Search Results

Search found 11672 results on 467 pages for 'formal methods'.

Page 339/467 | < Previous Page | 335 336 337 338 339 340 341 342 343 344 345 346  | Next Page >

  • Why is my primitive xna square not drawn/shown?

    - by Mech0z
    I have made this class to draw a rectangle, but I cant get it to be drawn, I have no issues displaying a 3d model created in 3dmax, but shown these primitives seems much harder I use this to create it board = new Board(Vector3.Zero, 1000, 1000, Color.Yellow); And here is the implementation using System; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Ink; using System.Windows.Input; using System.Windows.Shapes; using Quadro.Models; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; namespace Quadro { public class Board : IGraphicObject { //Private Fields private Vector3 modelPosition; private BasicEffect effect; private VertexPositionColor[] vertices; private Matrix rotationMatrix; private GraphicsDevice graphicsDevice; private Matrix cameraProjection; //Constructor public Board(Vector3 position, float length, float width, Color color) { var _color = color; vertices = new VertexPositionColor[6]; vertices[0].Position = new Vector3(position.X, position.Y, position.Z); vertices[1].Position = new Vector3(position.X, position.Y + width, position.Z); vertices[2].Position = new Vector3(position.X + length, position.Y, position.Z); vertices[3].Position = new Vector3(position.X + length, position.Y, position.Z); vertices[4].Position = new Vector3(position.X, position.Y + width, position.Z); vertices[5].Position = new Vector3(position.X + length, position.Y + width, position.Z); for(int i = 0; i < vertices.Length; i++) { vertices[i].Color = color; } initFields(); } private void initFields() { graphicsDevice = SharedGraphicsDeviceManager.Current.GraphicsDevice; effect = new BasicEffect(graphicsDevice); modelPosition = Vector3.Zero; float screenWidth = (float)graphicsDevice.Viewport.Width; float screenHeight = (float)graphicsDevice.Viewport.Height; float aspectRatio = screenWidth / screenHeight; this.cameraProjection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), aspectRatio, 1.0f, 10000.0f); this.rotationMatrix = Matrix.Identity; } //Public Methods public void Update(GameTimerEventArgs e) { } public void Draw(Vector3 cameraPosition, GameTimerEventArgs e) { Matrix cameraView = Matrix.CreateLookAt(cameraPosition, Vector3.Zero, Vector3.Up); foreach (EffectPass pass in effect.CurrentTechnique.Passes) { pass.Apply(); effect.World = rotationMatrix * Matrix.CreateTranslation(modelPosition); effect.View = cameraView; effect.Projection = cameraProjection; graphicsDevice.DrawUserPrimitives(PrimitiveType.TriangleList, vertices, 0, 2, VertexPositionColor.VertexDeclaration); } } public void Rotate(Matrix rotationMatrix) { this.rotationMatrix = rotationMatrix; } public void Move(Vector3 moveVector) { this.modelPosition += moveVector; } } }

    Read the article

  • Brain Teaser: How Did I Do This (Part 1: The Solution)

    - by Geertjan
    In Part 1: The Challenge, published this time last week, I introduced a "brain teaser". The brain teaser asks you to figure out how to allow images and other files to be meaningfully dropped onto a NetBeans Platform application, i.e., on the drop something useful should happen with the dropped file: if the file is an image, the image should open in the IDE; if the file is a PDF document, the PDF viewer should open externally; if the file is a text file, it should open as a text in the IDE, etc. Solution. And here is the solution: http://bits.netbeans.org/dev/javadoc/org-openide-windows/org/openide/windows/ExternalDropHandler.html When an implementation of the "ExternalDropHandler" class is available in the global Lookup, and an object is being dragged over some part of the main window, the window system may call the methods of this class to decide whether it can accept or reject the drag operation. And when the object is actually dropped, this class will be asked to handle the drop. OK, so go ahead and implement the above class and put it into the Lookup. Or... guess what? The NetBeans Platform has a default implementation of the above class, appropriately named "DefaultExternalDropHandler". Not only is this useful to learn about how to implement the ExternalDropHandler class (i.e., by reading the source here): you can simply include the module that contains this class in your own NetBeans Platform application and then your application will be able to receive external drag/drop events and do something meaningful with them thanks to the DefaultExternalDropHandler. Do this: Open your NetBeans Platform application in NetBeans IDE. Right-click the application in the Projects window and choose Properties. In the Libraries tab, expand the "ide" cluster, and select "User Utilities". (That's where "DefaultExternalDropHandler.java" is found and registered in the Lookup.) Now click the "Resolve" button, if it appears, because some additional related modules need to now be included, if they haven't been included yet. Again in the "ide" cluster in the Libraries tab, select "Image". That's the Image Editor. Click OK. Run the application. Drag an image or some other type of file into your application, from outside the application, and you'll see the application tries to handle the drop. If the file being dragged is an image, it will open in the Image Editor, which you included in the previous step of these instructions. Hurray, you're done. Without any programming at all, you've added a cool new feature to your application.

    Read the article

  • Is my JavaScript/jQuery methodology good? [migrated]

    - by absentx
    I am seeking critique on what has become my normal methodology of writing JavaScript code. I have become heavily reliant on the jQuery library, but I think this has helped me learn the native language better also. Anyway, please critique the following style of JavaScript coding... Buried are a lot of questions of scope; if you could point out the strengths and weaknesses of this style I would appreciate it. var critique ={ start: function(){ globalness = 'GLOBAL-GLOBAL'; //Available to all critique's methods var notglobalness = 'LOCAL-LOCAL'; // Only available to critiques start method //Am I using the "method" teminology properly here?? $('#stuff').on('click','a.closer-target',function(){ $target = $(this); if($target.hasClass('active')){ $target.removeClass('active'); } else{ $target.addClass('active'); critique.madness($target); } }) console.log(notglobalness+': at least I am useful at home'); console.log('note here that: '+notglobalness+' is no longer available after this point, lets continue on:'); critique.madness(notglobalness); }, madness: function($e){ //Do a bunch of awesomeness with $e, //but continue to keep it seperate because you think its best to keep things isolated. //Send to the next function when complete here console.log('Here is globalness, which is still available from the start method of critique!! ' + globalness); console.log('Let us see if the globalness carries on to a new var object!!'); console.log('The locally isolated variable of NOTGLOBALNESS is available here, because it was passed to this method. Let us show it:'+$e); carryOn.start(); } } //end critique var carryOn={ start: function(){ console.log('any chance critique.globalness will work here??? lets see: ' +globalness); console.log('it absolutely does'); } } $(document).ready(critique.start); (I always struggle with which of the Stack Exchange sites is best to post "questions of theory" like this, but I think Programmers is the best, if not, as usual a mod will move it, etc...)

