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  • Equal Gifts Algorithm Problem

    - by 7Aces
    Problem Link - http://opc.iarcs.org.in/index.php/problems/EQGIFTS It is Lavanya's birthday and several families have been invited for the birthday party. As is customary, all of them have brought gifts for Lavanya as well as her brother Nikhil. Since their friends are all of the erudite kind, everyone has brought a pair of books. Unfortunately, the gift givers did not clearly indicate which book in the pair is for Lavanya and which one is for Nikhil. Now it is up to their father to divide up these books between them. He has decided that from each of these pairs, one book will go to Lavanya and one to Nikhil. Moreover, since Nikhil is quite a keen observer of the value of gifts, the books have to be divided in such a manner that the total value of the books for Lavanya is as close as possible to total value of the books for Nikhil. Since Lavanya and Nikhil are kids, no book that has been gifted will have a value higher than 300 Rupees... For the problem, I couldn't think of anything except recursion. The code I wrote is given below. But the problem is that the code is time-inefficient and gives TLE (Time Limit Exceeded) for 9 out of 10 test cases! What would be a better approach to the problem? Code - #include<cstdio> #include<climits> #include<algorithm> using namespace std; int n,g[150][2]; int diff(int a,int b,int f) { ++f; if(f==n) { if(a>b) { return a-b; } else { return b-a; } } return min(diff(a+g[f][0],b+g[f][1],f),diff(a+g[f][1],b+g[f][0],f)); } int main() { int i; scanf("%d",&n); for(i=0;i<n;++i) { scanf("%d%d",&g[i][0],&g[i][1]); } printf("%d",diff(g[0][0],g[0][1],0)); } Note - It is just a practice question, & is not part of a competition.

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  • Devoxx 2011: Java EE 6 Hands-on Lab Delivered

    - by arungupta
    I, along with Alexis's help, delivered a Java EE 6 hands-on lab to a packed room of about 40+ attendees at Devoxx 2011. The lab was derived from the OTN Developer Days 2012 version but added lot more content to showcase several Java EE 6 technologies. The problem statement from the lab document states: This hands-on lab builds a typical 3-tier Java EE 6 Web application that retrieves customer information from a database and displays it in a Web page. The application also allows new customers to be added to the database as well. The string-based and type-safe queries are used to query and add rows to the database. Each row in the database table is published as a RESTful resource and is then accessed programmatically. Typical design patterns required by a Web application like validation, caching, observer, partial page rendering, and cross-cutting concerns like logging are explained and implemented using different Java EE 6 technologies. The lab covered Java Persistence API 2, Servlet 3, Enterprise JavaBeans 3.1, JavaServer Faces 2, Java API for RESTful Web Services 1.1, Contexts and Dependency Injection 1.0, and Bean Validation 1.0 over 47 pages of detailed self-paced instructions. Here is the complete Table of Contents: The lab can be downloaded from here and requires only NetBeans IDE "All" or "Java EE" version, which includes GlassFish anyway. All the feedback received from the lab has been incorporated in the instructions and bugs filed (Updated 49559, 205232, 205248, 205256). 80% of the attendees could easily complete the lab and some even completed in much less than 3 hours. That indicates that either more content needs to be added to the lab or the intellectual level of the attendees at the conference was pretty high. I think the lab has enough content for 3 hours but we moved at a much more faster pace so I conclude on the latter. Truly a joy to conduct a lab to 40 Devoxxians! Another related lab that might be handy for folks is "Develop, Deploy, and Monitor your Java EE 6 applications using GlassFish 3.1 Cluster". It explains how: Create a 2-instance GlassFish cluster Front-end with a Web server and a load balancer Demonstrate session replication and fail over Monitor the application using JavaScript The complete lab instructions and source code are available and you can try them. I plan to continue evolving the contents for the Java EE 6 hands-on lab to cover more technologies and features and will announce them on this blog. Let me know on what else would you like to see in the future versions.

