, Escher, Bach - Gödel's string

    - by Brad Urani
    In the book Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter, the author gives us a representation of the precursor to Gödel's string (Gödel's string's uncle) as: ~Ea,a': (I don't have the book in front of me but I think that's right). All that remains to get Gödel's string is to plug the Gödel number for this string into the free variable a''. What I don't understand is how to get the Gödel number for the functions PROOF-PAIR and ARITHMOQUINE. I understand how to write these functions in a programming language like FlooP (from the book) and could even write them myself in C# or Java, but the scheme that Hofstadter defines for Gödel numbering only applies to TNT (which is just his own syntax for natural number theory) and I don't see any way to write a procedure in TNT since it doesn't have any loops, variable assignments etc. Am I missing the point? Perhaps Gödel's string is not something that can actually be printed, but rather a theoretical string that need not actually be defined? I thought it would be neat to write a computer program that actually prints Gödel's string, or Gödel's string encoded by Gödel numbering (yes, I realize it would have a gazillion digits) but it seems like doing so requires some kind of procedural language and a Gödel numbering system for that procedural language that isn't included in the book. Of course once you had that, you could write a program that plugs random numbers into variable "a" and run procedure PROOF-PAIR on it to test for theoromhood of Gödel's string. If you let it run for a trillion years you might find a derivation that proves Gödel's string.

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  • Best practices for using namespaces in C++.

    - by Dima
    I have read Uncle Bob's Clean Code a few months ago, and it has had a profound impact on the way I write code. Even if it seemed like he was repeating things that every programmer should know, putting them all together and putting them into practice does result in much cleaner code. In particular, I found breaking up large functions into many tiny functions, and breaking up large classes into many tiny classes to be incredibly useful. Now for the question. The book's examples are all in Java, while I have been working in C++ for the past several years. How would the ideas in Clean Code extend to the use of namespaces, which do not exist in Java? (Yes, I know about the Java packages, but it is not really the same.) Does it make sense to apply the idea of creating many tiny entities, each with a clearly define responsibility, to namespaces? Should a small group of related classes always be wrapped in a namespace? Is this the way to manage the complexity of having lots of tiny classes, or would the cost of managing lots of namespaces be prohibitive?

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  • Creating a Website Without a Framework [closed]

    - by James Jeffery
    I've been using PHP Frameworks for so long that I've actually forgot the "best practices" for create websites without one. Usually I will use Symfony, or more recently I've been using Laravel. A client wants a very simple website, but with certain parts of it dynamic. Due to the nature of the site using Wordpress, or a Framework, is out of the question. I'm a sucker for priding myself on my code, but I feel like I'm asking such a basic question that it's killing me to ask. But, what are the best practices for creating websites without a Framework? I like to live by the K.I.S.S (Keep It Simple Stupid!) method of thinking. So, my idea was to just create the .php pages that are required, do any page processing or database interaction on that page, then have the HTML below the closing PHP tag. I would have any helpers/functions in a functions.php file. This is what I remember doing way before I was using Frameworks, and to me it seems like a very old school way of doing things. I've not created a site without a Framework for literally 2+ years, so I've lost my way with the basics. Any advice would be greatly appreciated.

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  • C# vector class - Interpolation design decision

    - by Benjamin
    Currently I'm working on a vector class in C# and now I'm coming to the point, where I've to figure out, how i want to implement the functions for interpolation between two vectors. At first I came up with implementing the functions directly into the vector class... public class Vector3D { public static Vector3D LinearInterpolate(Vector3D vector1, Vector3D vector2, double factor) { ... } public Vector3D LinearInterpolate(Vector3D other, double factor { ... } } (I always offer both: a static method with two vectors as parameters and one non-static, with only one vector as parameter) ...but then I got the idea to use extension methods (defined in a seperate class called "Interpolation" for example), since interpolation isn't really a thing only available for vectors. So this could be another solution: public class Vector3D { ... } public static class Interpolation { public static Vector3D LinearInterpolate(this Vector3D vector, Vector3D other, double factor) { ... } } So here an example how you'd use the different possibilities: { var vec1 = new Vector3D(5, 3, 1); var vec2 = new Vector3D(4, 2, 0); Vector3D vec3; vec3 = vec1.LinearInterpolate(vec2, 0.5); //1 vec3 = Vector3D.LinearInterpolate(vec1, vec2, 0.5); //2 //or with extension-methods vec3 = vec1.LinearInterpolate(vec2, 0.5); //3 (same as 1) vec3 = Interpolation.LinearInterpolation(vec1, vec2, 0.5); //4 } So I really don't know which design is better. Also I don't know if there's an ultimate rule for things like this or if it's just about what someone personally prefers. But I really would like to hear your opinions, what's better (and if possible why ).

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