    Read the article

  • Determining whether a visitor reached two different pages in one visit

    - by Shaun
    I have a funnel that I would like to track. Tracking this funnel won't work with the default "goal funnel" tracking in Google due to the fact that I am mixing events and pageviews. As such, I've created a series of reports: Visits to demo pages - An inclusion filter on "Page". Triggers an Event on these pages - An inclusion filter on "Page" and "Event Category". Does not bounce - An inclusion filter on "Page" and an exclusion filter on "Exit Page" for these same pages. Reach our storefront - ?? Purchase something - An inclusion filter on "Page" and a report that shows "Transactions". At a basic level, I need to track users who reached demo pages, then reached any page on our store. Intuitively, I created a segment, used two inclusive "Page" filters (one for the demo pages and one for any page in our store), and combined them with an "AND" operator. I thought this was working until I tried to do the same thing in a dashboard widget and on a custom report. When I tried the same thing in those areas, I got zero results. I figured this might be because widgets and custom report filters function differently from segment filters (the options are different for all of them), so I tried applying my "demo page && store page" segment to a report that gave me a general page list. All I saw was a list of the specific pages. I tried simplifying things by creating a custom report that showed all visits to store pages, then applied a segment that filtered for users who visited demo pages. This got me the same numbers as my "demo page && store page" segment, but showed a list of demo pages. This has led me to believe that the "demo page && store page segment" approach and the "demo segment && store report" functionally behave the same. However, this experience has left me questioning whether they're giving me what I want. Are these methods showing me all users who reached both sets of pages? Is there a better/easier/more standard way of doing this aside from looking at visitor flow reports? I'm trying to avoid a combination of custom variables/events and using the horizontal funnel approach since it would consume a large number of our limited goals and seems more complicated than is necessary for tracking this funnel.

    Read the article

  • Developer career feeling like going back in time every new job [closed]

    - by komediant
    Is there a good category for this question? My background is bachelor in ICT and for a hobby I am programming already since I was around twelve I think. Started with QBasic, Pascal, C, Java et cetera. Currently I am working for about eight/nine years. Half academics/medical and half company world. A few years ago I started with frameworks and I began with Grails (underlying Spring/Hibernate), which was a heavenly job, very productive and no hassle. My previous job I developed in pure Spring/Hibernate Java, which was a bit more writing annotations and XML and no conventions like Grails. But still, I did like Spring/Hibernate a lot and the professional setup with a developmentstreet, versioning, Jenkins/Sonar, log4j and a good IDE like IntellIJ. It felt quite 'clear' and organised, although I knew Grails which felt a bit more productive. But...at my current job almost half the code is pure servlet, hard coded JDBC (connections handled by yourself), scriptlets in all JSP pages, no service layer, no versioning, no Maven, HTML in DAO-layer, JAR-hell, no hot swap deployment locally, every change you have to deploy and hope it works fine on the server. All local development needs ugly scriptlet tags to check which environment it is running. Et cetera. Now and then developers work over in the evening - I don't - and still lots of issues are not solved and new projects are waiting. I hear the developers complaining, but somehow they feel like what they have now is "advanced" or they are in a sort of comfore zone. The lead developer seems open for new things, but half of the times he says he can implement MVC-framework features himself instead of using what is already out there. So in short, I currently feel like I miss all the modern framework techniques and that the company is going so slow forward. I just work here for two months now. What I do now is also code some partially ugly stuff, but it goes in completely into my nature and I feel uncomfortable with it. Coding something takes long(er) than estimated and my manager complains about why it takes so long and I feel ashamed for myself needing so much time. Where I was used to just writing a query I now build up whole try catch methods. My manager knows my complaints and the developers do so too. There will come a meeting to line out plans for 2013 on technology and the issues I and the company are facing. I am not looking for another job yet, it's close to wehre I live and the economy is fragile. Does anyone else have had this kind of career, like feeling going backwards witch technology? And how did you cope with it?

    Read the article

  • Object Oriented Design of a Small Java Game

    - by user2733436
    This is the problem i am dealing with. I have to make a simple game of NIM. I am learning java using a book so far i have only coded programs that deal with 2 classes. This program would have about 4 classes i guess including the main class. My problem is i am having a difficult time designing classes how they will interact with each other. I really want to think and use a object oriented approach. So the first thing i did was design the Pile CLASS as it seemed the easiest and made the most sense to me in terms of what methods go in it. Here is what i have got down for the Pile Class so far. package Nim; import java.util.Random; public class Pile { private int initialSize; public Pile(){ } Random rand = new Random(); public void setPile(){ initialSize = (rand.nextInt(100-10)+10); } public void reducePile(int x){ initialSize = initialSize - x; } public int getPile(){ return initialSize; } public boolean hasStick(){ if(initialSize>0){ return true; } else { return false; } } } Now i need help in designing the Player Class. By that i mean i am not asking for anyone to write code for me as that defeats the purpose of learning i was just wondering how would i design the player class and what would go on it. My guess is that the player class would contain method for choosing move for computer and also receiving the move human user makes. Lastly i am guessing in the Game class i am guessing the turns would be handeled. I am really lost right now so i was wondering if someone can help me think through this problem it would be great. Starting with the player class would be appreciated. I know there are some solutions for this problem online but i refuse to look at because i want to develop my own approach to such problems and i am confident if i can get through this problem i can solve other problems. I apologize if this question is a bit poor but in specific i need help in designing the Player class.

    Read the article

  • Is this a pattern? Should it be?

    - by Arkadiy
    The following is more of a statement than a question - it describes something that may be a pattern. The question is: is this a known pattern? Or, if it's not, should it be? I've had a situation where I had to iterate over two dissimilar multi-layer data structures and copy information from one to the other. Depending on particular use case, I had around eight different kinds of layers, combined in about eight different combinations: A-B-C B-C A-C D-E A-D-E and so on After a few unsuccessful attempts to factor out the repetition of per-layer iteration code, I realized that the key difficulty in this refactoring was the fact that the bottom level needed access to data gathered at higher levels. To explicitly accommodate this requirement, I introduced IterationContext class with a number of get() and set() methods for accumulating the necessary information. In the end, I had the following class structure: class Iterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const = 0; }; class RecursingIterator : public Iterator { RecursingIterator(const Iterator &below); }; class IterateOverA : public RecursingIterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // Iterate over members in dataStructure1 // locate corresponding item in dataStructure2 (passed via context) // and set it in the context // invoke the sub-iterator }; class IterateOverB : public RecursingIterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // iterate over members dataStructure2 (form context) // set dataStructure2's item in the context // locate corresponding item in dataStructure2 (passed via context) // invoke the sub-iterator }; void main() { class FinalCopy : public Iterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // copy data from structure 1 to structure 2 in the context, // using some data from higher levels as needed } } IterationContext ctx(dateStructure2); IterateOverA(IterateOverB(FinalCopy())).iterate(dataStructure1, ctx); } It so happens that dataStructure1 is a uniform data structure, similar to XML DOM in that respect, while dataStructure2 is a legacy data structure made of various structs and arrays. This allows me to pass dataStructure1 outside of the context for convenience. In general, either side of the iteration or both sides may be passed via context, as convenient. The key situation points are: complicated code that needs to be invoked in "layers", with multiple combinations of layer types possible at the bottom layer, the information from top layers needs to be visible. The key implementation points are: use of context class to access the data from all levels of iteration complicated iteration code encapsulated in implementation of pure virtual function two interfaces - one aware of underlying iterator, one not aware of it. use of const & to simplify the usage syntax.