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  • Devoxx 2011: Java EE 6 Hands-on Lab Delivered

    - by arungupta
    I, along with Alexis's help, delivered a Java EE 6 hands-on lab to a packed room of about 40+ attendees at Devoxx 2011. The lab was derived from the OTN Developer Days 2012 version but added lot more content to showcase several Java EE 6 technologies. The problem statement from the lab document states: This hands-on lab builds a typical 3-tier Java EE 6 Web application that retrieves customer information from a database and displays it in a Web page. The application also allows new customers to be added to the database as well. The string-based and type-safe queries are used to query and add rows to the database. Each row in the database table is published as a RESTful resource and is then accessed programmatically. Typical design patterns required by a Web application like validation, caching, observer, partial page rendering, and cross-cutting concerns like logging are explained and implemented using different Java EE 6 technologies. The lab covered Java Persistence API 2, Servlet 3, Enterprise JavaBeans 3.1, JavaServer Faces 2, Java API for RESTful Web Services 1.1, Contexts and Dependency Injection 1.0, and Bean Validation 1.0 over 47 pages of detailed self-paced instructions. Here is the complete Table of Contents: The lab can be downloaded from here and requires only NetBeans IDE "All" or "Java EE" version, which includes GlassFish anyway. All the feedback received from the lab has been incorporated in the instructions and bugs filed (Updated 49559, 205232, 205248, 205256). 80% of the attendees could easily complete the lab and some even completed in much less than 3 hours. That indicates that either more content needs to be added to the lab or the intellectual level of the attendees at the conference was pretty high. I think the lab has enough content for 3 hours but we moved at a much more faster pace so I conclude on the latter. Truly a joy to conduct a lab to 40 Devoxxians! Another related lab that might be handy for folks is "Develop, Deploy, and Monitor your Java EE 6 applications using GlassFish 3.1 Cluster". It explains how: Create a 2-instance GlassFish cluster Front-end with a Web server and a load balancer Demonstrate session replication and fail over Monitor the application using JavaScript The complete lab instructions and source code are available and you can try them. I plan to continue evolving the contents for the Java EE 6 hands-on lab to cover more technologies and features and will announce them on this blog. Let me know on what else would you like to see in the future versions.

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  • How do we keep dependent data structures up to date?

    - by Geo
    Suppose you have a parse tree, an abstract syntax tree, and a control flow graph, each one logically derived from the one before. In principle it is easy to construct each graph given the parse tree, but how can we manage the complexity of updating the graphs when the parse tree is modified? We know exactly how the tree has been modified, but how can the change be propagated to the other trees in a way that doesn't become difficult to manage? Naturally the dependent graph can be updated by simply reconstructing it from scratch every time the first graph changes, but then there would be no way of knowing the details of the changes in the dependent graph. I currently have four ways to attempt to solve this problem, but each one has difficulties. Nodes of the dependent tree each observe the relevant nodes of the original tree, updating themselves and the observer lists of original tree nodes as necessary. The conceptual complexity of this can become daunting. Each node of the original tree has a list of the dependent tree nodes that specifically depend upon it, and when the node changes it sets a flag on the dependent nodes to mark them as dirty, including the parents of the dependent nodes all the way down to the root. After each change we run an algorithm that is much like the algorithm for constructing the dependent graph from scratch, but it skips over any clean node and reconstructs each dirty node, keeping track of whether the reconstructed node is actually different from the dirty node. This can also get tricky. We can represent the logical connection between the original graph and the dependent graph as a data structure, like a list of constraints, perhaps designed using a declarative language. When the original graph changes we need only scan the list to discover which constraints are violated and how the dependent tree needs to change to correct the violation, all encoded as data. We can reconstruct the dependent graph from scratch as though there were no existing dependent graph, and then compare the existing graph and the new graph to discover how it has changed. I'm sure this is the easiest way because I know there are algorithms available for detecting differences, but they are all quite computationally expensive and in principle it seems unnecessary so I'm deliberately avoiding this option. What is the right way to deal with these sorts of problems? Surely there must be a design pattern that makes this whole thing almost easy. It would be nice to have a good solution for every problem of this general description. Does this class of problem have a name?

