first class functions - Page 50

which should be drawn first , class or sequence diagram?

- by m0j1

hi , I've had this discussion with my professor at college about UML diagrams . hi believes that sequence diagrams should be drawn before getting to class diagrams . but I think the opposite . I think after finishing the usecase diagram , the next diagram should be class diagram and after that we should get to sequence diagram . Rational rose requires us to use the classes in sequence diagram, which are already in class diagram . can anyone help me with this? thanks

Read the article

How to define a static array without a contant size in a constructor of a class? (C++)

- by Keand64

I have a class defined as: class Obj { public: int width, height; Obj(int w, int h); } and I need it to contain a static array like so: int presc[width][height]; however, I cannot define within the class, so it it possible to create a pointer to a 2D array (and, out of curiosity, 3, 4, and 5D arrays), have that as a member of the class, and intitalize it in the constructor like: int ar[5][6]; Obj o(5, 6, &ar); If that isn't possible, is there any way to get a static array without a contant size in a class, or am I going to have to use a dynamic array? (Something I don't want to do because I don't plan on ever changing the size of the array after it's created.)

Read the article

Django: Can class-based views accept two forms at a time?

- by Hooman

If I have two forms: class ContactForm(forms.Form): name = forms.CharField() message = forms.CharField(widget=forms.Textarea) class SocialForm(forms.Form): name = forms.CharField() message = forms.CharField(widget=forms.Textarea) and wanted to use a class based view, and send both forms to the template, is that even possible? class TestView(FormView): template_name = 'contact.html' form_class = ContactForm It seems the FormView can only accept one form at a time. In function based view though I can easily send two forms to my template and retrieve the content of both within the request.POST back. variables = {'contact_form':contact_form, 'social_form':social_form } return render(request, 'discussion.html', variables) Is this a limitation of using class based view (generic views)? Many Thanks

Read the article

Why does this code generate an error? [closed]

- by user559601

Read the article

python function that returns a function from list of functions

- by thkang

I want to make following function: 1)input is a number. 2)functions are indexed, return a function whose index matches given number here's what I came up with: def foo_selector(whatfoo): def foo1(): return def foo2(): return def foo3(): return ... def foo999(): return #something like return foo[whatfoo] the problem is, how can I index the functions (foo#)? I can see functions foo1 to foo999 by dir(). however, dir() returns name of such functions, not the functions themselves. In the example, those foo-functions aren't doing anything. However in my program they perform different tasks and I can't automatically generate them. I write them myself, and have to return them by their name.

Read the article

In Entity framework, we can use Model first, DB first, Code first but how can we create table programmatically

- by AukI

In entity framework we can use 3 approaches model first , code first , database first but each one of them needs manual hand touch(means creating database or create model or write the POCO class codes or entity class codes) before proceeding to the next step ( using EF in context ). What if I want to create database and tables and table relationships programatically and still want to have to features of EntityFramework 4.3. To be more specific , from this example http://support.microsoft.com/kb/307283 we can create database , tables and everything using SQL command but we can't have the advantages of entity framework. So if we want to have that what should we do?

Read the article

How do I make lambda functions generic in Scala?

- by Electric Coffee

As most of you probably know you can define functions in 2 ways in scala, there's the 'def' method and the lambda method... making the 'def' kind generic is fairly straight forward def someFunc[T](a: T) { // insert body here what I'm having trouble with here is how to make the following generic: val someFunc = (a: Int) => // insert body here of course right now a is an integer, but what would I need to do to make it generic? val someFunc[T] = (a: T) => doesn't work, neither does val someFunc = [T](a: T) => Is it even possible to make them generic, or should I just stick to the 'def' variant?

Read the article

Difference between Class Abstraction and Object Interfaces in PHP?

- by Mark Tomlin

What is the difference between a Class Abstraction and an Object Interfaces in PHP? I ask because, I don't really see the point to both of them, they both do the same thing! So, what are the advantages of disadvantages using both against one or the other? Class Abstraction: abstract class aClass { // Force extending class to define these methods abstract public function setVariable($name, $var); abstract public function getHtml($template); } Object Interface: interface iClass { // Force impementing class to define these methods public function setVariable($name, $var); public function getHtml($template); }

Read the article

Can pydoc/help() hide the documentation for inherited class methods and attributes?

- by EOL

When declaring a class that inherits from a specific class: class C(dict): added_attribute = 0 the documentation for class C lists all the methods of dict (either through help(C) or pydoc). Is there a way to hide the inherited methods from the automatically generated documentation (the documentation string can refer to the base class, for non-overwritten methods)? or is it impossible? This would be useful: pydoc lists the functions defined in a module after its classes. Thus, when the classes have a very long documentation, a lot of less than useful information is printed before the new functions provided by the module are presented, which makes the documentation harder to exploit (you have to skip all the documentation for the inherited methods until you reach something specific to the module being documented).