    Read the article

  • is a factory pattern to prevent multuple instances for same object (instance that is Equal) good design?

    - by dsollen
    I have a number of objects storing state. There are essentially two types of fields. The ones that uniquly define what the object is (what node, what edge etc), and the oens that store state describing how these things are connected (this node is connected to these edges, this edge is part of these paths) etc. My model is updating the state variables using package methdos, so these objects all act as immutable to anyone not in Model scope. All Objects extend one base type. I've toyed with the idea of a Factory approch which accepts a Builder object and construct the applicable object. However, if an instance of the object already exists (ie would return true if I created the object defined by the builder and passed it to the equal method for the existing instance) the factory returns the current object instead of creating a new instance. Because the Equal method would only compare what uniquly defines the type of object (this is node A nto node B) but won't check the dynamic state stuff (node A is currently connected to nodes C and E) this would be a way of ensuring anyone that wants my Node A automatically knows it's state connections. More importantly it would prevent aliasing nightmares of someone trying to pass an instance of node A with different state then the node A in my model has. I've never heard of this pattern before, and it's a bit odd. I would have to do some overiding of serlization methods to make it work (ensure when I read in a serilized object I add it to my facotry list of known instances, and/or return an existing factory in it's place), as well as using a weakHashMap as if it was a weakHashSet to know rather an instance exists without worrying about a quasi-memory leak occuring. I don't know if this is too confusing or prone to it's own obscure bugs. One thing I know is that plugins interface with lowest level hardware. The plugins have to be able to return state taht is different then my memory; to tell my memory when it's own state is inconsistent. I believe this is possible despit their fetching objects that exist in my memory; we allow building of objects without checking their consistency with the model until the addToModel is called anyways; and the existing plugins design was written before all this extra state existed and worked fine without ever being aware of it. Should I just be using some other design to avoid this crazyness? (I have another question to that affect I'm posting).

    Read the article

  • Getting a SecurityToken from a RequestSecurityTokenResponse in WIF

    - by Shawn Cicoria
    When you’re working with WIF and WSTrustChannelFactory when you call the Issue operation, you can also request that a RequestSecurityTokenResponse as an out parameter. However, what can you do with that object?  Well, you could keep it around and use it for subsequent calls with the extension method CreateChannelWithIssuedToken – or can you? public static T CreateChannelWithIssuedToken<T>(this ChannelFactory<T> factory, SecurityToken issuedToken);   As you can see from the method signature it takes a SecurityToken – but that’s not present on the RequestSecurityTokenResponse class. However, you can through a little magic get a GenericXmlSecurityToken by means of the following set of extension methods below – just call rstr.GetSecurityTokenFromResponse() – and you’ll get a GenericXmlSecurityToken as a return. public static class TokenHelper { /// <summary> /// Takes a RequestSecurityTokenResponse, pulls out the GenericXmlSecurityToken usable for further WS-Trust calls /// </summary> /// <param name="rstr"></param> /// <returns></returns> public static GenericXmlSecurityToken GetSecurityTokenFromResponse(this RequestSecurityTokenResponse rstr) { var lifeTime = rstr.Lifetime; var appliesTo = rstr.AppliesTo.Uri; var tokenXml = rstr.GetSerializedTokenFromResponse(); var token = GetTokenFromSerializedToken(tokenXml, appliesTo, lifeTime); return token; } /// <summary> /// Provides a token as an XML string. /// </summary> /// <param name="rstr"></param> /// <returns></returns> public static string GetSerializedTokenFromResponse(this RequestSecurityTokenResponse rstr) { var serializedRst = new WSFederationSerializer().GetResponseAsString(rstr, new WSTrustSerializationContext()); return serializedRst; } /// <summary> /// Turns the XML representation of the token back into a GenericXmlSecurityToken. /// </summary> /// <param name="tokenAsXmlString"></param> /// <param name="appliesTo"></param> /// <param name="lifetime"></param> /// <returns></returns> public static GenericXmlSecurityToken GetTokenFromSerializedToken(this string tokenAsXmlString, Uri appliesTo, Lifetime lifetime) { RequestSecurityTokenResponse rstr2 = new WSFederationSerializer().CreateResponse( new SignInResponseMessage(appliesTo, tokenAsXmlString), new WSTrustSerializationContext()); return new GenericXmlSecurityToken( rstr2.RequestedSecurityToken.SecurityTokenXml, new BinarySecretSecurityToken( rstr2.RequestedProofToken.ProtectedKey.GetKeyBytes()), lifetime.Created.HasValue ? lifetime.Created.Value : DateTime.MinValue, lifetime.Expires.HasValue ? lifetime.Expires.Value : DateTime.MaxValue, rstr2.RequestedAttachedReference, rstr2.RequestedUnattachedReference, null); } }

    Read the article

  • Lazy Processing of Streams

    - by Giorgio
    I have the following problem scenario: I have a text file and I have to read it and split it into lines. Some lines might need to be dropped (according to criteria that are not fixed). The lines that are not dropped must be parsed into some predefined records. Records that are not valid must be dropped. Duplicate records may exist and, in such a case, they are consecutive. If duplicate / multiple records exist, only one item should be kept. The remaining records should be grouped according to the value contained in one field; all records belonging to the same group appear one after another (e.g. AAAABBBBCCDEEEFF and so on). The records of each group should be numbered (1, 2, 3, 4, ...). For each group the numbering starts from 1. The records must then be saved somewhere / consumed in the same order as they were produced. I have to implement this in Java or C++. My first idea was to define functions / methods like: One method to get all the lines from the file. One method to filter out the unwanted lines. One method to parse the filtered lines into valid records. One method to remove duplicate records. One method to group records and number them. The problem is that the data I am going to read can be too big and might not fit into main memory: so I cannot just construct all these lists and apply my functions one after the other. On the other hand, I think I do not need to fit all the data in main memory at once because once a record has been consumed all its underlying data (basically the lines of text between the previous record and the current record, and the record itself) can be disposed of. With the little knowledge I have of Haskell I have immediately thought about some kind of lazy evaluation, in which instead of applying functions to lists that have been completely computed, I have different streams of data that are built on top of each other and, at each moment, only the needed portion of each stream is materialized in main memory. But I have to implement this in Java or C++. So my question is which design pattern or other technique can allow me to implement this lazy processing of streams in one of these languages.