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  • Event Driven Behavior Tree: deterministic traversal order with parallel

    - by Heisenbug
    I've studied several articles and listen some talks about behavior trees (mostly the resources available on AIGameDev by Alex J. Champandard). I'm particularly interested on event driven behavior trees, but I have still some doubts on how to implement them correctly using a scheduler. Just a quick recap: Standard Behavior Tree Each execution tick the tree is traversed from the root in depth-first order The execution order is implicitly expressed by the tree structure. So in the case of behaviors parented to a parallel node, even if both children are executed during the same traversing, the first leaf is always evaluated first. Event Driven BT During the first traversal the nodes (tasks) are enqueued using a scheduler which is responsible for updating only running ones every update The first traversal implicitly produce a depth-first ordered queue in the scheduler Non leaf nodes stays suspended mostly of the time. When a leaf node terminate(either with success or fail status) the parent (observer) is waked up allowing the tree traversing to continue and new tasks will be enqueued in the scheduler Without parallel nodes in the tree there will be up to 1 task running in the scheduler Without parallel nodes, the tasks in the queue(excluding dynamic priority implementation) will be always ordered in a depth-first order (is this right?) Now, from what is my understanding of a possible implementation, there are 2 requirements I think must be respected(I'm not sure though): Now, some requirements I think needs to be guaranteed by a correct implementation are: The result of the traversing should be independent from which implementation strategy is used. The traversing result must be deterministic. I'm struggling trying to guarantee both in the case of parallel nodes. Here's an example: Parallel_1 -->Sequence_1 ---->leaf_A ---->leaf_B -->leaf_C Considering a FIFO policy of the scheduler, before leaf_A node terminates the tasks in the scheduler are: P1(suspended),S1(suspended),leaf_A(running),leaf_C(running) When leaf_A terminate leaf_B will be scheduled (at the end of the queue), so the queue will become: P1(suspended),S1(suspended),leaf_C(running),leaf_B(running) In this case leaf_B will be executed after leaf_C at every update, meanwhile with a non event-driven traversing from the root node, the leaf_B will always be evaluated before leaf_A. So I have a couple of question: do I have understand correctly how event driven BT work? How can I guarantee the depth first order is respected with such an implementation? is this a common issue or am I missing something?

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  • JCP.next.3: time to get to work

    - by Patrick Curran
    As I've previously reported in this blog, we planned three JSRs to improve the JCP’s processes and to meet our members’ expectations for change. The first - JCP.next.1, or more formally JSR 348: Towards a new version of the Java Community Process - was completed in October 2011. This focused on a small number of simple but important changes to make our process more transparent and to enable broader participation. We're already seeing the benefits of these changes as new and existing JSRs adopt the new requirements. However, because we wanted to complete this JSR quickly we deliberately postponed a number of more complex items, including everything that would require modifying the JSPA (the legal agreement that members sign when they join the organization) to a follow-on JSR. The second JSR (JSR 355: JCP Executive Committee Merge) is in progress now and will complete later this year. This JSR is even simpler than the first, and is focused solely on merging the two Executive Committees into one for greater efficiency and to encourage synergies between the Java ME and Java SE platforms. Continuing the momentum to move Java and the JCP forward we have just filed the third JSR (JCP.next.3) as JSR 358: A major revision of the Java Community Process. This JSR will modify the JSPA as well as the Process Document, and will tackle a large number of complex issues, many of them postponed from JSR 348. For these reasons we expect to spend a considerable amount of time working on it - at least a year, and probably more. The current version of the JSPA was created back in 2002, although some minor changes were introduced in 2005. Since then the organization and the environment in which we operate have changed significantly, and it is now time to revise our processes to ensure that they meet our current needs. We have a long list of topics to be considered, including the role of independent implementations (those not derived from the Reference Implementation), licensing and open source, ensuring that our new transparency requirements are implemented correctly, compatibility policy and TCKs, the role of individual members, patent policy, and IP flow. The Expert Group for JSR 358, as with all process-change JSRs, consists of all members of the Executive Committees. Even though the JSR has just been filed we started discussions on the various topics several months ago (see the EC's meeting minutes for details) and our EC members - including the new members who joined within the last year or two - are actively engaged. Now it's your opportunity to get involved. As required by version 2.8 of our Process (introduced with JSR 348) we will conduct all our business in the open. We have a public java.net project where you can follow and participate in our work. All of our deliberations will be copied to a public Observer mailing list, we'll track our issues on a public Issue Tracker, and all our documents (meeting agendas and minutes, task lists, working drafts) will be published in our Document Archive. We're just getting started, but we do want your input. Please visit us on java.net where you can learn how to participate. Let's get to work...