Read the article

Origin of common list-processing function names

- by Heatsink

Some higher-order functions for operating on lists or arrays have been repeatedly adopted or reinvented. The functions map, fold[l|r], and filter are found together in several programming languages, such as Scheme, ML, and Python, that don't seem to have a common ancestor. I'm going with these three names to keep the question focused. To show that the names are not universal, here is a sampling of names for equivalent functionality in other languages. C++ has transform instead of map and remove_if instead of filter (reversing the meaning of the predicate). Lisp has mapcar instead of map, remove-if-not instead of filter, and reduce instead of fold (Some modern Lisp variants have map but this appears to be a derived form.) C# uses Select instead of map and Where instead of filter. C#'s names came from SQL via LINQ, and despite the name changes, their functionality was influenced by Haskell, which was itself influenced by ML. The names map, fold, and filter are widespread, but not universal. This suggests that they were borrowed from an influential source into other contemporary languages. Where did these function names come from?

Read the article

The idea of functionN in Scala / Functionaljava

- by Luke Murphy

From brain driven development It turns out, that every Function you’ll ever define in Scala, will become an instance of an Implementation which will feature a certain Function Trait. There is a whole bunch of that Function Traits, ranging from Function1 up to Function22. Since Functions are Objects in Scala and Scala is a statically typed language, it has to provide an appropriate type for every Function which comes with a different number of arguments. If you define a Function with two arguments, the compiler picks Function2 as the underlying type. Also, from Michael Froh's blog You need to make FunctionN classes for each number of parameters that you want? Yes, but you define the classes once and then you use them forever, or ideally they're already defined in a library (e.g. Functional Java defines classes F, F2, ..., F8, and the Scala standard library defines classes Function1, ..., Function22) So we have a list of function traits (Scala), and a list of interfaces (Functional-java) to enable us to have first class funtions. I am trying to understand exactly why this is the case. I know, in Java for example, when I write a method say, public int add(int a, int b){ return a + b; } That I cannot go ahead and write add(3,4,5); ( error would be something like : method add cannot be applied to give types ) We simply have to define an interface/trait for functions with different parameters, because of static typing?