    Read the article

  • IXRepository and test problems

    - by Ridermansb
    Recently had a doubt about how and where to test repository methods. Let the following situation: I have an interface IRepository like this: public interface IRepository<T> where T: class, IEntity { IQueryable<T> Query(Expression<Func<T, bool>> expression); // ... Omitted } And a generic implementation of IRepository public class Repository<T> : IRepository<T> where T : class, IEntity { public IQueryable<T> Query(Expression<Func<T, bool>> expression) { return All().Where(expression).AsQueryable(); } } This is an implementation base that can be used by any repository. It contains the basic implementation of my ORM. Some repositories have specific filters, in which case we will IEmployeeRepository with a specific filter: public interface IEmployeeRepository : IRepository<Employee> { IQueryable<Employee> GetInactiveEmployees(); } And the implementation of IEmployeeRepository: public class EmployeeRepository : Repository<Employee>, IEmployeeRepository // TODO: I have a dependency with ORM at this point in Repository<Employee>. How to solve? How to test the GetInactiveEmployees method { public IQueryable<Employee> GetInactiveEmployees() { return Query(p => p.Status != StatusEmployeeEnum.Active || p.StartDate < DateTime.Now); } } Questions Is right to inherit Repository<Employee>? The goal is to reuse code once all implementing IRepository already been made. If EmployeeRepository inherit only IEmployeeRepository, I have to literally copy and paste the code of Repository<T>. In our example, in EmployeeRepository : Repository<Employee> our Repository lies in our ORM layer. We have a dependency here with our ORM impossible to perform some unit test. How to create a unit test to ensure that the filter GetInactiveEmployees return all Employees in which the Status != Active and StartDate < DateTime.Now. I can not create a Fake/Mock of IEmployeeRepository because I would be testing? Need to test the actual implementation of GetInactiveEmployees. The complete code can be found on Github

    Read the article

  • How should game objects be aware of each other?

    - by Jefffrey
    I find it hard to find a way to organize game objects so that they are polymorphic but at the same time not polymorphic. Here's an example: assuming that we want all our objects to update() and draw(). In order to do that we need to define a base class GameObject which have those two virtual pure methods and let polymorphism kicks in: class World { private: std::vector<GameObject*> objects; public: // ... update() { for (auto& o : objects) o->update(); for (auto& o : objects) o->draw(window); } }; The update method is supposed to take care of whatever state the specific class object needs to update. The fact is that each objects needs to know about the world around them. For example: A mine needs to know if someone is colliding with it A soldier should know if another team's soldier is in proximity A zombie should know where the closest brain, within a radius, is For passive interactions (like the first one) I was thinking that the collision detection could delegate what to do in specific cases of collisions to the object itself with a on_collide(GameObject*). Most of the the other informations (like the other two examples) could just be queried by the game world passed to the update method. Now the world does not distinguish objects based on their type (it stores all object in a single polymorphic container), so what in fact it will return with an ideal world.entities_in(center, radius) is a container of GameObject*. But of course the soldier does not want to attack other soldiers from his team and a zombie doesn't case about other zombies. So we need to distinguish the behavior. A solution could be the following: void TeamASoldier::update(const World& world) { auto list = world.entities_in(position, eye_sight); for (const auto& e : list) if (auto enemy = dynamic_cast<TeamBSoldier*>(e)) // shoot towards enemy } void Zombie::update(const World& world) { auto list = world.entities_in(position, eye_sight); for (const auto& e : list) if (auto enemy = dynamic_cast<Human*>(e)) // go and eat brain } but of course the number of dynamic_cast<> per frame could be horribly high, and we all know how slow dynamic_cast can be. The same problem also applies to the on_collide(GameObject*) delegate that we discussed earlier. So what it the ideal way to organize the code so that objects can be aware of other objects and be able to ignore them or take actions based on their type?

    Read the article

  • How to chain actions/animations together and delay their execution?

    - by codinghands
    I'm trying to build a simple game with a number of screens - 'TitleScreen', 'LoadingScreen', 'PlayScreen', 'HighScoreScreen' - each of which has it's own draw & update logic methods, sprites, other useful fields, etc. This works well for me as a game dev beginner, and it runs. However, on my 'PlayScreen' I want to run some animations before the player gets control - dropping in some artwork, playing some sound effects, generally prettifying things a little. However, I'm not sure what the best way to chain animations / sound effects / other timed general events is. I could make an intermediary screen, 'PrePlayScreen', which simply has all of this hardcoded like so: Update(){ Animation anim1 = new Animation(.....); Animation anim2 = new Animation(.....); anim1.Run(); if(anim1.State == AnimationState.Complete) anim2.Run(); if(anim2.State == AnimationState.Complete) // Load 'PlayScreen' screen } But this doesn't seem so great - surely their must be a better way? I then thought, 'Hey - an AnimationManager! That'd be awesome!'. But then that creeping OOP panic set in as I thought about it some more. If I create the Animation in my Screen, then add it to the AnimationManager (which may or may not be a GameComponent hooked up to Update/Draw), how can I get 'back' to it? To signal commands like start / end / repeat? I'd still need to keep a reference to the object in my Screen so that I could still communicate with it once it's buried in the bosom of a List in my AnimationManager. This seems bad. I've also tried using events - call 'Update' on all the animations in the PlayScreen update loop, but crucially all of the animations have a bool flag ('Active') which determines whether they should begin. The first animation has this set to 'true', all others 'false'. On completion the first animation raises an event, which sets animation 2's bool flag to true (and so it then runs). Once animation 2 is complete another 'anim complete' event is raised, and the screen state changes. Considering the game I'm making is basically as simple as it gets I know I'm overthinking this... it's just the paradigm shift from web - game development is making me break out in a serious case of the stupids.