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  • How do i return integers from a string ?

    - by kannan.ambadi
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Suppose you are passing a string(for e.g.: “My name has 1 K, 2 A and 3 N”)  which may contain integers, letters or special characters. I want to retrieve only numbers from the input string. We can implement it in many ways such as splitting the string into an array or by using TryParse method. I would like to share another idea, that’s by using Regular expressions. All you have to do is, create an instance of Regular Expression with a specified pattern for integer. Regular expression class defines a method called Split, which splits the specified input string based on the pattern provided during object initialization.     We can write the code as given below:   public static int[] SplitIdSeqenceValues(object combinedArgs)         {             var _argsSeperator = new Regex(@"\D+", RegexOptions.Compiled);               string[] splitedIntegers = _argsSeperator.Split(combinedArgs.ToString());               var args = new int[splitedIntegers.Length];               for (int i = 0; i < splitedIntegers.Length; i++)                 args[i] = MakeSafe.ToSafeInt32(splitedIntegers[i]);                           return args;         }    It would be better, if we set to RegexOptions.Compiled so that the regular expression will have performance boost by faster compilation.   Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Happy Programming  :))   

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  • C# 5 Async, Part 1: Simplifying Asynchrony – That for which we await

    - by Reed
    Today’s announcement at PDC of the future directions C# is taking excite me greatly.  The new Visual Studio Async CTP is amazing.  Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability.  This is handled by building on the Task functionality in .NET 4, as well as the addition of two new keywords being added to the C# language: async and await. This core of the new asynchronous functionality is built upon three key features.  First is the Task functionality in .NET 4, and based on Task and Task<TResult>.  While Task was intended to be the primary means of asynchronous programming with .NET 4, the .NET Framework was still based mainly on the Asynchronous Pattern and the Event-based Asynchronous Pattern. The .NET Framework added functionality and guidance for wrapping existing APIs into a Task based API, but the framework itself didn’t really adopt Task or Task<TResult> in any meaningful way.  The CTP shows that, going forward, this is changing. One of the three key new features coming in C# is actually a .NET Framework feature.  Nearly every asynchronous API in the .NET Framework has been wrapped into a new, Task-based method calls.  In the CTP, this is done via as external assembly (AsyncCtpLibrary.dll) which uses Extension Methods to wrap the existing APIs.  However, going forward, this will be handled directly within the Framework.  This will have a unifying effect throughout the .NET Framework.  This is the first building block of the new features for asynchronous programming: Going forward, all asynchronous operations will work via a method that returns Task or Task<TResult> The second key feature is the new async contextual keyword being added to the language.  The async keyword is used to declare an asynchronous function, which is a method that either returns void, a Task, or a Task<T>. Inside the asynchronous function, there must be at least one await expression.  This is a new C# keyword (await) that is used to automatically take a series of statements and break it up to potentially use discontinuous evaluation.  This is done by using await on any expression that evaluates to a Task or Task<T>. For example, suppose we want to download a webpage as a string.  There is a new method added to WebClient: Task<string> WebClient.DownloadStringTaskAsync(Uri).  Since this returns a Task<string> we can use it within an asynchronous function.  Suppose, for example, that we wanted to do something similar to my asynchronous Task example – download a web page asynchronously and check to see if it supports XHTML 1.0, then report this into a TextBox.  This could be done like so: private async void button1_Click(object sender, RoutedEventArgs e) { string url = "http://reedcopsey.com"; string content = await new WebClient().DownloadStringTaskAsync(url); this.textBox1.Text = string.Format("Page {0} supports XHTML 1.0: {1}", url, content.Contains("XHTML 1.0")); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Let’s walk through what’s happening here, step by step.  By adding the async contextual keyword to the method definition, we are able to use the await keyword on our WebClient.DownloadStringTaskAsync method call. When the user clicks this button, the new method (Task<string> WebClient.DownloadStringTaskAsync(string)) is called, which returns a Task<string>.  By adding the await keyword, the runtime will call this method that returns Task<string>, and execution will return to the caller at this point.  This means that our UI is not blocked while the webpage is downloaded.  Instead, the UI thread will “await” at this point, and let the WebClient do it’s thing asynchronously. When the WebClient finishes downloading the string, the user interface’s synchronization context will automatically be used to “pick up” where it left off, and the Task<string> returned from DownloadStringTaskAsync is automatically unwrapped and set into the content variable.  At this point, we can use that and set our text box content. There are a couple of key points here: Asynchronous functions are declared with the async keyword, and contain one or more await expressions In addition to the obvious benefits of shorter, simpler code – there are some subtle but tremendous benefits in this approach.  When the execution of this asynchronous function continues after the first await statement, the initial synchronization context is used to continue the execution of this function.  That means that we don’t have to explicitly marshal the call that sets textbox1.Text back to the UI thread – it’s handled automatically by the language and framework!  Exception handling around asynchronous method calls also just works. I’d recommend every C# developer take a look at the documentation on the new Asynchronous Programming for C# and Visual Basic page, download the Visual Studio Async CTP, and try it out.