Read the article

SQL Server Date Comparison Functions

- by HighAltitudeCoder

A few months ago, I found myself working with a repetitive cursor that looped until the data had been manipulated enough times that it was finally correct. The cursor was heavily dependent upon dates, every time requiring the earlier of two (or several) dates in one stored procedure, while requiring the later of two dates in another stored procedure. In short what I needed was a function that would allow me to perform the following evaluation: WHERE MAX(Date1, Date2) < @SomeDate The problem is, the MAX() function in SQL Server does not perform this functionality. So, I set out to put these functions together. They are titled: EarlierOf() and LaterOf(). /********************************************************** EarlierOf.sql **********************************************************/ /********************************************************** Return the later of two DATETIME variables. Parameter 1: DATETIME1 Parameter 2: DATETIME2 Works for a variety of DATETIME or NULL values. Even though comparisons with NULL are actually indeterminate, we know conceptually that NULL is not earlier or later than any other date provided. SYNTAX: SELECT dbo.EarlierOf('1/1/2000','12/1/2009') SELECT dbo.EarlierOf('2009-12-01 00:00:00.000','2009-12-01 00:00:00.521') SELECT dbo.EarlierOf('11/15/2000',NULL) SELECT dbo.EarlierOf(NULL,'1/15/2004') SELECT dbo.EarlierOf(NULL,NULL) **********************************************************/ USE AdventureWorks GO IF EXISTS (SELECT * FROM sysobjects WHERE name = 'EarlierOf' AND xtype = 'FN' ) BEGIN DROP FUNCTION EarlierOf END GO CREATE FUNCTION EarlierOf ( @Date1 DATETIME, @Date2 DATETIME ) RETURNS DATETIME AS BEGIN DECLARE @ReturnDate DATETIME IF (@Date1 IS NULL AND @Date2 IS NULL) BEGIN SET @ReturnDate = NULL GOTO EndOfFunction END ELSE IF (@Date1 IS NULL AND @Date2 IS NOT NULL) BEGIN SET @ReturnDate = @Date2 GOTO EndOfFunction END ELSE IF (@Date1 IS NOT NULL AND @Date2 IS NULL) BEGIN SET @ReturnDate = @Date1 GOTO EndOfFunction END ELSE BEGIN SET @ReturnDate = @Date1 IF @Date2 < @Date1 SET @ReturnDate = @Date2 GOTO EndOfFunction END EndOfFunction: RETURN @ReturnDate END -- End Function GO ---- Set Permissions --GRANT SELECT ON EarlierOf TO UserRole1 --GRANT SELECT ON EarlierOf TO UserRole2 --GO The inverse of this function is only slightly different. /********************************************************** LaterOf.sql **********************************************************/ /********************************************************** Return the later of two DATETIME variables. Parameter 1: DATETIME1 Parameter 2: DATETIME2 Works for a variety of DATETIME or NULL values. Even though comparisons with NULL are actually indeterminate, we know conceptually that NULL is not earlier or later than any other date provided. SYNTAX: SELECT dbo.LaterOf('1/1/2000','12/1/2009') SELECT dbo.LaterOf('2009-12-01 00:00:00.000','2009-12-01 00:00:00.521') SELECT dbo.LaterOf('11/15/2000',NULL) SELECT dbo.LaterOf(NULL,'1/15/2004') SELECT dbo.LaterOf(NULL,NULL) **********************************************************/ USE AdventureWorks GO IF EXISTS (SELECT * FROM sysobjects WHERE name = 'LaterOf' AND xtype = 'FN' ) BEGIN DROP FUNCTION LaterOf END GO CREATE FUNCTION LaterOf ( @Date1 DATETIME, @Date2 DATETIME ) RETURNS DATETIME AS BEGIN DECLARE @ReturnDate DATETIME IF (@Date1 IS NULL AND @Date2 IS NULL) BEGIN SET @ReturnDate = NULL GOTO EndOfFunction END ELSE IF (@Date1 IS NULL AND @Date2 IS NOT NULL) BEGIN SET @ReturnDate = @Date2 GOTO EndOfFunction END ELSE IF (@Date1 IS NOT NULL AND @Date2 IS NULL) BEGIN SET @ReturnDate = @Date1 GOTO EndOfFunction END ELSE BEGIN SET @ReturnDate = @Date1 IF @Date2 > @Date1 SET @ReturnDate = @Date2 GOTO EndOfFunction END EndOfFunction: RETURN @ReturnDate END -- End Function GO ---- Set Permissions --GRANT SELECT ON LaterOf TO UserRole1 --GRANT SELECT ON LaterOf TO UserRole2 --GO The interesting thing about this function is its simplicity and the built-in NULL handling functionality. Its interesting, because it seems like something should already exist in SQL Server that does this. From a different vantage point, if you create this functionality and it is easy to use (ideally, intuitively self-explanatory), you have made a successful contribution. Interesting is good. Self-explanatory, or intuitive is FAR better. Happy coding! Graeme

Read the article

Dallas First Regionals 2012– For Inspiration and Recognition of Science and Technology

- by T

Wow! That is all I have to say after the last 3 days. Three full fun filled days in a world that fed the geek, sparked the competitor, inspired the humanitarian, encouraged the inventor, and continuously warmed my heart. As part of the Dallas First Regionals, I was awed by incredible students who teach as much as they learn, inventive and truly caring mentors that make mentoring look easy, and completely passionate and dedicated volunteers that bring meaning to giving all that you have and making events fun and safe for all. If you have any interest in innovation, robotics, or highly motivated students, I can’t recommend anything any higher than visiting a First Robotics event. This is my third year with First and I was honored enough to serve the Dallas First Regionals as both a Web Site evaluator and as the East Field Volunteer Coordinator. This was also the first year my daughter volunteered with me. My daughter and I both recognize how different the First program is from other team events. The difference with First is that everyone is a first class citizen. It is a difference we can feel through experiencing and observing interactions between executives, respected engineers, students, and event staff. Even with a veracious competition, you still find a lot of cooperation and we never witnessed any belittling between teams or individuals. First Robotics coined the term “Gracious Professionalism”. It's a way of doing things that encourages high-quality work, emphasizes the value of others, and respects individuals and the community.1 I was introduced to this term as the Volunteer Coordinator when I was preparing the volunteer instructional speech. Through the next few days, I discovered it is truly core to everything that First does. One of the ways First accomplishes Gracious Professionalism is by utilizing another term they came up with which is “CoopertitionTM”. At FIRST, CoopertitionTM is displaying unqualified kindness and respect in the face of fierce competition.1 One of the things I never liked about sports was the need to “destroy” the other team. First has really found a way to integrate CoopertitionTM into the rules so teams can be competitive and part of that competition rewards cooperation. Oh and did I mention it has ROBOTS!!! This year it had basket ball playing Kinect connected, remote controlled, robots! There are not words for how exciting these games are. You HAVE to check out this years game, Rebound Rumble, on youtube or you can view live action on Dallas First Video (as of this posting, the recording haven’t posted yet but should be there soon). There are also some images below. Whatever it is, these students get it and exemplify it and these mentors ooze with it. I am glad that First supports these events so we can all learn and be inspired by these exceptional students and mentors. I know that no matter how much I give, it will never compare to what I gain volunteering at First. Even if you don’t have time to volunteer, you owe it to yourself to go check out one of these events. See what the future holds, be inspired, be encouraged, take some knowledge, leave some knowledge and most of all, have FUN. That is what First is all about and thanks to First, I get it. First Dallas Regionals 2012 VIEW SLIDE SHOW DOWNLOAD ALL 1. USFirst http://www.usfirst.org/aboutus/gracious-professionalism