    Read the article

  • C Programming arrays, I dont understand how I would go about making this program, If anyone can just guide me through the basic outline please :) [on hold]

    - by Rashmi Kohli
    Problem The temperature of a car engine has been measured, from real-world experiments, as shown in the table and graph below: Time (min) Temperature (oC) 0 20 1 36 2 61 3 68 4 77 5 110 Use linear regression to find the engine’s temperature at 1.5 minutes, 4.3 minutes, and any other time specified by the user. Background In engineering, many times we measure several data points in an experiment, but then we need to predict a value that we have not measured which lies between two measured values, such as the problem statement above. If the relation between the measured parameters seems to be roughly linear, then we can use linear regression to find the relationship between those parameters. In the graph of the problem statement above, the relation seems to be roughly linear. Hence, we can apply linear regression to the above problem. Assuming y {y0, y1, …yn-1} has a linear relation with x {x0, x1, … xn-1}, we can say that: y = mx+b where m and b can be found with linear regression as follows: For the problem in this lab, using linear regression gives us the following line (in blue) compared to the measured curve (in red). As you can see, there is usually a difference between the measured values and the estimated (predicted) values. What linear regression does is to minimize those differences and still give us a straight line (blue). Other methods, such as non-linear regression, are also possible to achieve higher accuracy and better curve fitting. Requirements Your program should first print the table of the temperatures similar to the way it’s printed in the problem statement. It should then calculate the temperature at minute 1.5 and 4.3 and show the answers to the user. Next, it should prompt the user to enter a time in minutes (or -1 to quit), and after reading the user’s specified time it should give the value of the engine’s temperature at that time. It should then go back to the prompt. Hints •Use a one dimensional array to store the temperature values given in the problem statement. •Use functions to separate tasks such as calculating m, calculating b, calculating the temperature at a given time, printing the prompt, etc. You can then give your algorithm as well as you pseudo code per function, as opposed to one large algorithm diagram or one large sequence of pseudo code.

    Read the article

  • [EF + Oracle] Inserting Data (1/2)

    - by JTorrecilla
    Prologue Following EF series (I ,II y III) in this chapter we will see how to create DB record from EF. Inserting Data Like we indicated in the 2º post: “One Entity matches with a DB record, and one property match with a Table Column”. To start, we need to create an object from one of the Entities: 1: EMPLEADOS empleado = new EMPLEADOS(); Also like, I told previously, Exists the possibility to use the Static Function defined by VS for each Entity: Once we have created the object, we can Access to it properties to fill like a common class:   1: empleado.NOMBRE = "Javier Torrecilla";   After finish of fill our Entity properties, it must be needed to add the object to the appropriate ObjectSet in the ObjectContext: 1: enti.EMPLEADOS.AddObject(empleado); or 1: enti.AddToEMPLEADOS(empleado); Both methods will do the same action, create an insert statement. Have we finished? No. Any Entity has a property called “EntityState”. This prop is an Enum from “EntityState”, which has the following: Detached: the Entity is created, but not added to the Context. Unchanged: There is no pending changes in the Entity. Added: The entity is added to the ObjectSet, but it is not yet sent to the DB. Deleted: The object is deleted form the ObjectSet, but not yet from the DB. Modified: There is Pending Changes to confirm. Let’s see, the several values of the property during the Creation steps: 1. While the Object is created and we are filling the props: EntityState.Detached; 2. After adding to the ObjectSet: EntityState.Added. This not indicated that the record is in the DB 3. Saving the Data: To sabe the data in the DB, we are going to call “SaveChanges” method of the Object Context. After invoke it, the property will be EntityState.Unchanged.   What does SaveChanges Method? This function will synchronize and send all pending changes to DB. It will add, modify or delete all Entities, whose EntityState property, is setted to Added, Deleted or Modified. After finishing, all added or modified entities will be change the State to “Unchanged”, and deleted Entities must take the “Detached” state.

    Read the article

  • A Simple Entity Tagger

    - by Elton Stoneman
    In the REST world, ETags are your gateway to performance boosts by letting clients cache responses. In the non-REST world, you may also want to add an ETag to an entity definition inside a traditional service contract – think of a scenario where a consumer persists its own representation of your entity, and wants to keep it in sync. Rather than load every entity by ID and check for changes, the consumer can send in a set of linked IDs and ETags, and you can return only the entities where the current ETag is different from the consumer’s version.  If your entity is a projection from various sources, you may not have a persistent ETag, so you need an efficient way to generate an ETag which is deterministic, so an entity with the same state always generates the same ETag. I have an implementation for a generic ETag generator on GitHub here: EntityTagger code sample. The essence is simple - we get the entity, serialize it and build a hash from the serialized value. Any changes to either the state or the structure of the entity will result in a different hash. To use it, just call SetETag, passing your populated object and a Func<> which acts as an accessor to the ETag property: EntityTagger.SetETag(user, x => x.ETag); The implementation is all in at 80 lines of code, which is all pretty straightforward: var eTagProperty = AsPropertyInfo(eTagPropertyAccessor); var originalETag = eTagProperty.GetValue(entity, null); try { ResetETag(entity, eTagPropertyAccessor); string json; var serializer = new DataContractJsonSerializer(entity.GetType()); using (var stream = new MemoryStream()) { serializer.WriteObject(stream, entity); json = Encoding.UTF8.GetString(stream.GetBuffer(), 0, (int)stream.Length); } var guid = GetDeterministicGuid(json); eTagProperty.SetValue(entity, guid.ToString(), null); //... There are a couple of helper methods to check if the object has changed since the ETag value was last set, and to reset the ETag. This implementation uses JSON to do the serializing rather than XML. Benefit - should be marginally more efficient as your hashing a much smaller serialized string; downside, JSON doesn't include namespaces or class names at the root level, so if you have two classes with the exact same structure but different names, then instances which have the same content will have the same ETag. You may want that behaviour, but change to use the XML DataContractSerializer if you think that will be an issue. If you can persist the ETag somewhere, it will save you server processing to load up the entity, but that will only apply to scenarios where you can reliably invalidate your ETag (e.g. if you control all the entry points where entity contents can be updated, then you can calculate and persist the new ETag with each update).