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  • Vim Regex to replace tags

    - by Rudiger Wolf
    I am lookin for a regex express to remove the email addresses from a text file. Input file: Hannah Churchman <[email protected]>; Julie Drew <[email protected]>; Output file: Hannah Churchman; Julie Drew; I thought a generic regex shuch as s/<(.*?)//g would be a good starting point but I am unable to find the right expression for use Vim? something like :%s/ <\(.*?\)>//g does not work. Error is "E486: Pattern not found:". :%s#[^ <]*>##g almost works but it leaves the space and < behind. :%s# <##g to remove the " <" remaining stuff. Any tips on how to better craft this command?

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  • Podcast: Advanced MVVM with Josh Smith

    - by craigshoemaker
    Author, Microsoft MVP and accomplished pianist Josh Smith, Sr. UX Developer at IdentityMine, joins the show to discuss some of Model View ViewModel’s more advanced scenarios. Full Speed: download Fast Version: download Josh shares is experience using MVVM gives some real-world advice on: Using modal dialogs Evils and virtues of code behind in views Use of attached behaviors Undo/redo strategies Working with animations Building a task based architecture for managing communication between View and ViewModel Frameworks in the MVVM space The Book Get first-hand experience implementing the solutions to the challenges discussed in the show by reading Josh’s new book ‘Advanced MVVM’. Resources The following resources are mentioned in the show: Laurent Bugnion's mix talk ‘Understanding the Model-View-ViewModel Pattern Josh Smith’s MVVM Foundation Laurent Bugnion’s MVVM Light framework Rob Eisenberg's Caliburn

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  • Silverlight 5 Hosting :: Features in Silverlight 5 and Release Date