Read the article

F#: Advantages of converting top-level functions to member methods?

- by J Cooper

Earlier I requested some feedback on my first F# project. Before closing the question because the scope was too large, someone was kind enough to look it over and leave some feedback. One of the things they mentioned was pointing out that I had a number of regular functions that could be converted to be methods on my datatypes. Dutifully I went through changing things like let getDecisions hand = let (/=/) card1 card2 = matchValue card1 = matchValue card2 let canSplit() = let isPair() = match hand.Cards with | card1 :: card2 :: [] when card1 /=/ card2 -> true | _ -> false not (hasState Splitting hand) && isPair() let decisions = [Hit; Stand] let split = if canSplit() then [Split] else [] let doubleDown = if hasState Initial hand then [DoubleDown] else [] decisions @ split @ doubleDown to this: type Hand // ...stuff... member hand.GetDecisions = let (/=/) (c1 : Card) (c2 : Card) = c1.MatchValue = c2.MatchValue let canSplit() = let isPair() = match hand.Cards with | card1 :: card2 :: [] when card1 /=/ card2 -> true | _ -> false not (hand.HasState Splitting) && isPair() let decisions = [Hit; Stand] let split = if canSplit() then [Split] else [] let doubleDown = if hand.HasState Initial then [DoubleDown] else [] decisions @ split @ doubleDown Now, I don't doubt I'm an idiot, but other than (I'm guessing) making C# interop easier, what did that gain me? Specifically, I found a couple *dis*advantages, not counting the extra work of conversion (which I won't count, since I could have done it this way in the first place, I suppose, although that would have made using F# Interactive more of a pain). For one thing, I'm now no longer able to work with function "pipelining" easily. I had to go and change some |> chained |> calls to (some |> chained).Calls etc. Also, it seemed to make my type system dumber--whereas with my original version, my program needed no type annotations, after converting largely to member methods, I got a bunch of errors about lookups being indeterminate at that point, and I had to go and add type annotations (an example of this is in the (/=/) above). I hope I haven't come off too dubious, as I appreciate the advice I received, and writing idiomatic code is important to me. I'm just curious why the idiom is the way it is :) Thanks!

Read the article

SQL SERVER – Number-Crunching with SQL Server – Exceed the Functionality of Excel