    Read the article

  • Event-Driven Debugging

    - by Brian Donahue
    Most application troubleshooting involves getting an error, analyzing the error message, and at worst, attaching a debugger to work out the real cause. What is not really covered is how to troubleshoot an applicaiton that is not errant, but is having a performance issue, and more than likely, in the middle of the night when you are snug in your bed, sawing logs. What you need is an ever-vigilant cyborg who never sleeps to sit in front of your server all night, but as SkyNet is not live yet, you can settle for the next-best thing. Windows provides performance counters and alerts that can tell you when an applicaiton reaches an unacceptable threshold of naughty behavior, but although it can tattle on your brainchild, it won't be the child psychiatrist that you need to tell you why he's pulling your server's pigtails and pulling faces at the teacher. What you need is to plug a debugger into performance monitor and have it tell you what's going on with your applicaiton at the time. For this purpose, I'd used Microsoft's MDbgEngine as the basis for an applicaiton that will dump a program's stacks, I call it Application Slicer Dicer Wonder Dumper Super Cyborg, or StackOMatic for short. StackOMatic can look at a program's behavior and tell you if the stacks are not moving, but it can also work on the command-line to dump all managed methods on the stack at will. Now that there is a command you can use to dump the stacks, all you need to do is politely tell Windows to run it when you're displeased with your creation as it's trashing the CPU of your server at 3 AM. The first step is to create a scheduled task to tell StackOMatic to dump your applicaiton. Start Task Scheduler and right-click Task Scheduler Library and then Create Task. For this exercise I'm creating a task that will dump the Red Gate SQL Monitor Base Monitor Service. In the Actions tab, I enter the path to StackOMatic and use the arguments to log the stack dump to a file: /PN:RedGate.Response.Engine.Alerting.Base.Service /OUT:c:\users\administrator\MonitorLog.txt Next, I go into Windows Server 2008's Reliability and Performance Monitor and add a new Data Collector Set. This set will produce an alert on the %Processor Time for the service. When the processor time breaches 50%, it will run the StackDumpBaseService task I created. Whenever the service misbehaves, it will append to the log file. Now when I go to work in the morning, I can see what the service was doing when it overloaded the processor and take action.

    Read the article

  • Redesigning an Information System - Part 1

    - by dbradley
    Through the next few weeks or months I'd like to run a small series of articles sharing my experiences from the largest of the project I've worked on and explore some of the real-world problems I've come across and how we went about solving them. I'm afraid I can't give too many specifics on the project right now as it's not yet complete so you'll have to forgive me for being a little abstract in places! To start with I'm going to run through a little of the background of the problem and the motivations to re-design from scratch. Then I'll work through the approaches taken to understanding the requirements, designing, implementing, testing and migrating to the new system. Motivations for Re-designing a Large Information System The system is one that's been in place for a number of years and was originally designed to do a significantly different one to what it's now being used for. This is mainly due to the product maturing as well as client requirements changing. As with most information systems this one can be defined in four main areas of functionality: Input – adding information to the system Storage – persisting information in an efficient, searchable structure Output – delivering the information to the client Control – management of the process There can be a variety of reasons to re-design an existing system; a few of our own turned out to be factors such as: Overall system reliability System response time Failure isolation and recovery Maintainability of code and information General extensibility to solve future problem Separation of business and product concerns New or improved features The factor that started the thought process was the desire to improve the way in which information was entered into the system. However, this alone was not the entire reason for deciding to redesign. Business Drivers Typically all software engineers would always prefer to do a project from scratch themselves. It generally means you don't have to deal with problems created by predecessors and you can create your own absolutely perfect solution. However, the reality of working within a business is that the bottom line comes down to return on investment. For a medium sized business such as mine there must be actual value able to be delivered within a reasonable timeframe for any work to be started. As a result, any long term project will generally take a lot of effort and consideration to be approved by those in charge and therefore it might be better to break down the project into more manageable chunks which allow more frequent deliverables and also value within a shorter timeframe. As the only thing of concern was the methods for inputting information, this is where we started with requirements gathering and design. However knowing that there might be more to the problem and not limiting your design decisions before the requirements is key to finding the best solutions.

    Read the article

  • How should I refactor switch statements like this (Switching on type) to be more OO?

    - by Taytay
    I'm seeing some code like this in our code base, and want to refactor it: (Typescript psuedocode follows): class EntityManager{ private findEntityForServerObject(entityType:string, serverObject:any):IEntity { var existingEntity:IEntity = null; switch(entityType) { case Types.UserSetting: existingEntity = this.getUserSettingByUserIdAndSettingName(serverObject.user_id, serverObject.setting_name); break; case Types.Bar: existingEntity = this.getBarByUserIdAndId(serverObject.user_id, serverObject.id); break; //Lots more case statements here... } return existingEntity; } } The downsides of switching on type are self-explanatory. Normally, when switching behavior based on type, I try to push the behavior into subclasses so that I can reduce this to a single method call, and let polymorphism take care of the rest. However, the following two things are giving me pause: 1) I don't want to couple the serverObject with the class that is storing all of these objects. It doesn't know where to look for entities of a certain type. And unfortunately, the identity of a type of ServerObject varies with the type of ServerObject. (So sometimes it's just an ID, other times it's a combination of an id and a uniquely identifying string, etc). And this behavior doesn't belong down there on those subclasses. It is the responsibility of the EntityManager and its delegates. 2) In this case, I can't modify the ServerObject classes since they're plain old data objects. It should be mentioned that I've got other instances of the above method that take a parameter like "IEntity" and proceed to do almost the same thing (but slightly modify the name of the methods they're calling to get the identity of the entity). So, we might have: case Types.Bar: existingEntity = this.getBarByUserIdAndId(entity.getUserId(), entity.getId()); break; So in that case, I can change the entity interface and subclasses, but this isn't behavior that belongs in that class. So, I think that points me to some sort of map. So eventually I will call: private findEntityForServerObject(entityType:string, serverObject:any):IEntity { return aMapOfSomeSort[entityType].findByServerObject(serverObject); } private findEntityForEntity(someEntity:IEntity):IEntity { return aMapOfSomeSort[someEntity.entityType].findByEntity(someEntity); } Which means I need to register some sort of strategy classes/functions at runtime with this map. And again, I darn well better remember to register one for each my my types, or I'll get a runtime exception. Is there a better way to refactor this? I feel like I'm missing something really obvious here.

    Read the article

  • Is the Observer pattern adequate for this kind of scenario?

    - by Omega
    I'm creating a simple game development framework with Ruby. There is a node system. A node is a game entity, and it has position. It can have children nodes (and one parent node). Children are always drawn relatively to their parent. Nodes have a @position field. Anyone can modify it. When such position is modified, the node must update its children accordingly to properly draw them relatively to it. @position contains a Point instance (a class with x and y properties, plus some other useful methods). I need to know when a node's @position's state changes, so I can tell the node to update its children. This is easy if the programmer does something like this: @node.position = Point.new(300,300) Because it is equivalent to calling this: # Code in the Node class def position=(newValue) @position = newValue update_my_children # <--- I know that the position changed end But, I'm lost when this happens: @node.position.x = 300 The only one that knows that the position changed is the Point instance stored in the @position property of the node. But I need the node to be notified! It was at this point that I considered the Observer pattern. Basically, Point is now observable. When a node's position property is given a new Point instance (through the assignment operator), it will stop observing the previous Point it had (if any), and start observing the new one. When a Point instance gets a state change, all observers (the node owning it) will be notified, so now my node can update its children when the position changes. A problem is when this happens: @someNode.position = @anotherNode.position This means that two nodes are observing the same point. If I change one of the node's position, the other would change as well. To fix this, when a position is assigned, I plan to create a new Point instance, copy the passed argument's x and y, and store my newly created point instead of storing the passed one. Another problem I fear is this: somePoint = @node.position somePoint.x = 500 This would, technically, modify @node's position. I'm not sure if anyone would be expecting that behavior. I'm under the impression that people see Point as some kind of primitive rather than an actual object. Is this approach even reasonable? Reasons I'm feeling skeptical: I've heard that the Observer pattern should be used with, well, many observers. Technically, in this scenario there is only one observer at a time. When assigning a node's position as another's (@someNode.position = @anotherNode.position), where I create a whole new instance rather than storing the passed point, it feels hackish, or even inefficient.