    - by mbridge
    Silverlight 5 is finally announced in the Silverlight FireStarter Event on the 2nd December, 2010. This new version of Silverlight which was earlier labeled as 'Future of Microsoft Silverlight' has now come much closer to go live as the first Silverlight 5 Beta version is expected to be shipped during the early months of 2011. However for the full fledged and the final release of Silverlight 5, we have to wait many more months as the same is likely to be made available within the Q3 2011. As would have been usually expected, this latest edition would feature many new capabilities thereby extending the developer productivity to a whole new dimension of premium media experience and feature-rich business applications. It comes along with many new feature updates as well as the inclusion of new technologies to improve the standard of the Silverlight applications which are now fine-tuned to produce next generation business and media solutions that is capable to meet the requirements of the advanced web-based app development. The Silverlight 5 is all set to replace the previous fourth version which now includes more than forty new features while also dropping various deprecated elements that was prevalent earlier. It has brought around some major performance enhancements and also included better support for various other tools and technologies. Following are some of the changes that are registered to be available under the Silverlight 5 Beta edition which is scheduled to be launched during the Q1 2011. Silverlight 5 : Premium Media Experiences The media features of Silverlight 5 has seen some major enhancements with a lot of optimizations being made to deliver richer solutions. It's capability has now been extended to make things easier, faster and capable of performing the desired tasks in the most efficient manner. The Silverlight media solutions has already been a part of many companies in the recent days where various on-demand Silverlight services were featured but with the arrival of the next generation premium media solution of Silverlight 5, it is expected to register new heights of success and global user acclamation for using it with many esteemed web-based projects and media solutions. - The most happening element in the new Silverlight 5 will be its support for utilizing the GPU based hardware acceleration which is intended to lower down the CPU load to a significant extent and thereby allowing faster rendering of media contents without consuming much resources. This feature is believed to be particularly helpful for low configured machines to run full HD media content without any lagging caused due to processor load. It will hence be one great feature to revolutionize the new generation high quality media contents to be available within the web in a more efficient manner with its hardware decoded video playback capabilities. - With the inclusion of hardware video decoding to minimize the processor load, the Silverlight 5 also comes with another optimization enhancement to also reduce the power consumption level by making new methods to deal with the power-saver settings. With this optimization in effect, the computer would be automatically allowed to switch to sleep mode while no video playback is in progress and also to prevent any screensavers to popup and cause annoyances during any video playback. There would also be other power saver options which will be made available to best suit the users requirements and purpose. - The Silverlight trickplay feature is another great way to tweak any silverlight powered media content as is used for many video tutorial sites or for dealing with any sort of presentations. This feature enables the user to modify the playback speed to either slowdown or speedup during the playback durations based on the requirements without compromising on the quality of output. Normally such manipulations always makes the content's audio to go off-pitch, but the same will not be the case with TrickPlay and the audio would seamlessly progress with the video without skipping any of its part. - In addition to all of the above, the new Silverlight 5 will be featuring wireless control of all the media contents by making use of remote controllers. With the use of such remote devices, it will be easier to handle the various media playback controls thereby providing more freedom while experiencing the premium media services. Silverlight 5 : Business Application Development The application development standard has been extended with more possibilities by bringing forth new and useful technologies and also reviving the existing methods to work better than what it was used to. From the UI improvements to advanced technical aspects, the Silverlight 5 scores high on all grounds to produce great next generation business delivered applications by putting in more creativity and resourceful touch to all the apps being produced with it. - The WPF feature of Silverlight is made more effective by introducing new standards of Databinding which is intended to improve the productivity standards of the Silverlight application developer. It brings in a lot of convenience in debugging the databinding components or expressions and hence making things work in a flawless manner. Some additional features related to databinding includes that of Ancestor RelativeSource, Implicit DataTemplates and Model View ViewModel (MVVM) support with DataContextChanged event and many other new features relating it. - It now comes with a refined text and printing service which facilitates better clarity of the text rendering and also many positive changes which are being applied to the layout pattern. New supports has been added to include OpenType font, multi-column text, linked-text containers and character leading support to name a few among the available features.This also includes some important printing aspects like that of Postscript Vector Printing API which allows to program our printing tasks in a user defined way and Pivot functionality for visualization concerns of informations. - The Graphics support is the key improvements being incorporated which now enables to utilize three dimensional graphics pattern using GPU acceleration. It can manage to provide some really cool visualizations being curved to provide media contents within the business apps with also the support for full HD contents at 1080p quality. - Silverlight 5 includes the support for 64-bit operating systems and relevant browsers and is also optimized to provide better performance. It can support the background thread for the networking which can reduce the latency of the network to a considerable extent. The Out-of-Browser functionality adds the support for utilizing various libraries and also the Win32 API. It also comes with testing support with VS 2010 which is mostly an automated procedure and has also enabled increased security aspects of all the Silverlight 5 developed applications by using the improved version of group policy support.