- by Pinal Dave

Imagine this. Your users have developed an Excel spreadsheet that extracts data from your SQL Server database, manipulates that data through the use of Excel formulas and, possibly, some VBA code which is then used to calculate P&L, hedging requirements or even risk numbers. Management comes to you and tells you that they need to get rid of the spreadsheet and that the results of the spreadsheet calculations need to be persisted on the database. SQL Server has a very small set of functions for analyzing data. Excel has hundreds of functions for analyzing data, with many of them focused on specific financial and statistical calculations. Is it even remotely possible that you can use SQL Server to replace the complex calculations being done in a spreadsheet? Westclintech has developed a library of functions that match or exceed the functionality of Excel’s functions and contains many functions that are not available in EXCEL. Their XLeratorDB library of functions contains over 700 functions that can be incorporated into T-SQL statements. XLeratorDB takes advantage of the SQL CLR architecture introduced in SQL Server 2005. SQL CLR permits managed code to be compiled into the database and run alongside built-in SQL Server functions like COUNT or SUM. The Westclintech developers have taken advantage of this architecture to bring robust analytical functions to the database. In our hypothetical spreadsheet, let’s assume that our users are using the YIELD function and that the data are extracted from a table in our database called BONDS. Here’s what the spreadsheet might look like. We go to column G and see that it contains the following formula. Obviously, SQL Server does not offer a native YIELD function. However, with XLeratorDB we can replicate this calculation in SQL Server with the following statement: SELECT *, wct.YIELD(CAST(GETDATE() AS date),Maturity,Rate,Price,100,Frequency,Basis) AS YIELD FROM BONDS This produces the following result. This illustrates one of the best features about XLeratorDB; it is so easy to use. Since I knew that the spreadsheet was using the YIELD function I could use the same function with the same calling structure to do the calculation in SQL Server. I didn’t need to know anything at all about the mechanics of calculating the yield on a bond. It was pretty close to cut and paste. In fact, that’s one way to construct the SQL. Just copy the function call from the cell in the spreadsheet and paste it into SMS and change the cell references to column names. I built the SQL for this query by starting with this. SELECT * ,YIELD(TODAY(),B2,C2,D2,100,E2,F2) FROM BONDS I then changed the cell references to column names. SELECT * --,YIELD(TODAY(),B2,C2,D2,100,E2,F2) ,YIELD(TODAY(),Maturity,Rate,Price,100,Frequency,Basis) FROM BONDS Finally, I replicated the TODAY() function using GETDATE() and added the schema name to the function name. SELECT * --,YIELD(TODAY(),B2,C2,D2,100,E2,F2) --,YIELD(TODAY(),Maturity,Rate,Price,100,Frequency,Basis) ,wct.YIELD(GETDATE(),Maturity,Rate,Price,100,Frequency,Basis) FROM BONDS Then I am able to execute the statement returning the results seen above. The XLeratorDB libraries are heavy on financial, statistical, and mathematical functions. Where there is an analog to an Excel function, the XLeratorDB function uses the same naming conventions and calling structure as the Excel function, but there are also hundreds of additional functions for SQL Server that are not found in Excel. You can find the functions by opening Object Explorer in SQL Server Management Studio (SSMS) and expanding the Programmability folder under the database where the functions have been installed. The Functions folder expands to show 3 sub-folders: Table-valued Functions; Scalar-valued functions, Aggregate Functions, and System Functions. You can expand any of the first three folders to see the XLeratorDB functions. Since the wct.YIELD function is a scalar function, we will open the Scalar-valued Functions folder, scroll down to the wct.YIELD function and and click the plus sign (+) to display the input parameters. The functions are also Intellisense-enabled, with the input parameters displayed directly in the query tab. The Westclintech website contains documentation for all the functions including examples that can be copied directly into a query window and executed. There are also more one hundred articles on the site which go into more detail about how some of the functions work and demonstrate some of the extensive business processes that can be done in SQL Server using XLeratorDB functions and some T-SQL. XLeratorDB is organized into libraries: finance, statistics; math; strings; engineering; and financial options. There is also a windowing library for SQL Server 2005, 2008, and 2012 which provides functions for calculating things like running and moving averages (which were introduced in SQL Server 2012), FIFO inventory calculations, financial ratios and more, without having to use triangular joins. To get started you can download the XLeratorDB 15-day free trial from the Westclintech web site. It is a fully-functioning, unrestricted version of the software. If you need more than 15 days to evaluate the software, you can simply download another 15-day free trial. XLeratorDB is an easy and cost-effective way to start adding sophisticated data analysis to your SQL Server database without having to know anything more than T-SQL. Get XLeratorDB Today and Now! Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Excel

Read the article

A new mission statement for my school's algorithms class

- by Eric Fode

The teacher at Eastern Washington University that is now teaching the algorithms course is new to eastern and as a result the course has changed drastically mostly in the right direction. That being said I feel that the class could use a more specific, and industry oriented (since that is where most students will go, though suggestions for an academia oriented class are also welcome) direction, having only worked in industry for 2 years I would like the community's (a wider and much more collectively experienced and in the end plausibly more credible) opinion on the quality of this as a statement for the purpose an algorithms class, and if I am completely off target your suggestion for the purpose of a required Jr. level Algorithms class that is standalone (so no other classes focusing specifically on algorithms are required). The statement is as follows: The purpose of the algorithms class is to do three things: Primarily, to teach how to learn, do basic analysis, and implement a given algorithm found outside of the class. Secondly, to teach the student how to model a problem in their mind so that they can find a an existing algorithm or have a direction to start the development of a new algorithm. Third, to overview a variety of algorithms that exist and to deeply understand and analyze one algorithm in each of the basic algorithmic design strategies: Divide and Conquer, Reduce and Conquer, Transform and Conquer, Greedy, Brute Force, Iterative Improvement and Dynamic Programming. The Question in short is: do you agree with this statement of the purpose of an algorithms course, so that it would be useful in the real world, if not what would you suggest?