    Read the article

  • Is this a valid implementation of the repository pattern?

    - by user1578653
    I've been reading up about the repository pattern, with a view to implementing it in my own application. Almost all examples I've found on the internet use some kind of existing framework rather than showing how to implement it 'from scratch'. Here's my first thoughts of how I might implement it - I was wondering if anyone could advise me on whether this is correct? I have two tables, named CONTAINERS and BITS. Each CONTAINER can contain any number of BITs. I represent them as two classes: class Container{ private $bits; private $id; //...and a property for each column in the table... public function __construct(){ $this->bits = array(); } public function addBit($bit){ $this->bits[] = $bit; } //...getters and setters... } class Bit{ //some properties, methods etc... } Each class will have a property for each column in its respective table. I then have a couple of 'repositories' which handle things to do with saving/retrieving these objects from the database: //repository to control saving/retrieving Containers from the database class ContainerRepository{ //inject the bit repository for use later public function __construct($bitRepo){ $this->bitRepo = $bitRepo; } public function getById($id){ //talk directly to Oracle here to all column data into the object //get all the bits in the container $bits = $this->bitRepo->getByContainerId($id); foreach($bits as $bit){ $container->addBit($bit); } //return an instance of Container } public function persist($container){ //talk directly to Oracle here to save it to the database //if its ID is NULL, create a new container in database, otherwise update the existing one //use BitRepository to save each of the Bits inside the Container $bitRepo = $this->bitRepo; foreach($container->bits as $bit){ $bitRepo->persist($bit); } } } //repository to control saving/retrieving Bits from the database class BitRepository{ public function getById($id){} public function getByContainerId($containerId){} public function persist($bit){} } Therefore, the code I would use to get an instance of Container from the database would be: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = $containerRepo->getById($id); Or to create a new one and save to the database: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = new Container(); $container->setSomeProperty(1); $bit = new Bit(); $container->addBit($bit); $containerRepo->persist($container); Can someone advise me as to whether I have implemented this pattern correctly? Thanks!

    Read the article

  • Trying to find resources to learn how to test software [closed]

    - by Davek804
    First off, yes this is a general question, and I'd be perfectly happy to move this to another portion of SE, but I didn't see a more fitting sub. Basically, I am hoping a more experienced QA tester can come along and really fill in some basics for me. So far, websites seem to be sparse in terms of explaining languages involved, basic practices, etc. So, I'm sorry in advance if this is too general, but towards the end of this post I ask some specific questions if it's just absolutely unacceptable to speak in general terms. I just landed a position as Junior Systems and QA Engineer with a social media startup. Their QA and testing is almost nonexistent, so if I do a good job, I imagine I'll find a lot of bugs and have a secure role in the business. I'm pretty good with the systems aspect of my role, but I need to learn more about the QA and testing aspects. We run hardware that's touchscreen based - the user can use and interact with the devices. So, in terms of my QA role, in the short term, I need to build scripts to test the hardware/software as a 'user' to try to uncover bugs. First off, what language should these scripts be written in? Does anyone have some examples? What about the longer term 'automated testing'? I'm familiar with regression testing as the developer adds in new features, sure, but the 50,000 other types of testing, not so much. Most of our hardware runs dotnet/C# code, with some of the servers running Java - but I don't expect to need to run tests on the Java side at this point. I hope to meet with one developer today and try to get a good idea of the output from the hardware so that I can 'mock' this data that gets sent to servers, to try to bugtest. Eventually, we will be moving the hardware to be closer to where I live and work, so that I can test virtually and on real hardware. So a lot of the bugs we're dealing with now are like this: the Local Server, which kiosks report their data to gets updated from the kiosks, but the remote server does not. Or, vis versa when the user registers on a kiosk, the remote server updates but the local server does not. But yeah, without much more detail, I imagine a lot of this info isn't helpful. I've bought a book "How Google Tests Software", but it's really a book more about 'how their software testing is different from Microsoft'. It doesn't teach how to test so much as why their methods are better. Does anyone have a good book that I can buy? An ebook maybe? My local Barnes and Noble kinda had a terrible selection. I also figure a book from 2005 is not necessarily that good either.

    Read the article

  • Push Trunk or Push Branch to Production

    - by coffeeaddict
    I'd like to get an idea of some processes on build process with Tortoise SVN. Primarily I'm wondering do you push: The Mainline Trunk A branch after QA has grabbed it into a working copy locally and tested the branch and then some build pushes that branch The problem I have is I work at a craphole (hey, it is what it is and I'm venting on stackoverflow, you better believe it..good way to relieve stress due to complete utter chaos) and we have no formal process for pushing anything. In fact even worse my boss directly codes against production. When I have changes, he pushes the mainline trunk. The problem becomes when I make database changes on our Dev database for lets say Branch A. Well...that breaks Branch B and C. I have like 4 projects going on at once! Why? Well, I will not get into that (chaos). So consequently I rename a table field, or add a field or whatever in SQL Server and walla, now my other branches have stale code pointing to previous field names. So what happens? I have to merge certain changes to this branch, to that branch, etc. It feels like a war zone. Finally, what happens is I try to only merge the minimum. Lets say I made DB changes for Branch A's code but now I had to jump back on Branch B's project. Well I need to merge "some" of A's changes over for those database changes so that B's code is not going to bomb out and is able to work with the new table changes. Finally boss pushes the mainline trunk to production. Now I get an email "you forgot to remove the hyperlink for this". That hyperlink was actually a feature I added in Branch A. But what he's talking about here is he just pushed the mainline trunk to production which now has my merged changes from Branch B and any database scripts for Branch A because remember I had some DB changes and if he pushes code, it's got to reflect those changes thus some partial database changes must also be pushed even if it's not related to this project. Well...I missed the hyperlink, so kill me. Maybe that's why we need a build process boss? (sorry, it's been a nightmare working here which is why this thread is getting so detailed). Anyway, obviously this is a nightmare. And he dictates almost everything. The only reason we have source control is because I've worked on hard core teams and that's the first thing you setup. Well there was none here. Problem is I can't dictate the structure..he does but he's never really used source control!! My God. So we have no QA. This is an e-commerce website. That's another huge issue. So consequently I'm expected to be perfect. That means mainline trunk needs to be perfect for whatever we're pushing, whatever branch feature. Is this luda? wtf do I do? I could go off on him after tying so many times tactfully to explain that we need a freakin build process (not just copy local mainline trunk to production!) but I've tried to push before and got yelled at. So I gave up on that. So it will help me tremendously to know how others are pushing their source from Tortoise to production. I was not the person pushing when I was on previous teams so really I'm not too versed in build processes. We are a fairly good size e-commerce site and get a couple millions hits a month.