Read the article

Calling a .NET C# class from XSLT

- by HanSolo

If you've ever worked with XSLT, you'd know that it's pretty limited when it comes to its programming capabilities. Try writing a for loop in XSLT and you'd know what I mean. XSLT is not designed to be a programming language so you should never put too much programming logic in your XSLT. That code can be a pain to write and maintain and so it should be avoided at all costs. Keep your xslt simple and put any complex logic that your xslt transformation requires in a class. Here is how you can create a helper class and call that from your xslt. For example, this is my helper class: public class XsltHelper { public string GetStringHash(string originalString) { return originalString.GetHashCode().ToString(); } } And this is my xslt file(notice the namespace declaration that references the helper class): <?xml version="1.0" encoding="UTF-8" ?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns:ext="http://MyNamespace"> <xsl:output method="text" indent="yes" omit-xml-declaration="yes"/> <xsl:template match="/">The hash code of "<xsl:value-of select="stringList/string1" />" is "<xsl:value-of select="ext:GetStringHash(stringList/string1)" />". </xsl:template> </xsl:stylesheet> Here is how you can include the helper class as part of the transformation: string xml = "<stringList><string1>test</string1></stringList>"; XmlDocument xmlDocument = new XmlDocument(); xmlDocument.LoadXml(xml); XslCompiledTransform xslCompiledTransform = new XslCompiledTransform(); xslCompiledTransform.Load("XSLTFile1.xslt"); XsltArgumentList xsltArgs = new XsltArgumentList(); xsltArgs.AddExtensionObject("http://MyNamespace", Activator.CreateInstance(typeof(XsltHelper))); using (FileStream fileStream = new FileStream("TransformResults.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite)) { // transform the xml and output to the output file ... xslCompiledTransform.Transform(xmlDocument, xsltArgs, fileStream); }

Read the article

Is writing recursive functions hard for you?

- by null

I'm taking a computer science course now. I feel it is so hard compared to my polytechnic IT course. I can't understand recursive methods well. How do you manage to get your brain to understand it? When the recursive method returns back, my brain can not trace it nicely. Is there a better way to understand recursion? How do you start learning it? Is it normal that feel that it is very hard at then beginning? Look at the example, I'm very surprised how can I write this if it appears in exam. public class Permute { public static void main(String[] args) { new Permute().printPerms(3); } boolean[] used; int max; public void printPerms(int size) { used = new boolean[size]; max = size; for (int i = 0; i < size; i++) { used[i] = false; } perms(size, ""); } public void perms(int remaining, String res) { if (remaining == 0) { System.out.println(res); } else { for (int i = 0; i < max; i++) { if (!(used[i])) { used[i] = true; perms(remaining - 1, res + " " + i); used[i] = false; } } } } }

Read the article

Updating entities in response to collisions - should this be in the collision-detection class or in the entity-updater class?

- by Prog

In a game I'm working on, there's a class responsible for collision detection. It's method detectCollisions(List<Entity> entities) is called from the main gameloop. The code to update the entities (i.e. where the entities 'act': update their positions, invoke AI, etc) is in a different class, in the method updateEntities(List<Entity> entities). Also called from the gameloop, after the collision detection. When there's a collision between two entities, usually something needs to be done. For example, zero the velocity of both entities in the collision, or kill one of the entities. It would be easy to have this code in the CollisionDetector class. E.g. in psuedocode: for(Entity entityA in entities){ for(Entity entityB in entities){ if(collision(entityA, entityB)){ if(entityA instanceof Robot && entityB instanceof Robot){ entityA.setVelocity(0,0); entityB.setVelocity(0,0); } if(entityA instanceof Missile || entityB instanceof Missile){ entityA.die(); entityB.die(); } } } } However, I'm not sure if updating the state of entities in response to collision should be the job of CollisionDetector. Maybe it should be the job of EntityUpdater, which runs after the collision detection in the gameloop. Is it okay to have the code responding to collisions in the collision detection system? Or should the collision detection class only detect collisions, report them to some other class and have that class affect the state of the entities?

Read the article

Class Decorators, Inheritence, super(), and maximum recursion

- by jamstooks

I'm trying to figure out how to use decorators on subclasses that use super(). Since my class decorator creates another subclass a decorated class seems to prevent the use of super() when it changes the className passed to super(className, self). Below is an example: def class_decorator(cls): class _DecoratedClass(cls): def __init__(self): return super(_DecoratedClass, self).__init__() return _DecoratedClass class BaseClass(object): def __init__(self): print "class: %s" % self.__class__.__name__ def print_class(self): print "class: %s" % self.__class__.__name__ bc = BaseClass().print_class() class SubClass(BaseClass): def print_class(self): super(SubClass, self).print_class() sc = SubClass().print_class() @class_decorator class SubClassAgain(BaseClass): def print_class(self): super(SubClassAgain, self).print_class() sca = SubClassAgain() # sca.print_class() # Uncomment for maximum recursion The output should be: class: BaseClass class: BaseClass class: SubClass class: SubClass class: _DecoratedClass Traceback (most recent call last): File "class_decorator_super.py", line 34, in <module> sca.print_class() File "class_decorator_super.py", line 31, in print_class super(SubClassAgain, self).print_class() ... ... RuntimeError: maximum recursion depth exceeded while calling a Python object Does anyone know of a way to not break a subclass that uses super() when using a decorator? Ideally I'd like to reuse a class from time to time and simply decorate it w/out breaking it.

Read the article

Adding a class to the $tag surrounding a <label> in a Zend_Form with the Label decorator

- by Roderik

I'm trying to get the following html out of Zend_Form <div class="group wat-cf"> <div class="left"> <label class="label right">Username</label> </div> <div class="right"> <input type="text" class="text_field"> </div> </div> Using the following code: $username->setAttrib("class", "text_field") ->setDecorators(array( 'ViewHelper', 'Description', 'Errors', array(array('data'=>'HtmlTag'), array('tag' => 'div', 'class' => 'right')), array('Label', array('tag' => 'div', 'class' => 'label right')), array(array('row'=>'HtmlTag'),array('tag'=>'div', 'class' => 'group wat-cf')) )); I can get the next fragment <div class="group wat-cf"> <div id="username-label"> <label for="username" class="label right required">Username:</label> </div> <div class="right"> <input type="text" name="username" id="username" value="" class="text_field"> </div> </div> so apart from some extra id's and required classes i don't mind, i need to get a class "left" on div id="username-label" Now adding class to the Label line, gets the class added on the element. I also don't see and option to do this in the Label decorator code itself. So i need a custom Label decorator, or is there some other way i'm missing?

Read the article

templated method on T inside a templated class on TT : Is that possible/correct.

- by paercebal

I have a class MyClass which is templated on typename T. But inside, I want a method which is templated on another type TT (which is unrelated to T). After reading/tinkering, I found the following notation: template <typename T> class MyClass { public : template<typename TT> void MyMethod(const TT & param) ; } ; For stylistic reasons (I like to have my templated class declaration in one header file, and the method definitions in another header file), I won't define the method inside the class declaration. So, I have to write it as: template <typename T> // this is the type of the class template <typename TT> // this is the type of the method void MyClass<T>::MyMethod(const TT & param) { // etc. } I knew I had to "declare" the typenames used in the method, but didn't know how exactly, and found through trials and errors. The code above compiles on Visual C++ 2008, but: Is this the correct way to have a method templated on TT inside a class templated on T? As a bonus: Are there hidden problems/surprises/constraints behind this kind of code? (I guess the specializations can be quite amusing to write)

Read the article

Does query plan optimizer works well with joined/filtered table-valued functions?

- by smoothdeveloper

In SQLSERVER 2005, I'm using table-valued function as a convenient way to perform arbitrary aggregation on subset data from large table (passing date range or such parameters). I'm using theses inside larger queries as joined computations and I'm wondering if the query plan optimizer work well with them in every condition or if I'm better to unnest such computation in my larger queries. Does query plan optimizer unnest table-valued functions if it make sense? If it doesn't, what do you recommend to avoid code duplication that would occur by manually unnesting them? If it does, how do you identify that from the execution plan? code sample: create table dbo.customers ( [key] uniqueidentifier , constraint pk_dbo_customers primary key ([key]) ) go /* assume large amount of data */ create table dbo.point_of_sales ( [key] uniqueidentifier , customer_key uniqueidentifier , constraint pk_dbo_point_of_sales primary key ([key]) ) go create table dbo.product_ranges ( [key] uniqueidentifier , constraint pk_dbo_product_ranges primary key ([key]) ) go create table dbo.products ( [key] uniqueidentifier , product_range_key uniqueidentifier , release_date datetime , constraint pk_dbo_products primary key ([key]) , constraint fk_dbo_products_product_range_key foreign key (product_range_key) references dbo.product_ranges ([key]) ) go . /* assume large amount of data */ create table dbo.sales_history ( [key] uniqueidentifier , product_key uniqueidentifier , point_of_sale_key uniqueidentifier , accounting_date datetime , amount money , quantity int , constraint pk_dbo_sales_history primary key ([key]) , constraint fk_dbo_sales_history_product_key foreign key (product_key) references dbo.products ([key]) , constraint fk_dbo_sales_history_point_of_sale_key foreign key (point_of_sale_key) references dbo.point_of_sales ([key]) ) go create function dbo.f_sales_history_..snip.._date_range ( @accountingdatelowerbound datetime, @accountingdateupperbound datetime ) returns table as return ( select pos.customer_key , sh.product_key , sum(sh.amount) amount , sum(sh.quantity) quantity from dbo.point_of_sales pos inner join dbo.sales_history sh on sh.point_of_sale_key = pos.[key] where sh.accounting_date between @accountingdatelowerbound and @accountingdateupperbound group by pos.customer_key , sh.product_key ) go -- TODO: insert some data -- this is a table containing a selection of product ranges declare @selectedproductranges table([key] uniqueidentifier) -- this is a table containing a selection of customers declare @selectedcustomers table([key] uniqueidentifier) declare @low datetime , @up datetime -- TODO: set top query parameters . select saleshistory.customer_key , saleshistory.product_key , saleshistory.amount , saleshistory.quantity from dbo.products p inner join @selectedproductranges productrangeselection on p.product_range_key = productrangeselection.[key] inner join @selectedcustomers customerselection on 1 = 1 inner join dbo.f_sales_history_..snip.._date_range(@low, @up) saleshistory on saleshistory.product_key = p.[key] and saleshistory.customer_key = customerselection.[key] I hope the sample makes sense. Much thanks for your help!