    Read the article

  • The HTML5 doctype is not triggering standards mode in IE8

    - by El Guapo
    i work for a company where all our sites currently use the XHTML 1.0 transitional doctype (yes i know it is very old school). I want to change them all to use the HTML5 doctype seeing as it is backwards compatible. One of the reasons why i want to make the switch is because in IE8 if someone has the developer tools installed then the old XHTML doctype switches the browser into compatibility mode and renders the page as IE7. From reading up on it i was led to believe that the HTML5 doctype will set any page to render in standards mode, but this is not happening when i test it on our staging server it still flips into IE7 rendering mode. The weird thing is if i save the page with HTML5 doctype locally and open it, it is rendering in IE8 standards mode. There must be something else causing it to drop into compatibility IE7 rendering. Any ideas what this could be? Below is the head of the test page i have been looking at: <!DOCTYPE html > <html xmlns="http://www.w3.org/1999/xhtml" xmlns:og="http://opengraphprotocol.org/schema/" xmlns:fb="http://www.facebook.com/2008/fbml"> <head> <title>Burton - Mens Clothing - Mens Fashion - Burton Menswear</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="description" content="Burton is one of the UK's leading men's clothing &amp; fashion retailers, with a range of men's clothing designed to make you look &amp; feel good. Find formal &amp; casual clothes &amp; accessories for men online at Burton menswear"/> <meta name="keywords" content="menswear, clothes for men, clothing for men, men clothes, men's fashion, men's wear, men's clothing online, men's clothes online, men's clothes shop, burton men's, burton menswear, burton uk, burton"/> <script type="text/javascript">document.getElementsByTagName('html')[0].className = 'js';</script> <link rel="stylesheet" type="text/css" href="http://eu.burton-menswear.com/wcsstore/ConsumerDirectStorefrontAssetStore/images/colors/color2/v3/css/screen.css" /> <link rel="stylesheet" type="text/css" href="http://eu.burton-menswear.com/wcsstore/ConsumerDirectStorefrontAssetStore/images/colors/color2/v3/css/print.css" media="print"/> <link rel="stylesheet" type="text/css" href="http://eu.burton-menswear.com/wcsstore/ConsumerDirectStorefrontAssetStore/images/colors/color2/v3/css/brand.css" /> <!--[if lt IE 8]> <link rel="stylesheet" href="http://eu.burton-menswear.com/wcsstore/ConsumerDirectStorefrontAssetStore/images/colors/color2/v3/css/ie.css" type="text/css" media="screen, projection"> <![endif]--> <meta http-equiv="content-language" content="en-gb" /> <link rel="shortcut icon" type="image/x-icon" href="http://eu.burton-menswear.com/favicon.ico" /> <link rel="search" type="application/opensearchdescription+xml" title="burton.co.uk Search" href="http://eu.burton-menswear.com/burton-search.xml"/> <!-- Start Summit Tag --> <script type="text/javascript"> var __stormJs = "t1.stormiq.com/dcv4/jslib/3286_D92B7532_4A18_46A8_864A_5FDF1DF25844.js"; </script> <script type="text/javascript" src="http://eu.burton-menswear.com/javascript/track.js"></script> <!-- End Summit Tag --> <!-- Start QuBit Tag --> <script src=//d3c3cq33003psk.cloudfront.net/opentag-31935-42109.js async defer></script> <!-- End QuBit Tag --> <link type="text/css" rel="stylesheet" href="http://reviews.br.wcstage.arcadiagroup.ltd.uk/bvstaging/static/6028-en_gb/bazaarvoice.css" ></link> </head>

    Read the article

  • Code Golf: Finite-state machine!

    - by Adam Matan
    Finite state machine A deterministic finite state machine is a simple computation model, widely used as an introduction to automata theory in basic CS courses. It is a simple model, equivalent to regular expression, which determines of a certain input string is Accepted or Rejected. Leaving some formalities aside, A run of a finite state machine is composed of: alphabet, a set of characters. states, usually visualized as circles. One of the states must be the start state. Some of the states might be accepting, usually visualized as double circles. transitions, usually visualized as directed arches between states, are directed links between states associated with an alphabet letter. input string, a list of alphabet characters. A run on the machine begins at the starting state. Each letter of the input string is read; If there is a transition between the current state and another state which corresponds to the letter, the current state is changed to the new state. After the last letter was read, if the current state is an accepting state, the input string is accepted. If the last state was not an accepting state, or a letter had no corresponding arch from a state during the run, the input string is rejected. Note: This short descruption is far from being a full, formal definition of a FSM; Wikipedia's fine article is a great introduction to the subject. Example For example, the following machine tells if a binary number, read from left to right, has an even number of 0s: The alphabet is the set {0,1}. The states are S1 and S2. The transitions are (S1, 0) -> S2, (S1, 1) -> S1, (S2, 0) -> S1 and (S2, 1) -> S2. The input string is any binary number, including an empty string. The rules: Implement a FSM in a language of your choice. Input The FSM should accept the following input: <States> List of state, separated by space mark. The first state in the list is the start state. Accepting states begin with a capital letter. <transitions> One or more lines. Each line is a three-tuple: origin state, letter, destination state) <input word> Zero or more characters, followed by a newline. For example, the aforementioned machine with 1001010 as an input string, would be written as: S1 s2 S1 0 s2 S1 1 S1 s2 0 S1 s2 1 s2 1001010 Output The FSM's run, written as <State> <letter> -> <state>, followed by the final state. The output for the example input would be: S1 1 -> S1 S1 0 -> s2 s2 0 -> S1 S1 1 -> S1 S1 0 -> s2 s2 1 -> s2 s2 0 -> S1 ACCEPT For the empty input '': S1 ACCEPT For 101: S1 1 -> S1 S1 0 -> s2 s2 1 -> s2 REJECT For '10X': S1 1 -> S1 S1 0 -> s2 s2 X REJECT Prize A nice bounty will be given to the most elegant and short solution. Reference implementation A reference Python implementation will be published soon.

    Read the article

< Previous Page | 335 336 337 338 339 340 341 342 343 344 345 346  | Next Page >