Read the article

Can a grails controller extend from a base class? How to make it so grails doesn't blow up?

- by egervari

I wrote a base class to help build my controllers more quickly and to remove duplication. It provides some helper methods, default actions and some meta programming to make these things easier to build. One of those methods in the base class is like this: def dynamicList(Class clazz) { def model = new LinkedHashMap() model[getMapString(clazz) + "s"] = list(clazz) model[getMapString(clazz) + "sTotal"] = count(clazz) model } The action that calls it, also in the base class, is this: def list = { dynamicList(clazz) } Unfortunately, when I go to list action in the controller subclass that inherits the base class when my application is deployed, I get this exception: groovy.lang.MissingMethodException: No signature of method: groovy.lang.MissingMethodException.dynamicList() is applicable for argument types: (java.lang.Class) values: [class project .user.User] at project.user.UserController$_closure1.doCall(UserController.groovy:18) at project.user.UserController$_closure1.doCall(UserController.groovy) at java.lang.Thread.run(Thread.java:619) How can I hit grails over the head and just tell it do what I want it to do? My controller unit tests run just fine, so grails' run-time is totally at fault :/ Ken

Read the article

How to deal with class composition when components cannot be accessed from the outside?

- by Chathuranga

For example if I say I have three classes A, B, and C where B and C have a composition relation ship with A. That means the life of B and C is handled by A, and also B and C cannot access directly from the outside. For some reason my DataService class needs to return objects of B and C as It cant return a object of A as B and C cannot be initialized at the same time. (to be able to initializeC you have to initializeB first). So that I'm returning DataTables from DataService and then inside the class A those data tables are converted to B / C objects. If B and C objects cannot be initialized at the same time is it valid to say that B and C have a composition relationship with A? If its composition is it must to generate A with B and C inside? What is the proper way to handle this sort of a problem? EDIT: Following code explains the way I'm doing it now with DataTables. Example: class A { private List<B> B; private List <C> C; public A() { B= new List<B>(); C= new List<C>(); } public List<B> GetB( DataTable dt) { // Create a B list from dt return B; } } class Presenter { private void Show B() { _View.DataGrid = A.GetB(DataService.GetAListOfB()); } } The actual scenario is I have a class called WageInfo and classes Earning and Deduction having a composition relationship in the design. But for you to generate Deductions first you should Generate earnings and should be saved in a table. Then only you can generate deductions for the earnings to calculate balance wages. Also note that these contained classes have a one to many relationship with the containing class WageInfo. So actually WageInfo has a List<Earnings> and List<Deduction> My initial question was, is it ok if my DataService class returns Deductions / Earnings objects (actually lists) not a WageInfo? Still not clear?

Search Results

Search found 88144 results on 3526 pages for 'first class functions'.

Page 50/3526 | < Previous Page | 46 47 48 49 50 51 52 53 54 55 56 57 | Next Page >

- by m0j1

- by Keand64

- by Hooman

- by user559601

- by thkang

- by AukI

- by Electric Coffee

- by Mark Tomlin

- by EOL

- by Heatsink

- by Luke Murphy

- by HighAltitudeCoder

- by T

- by J Cooper

- by Pinal Dave

- by Eric Fode

- by HanSolo

- by null

- by Prog

- by jamstooks

- by Roderik

- by paercebal

- by smoothdeveloper

- by egervari

- by Chathuranga

< Previous Page | 46 47 48 49 50 51 52 53 54 55 56 57 | Next Page >