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  • Console keyboard input OOP

    - by Alexandre P. Levasseur
    I am trying to build a very simple console-based game with a focus on using OOP instead of procedural programming because I intend to build up on that code for more complex projects. I am wondering if there is a design pattern that nicely handles this use case: There is a Player class with a MakeMove() method interacting with the board game. The MakeMove() method has to somehow get the user input yet I do not want to code it into the Player class as this would reduce cohesion and augment coupling. I was thinking of maybe having some controller class handle the sequence of events and thus the calls to keyboard input. However, that controller class would need to be able to handle differently the subclasses of Player (e.g. the AI class does not require keyboard input). Thoughts ?

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  • The Presentation Secrets of Steve Jobs

    - by guybarrette
    A few years go, I got interested in presentation styles after reading Cliff Atkinson’s Beyond Bullet Points book.  At that time, it was obvious that the Microsoft presentation culture was kind of missing the point by having far too many bullet points. I recently picked up Carmine Gallo’s The Presentation Secrets of Steve Jobs.  I enjoyed this short read (238 pages) book full of presentation tips.  The best advise that I got from reading this book is that you must have an antagonist in your presentation.  This will help the audience visualize and understand the problem (antagonist) and the solution (what you present).  When presenting a technical topic, it is easy to forget to explain what problem is being solved by using this new technology/technique/pattern/API. This is a great read for anyone giving presentations, technical or not.     var addthis_pub="guybarrette";

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  • JIT compiler for C, C++, and the likes

    - by Ebrahim
    Is there any just-in-time compiler out there for compiled languages, such as C and C++? (The first names that come to mind are Clang and LLVM! But I don't think they currently support it.) Explanation: I think the software could benefit from runtime profiling feedback and aggressively optimized recompilation of hotspots at runtime, even for compiled-to-machine languages like C and C++. Profile-guided optimization does a similar job, but with the difference a JIT would be more flexible in different environments. In PGO you run your binary prior to releasing it. After you released it, it would use no environment/input feedbacks collected at runtime. So if the input pattern is changed, it is probe to performance penalty. But JIT works well even in that conditions. However I think it is controversial wether the JIT compiling performance benefit outweights its own overhead. Edit: Grammar

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  • Improving the state of the art in API documentation sites

    - by Daniel Cazzulino
    Go straight to the site if you want: http://nudoq.org. You can then come back and continue reading :) Compare some of the most popular NuGet packages API documentation sites: Json.NET EntityFramework NLog Autofac You see the pattern? Huge navigation tree views, static content with no comments/community content, very hard (if not impossible) to search/filter, etc. These are the product of automated tools that have been developed years ago, in a time where CHM help files were common and even expected from libraries. Nowadays, most of the top packages in NuGet.org don’t even provide an online documentation site at all: it’s such a hassle for such a crappy user experience in the end! Good news is that it doesn’t have to be that way. Introducing NuDoq A lot has changed since those early days of .NET. We now have NuGet packages and the awesome channel that is ...Read full article

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  • SQL SERVER – Example of Performance Tuning for Advanced Users with DB Optimizer

    - by Pinal Dave
    Performance tuning is such a subject that everyone wants to master it. In beginning everybody is at a novice level and spend lots of time learning how to master the art of performance tuning. However, as we progress further the tuning of the system keeps on getting very difficult. I have understood in my early career there should be no need of ego in the technology field. There are always better solutions and better ideas out there and we should not resist them. Instead of resisting the change and new wave I personally adopt it. Here is a similar example, as I personally progress to the master level of performance tuning, I face that it is getting harder to come up with optimal solutions. In such scenarios I rely on various tools to teach me how I can do things better. Once I learn about tools, I am often able to come up with better solutions when I face the similar situation next time. A few days ago I had received a query where the user wanted to tune it further to get the maximum out of the performance. I have re-written the similar query with the help of AdventureWorks sample database. SELECT * FROM HumanResources.Employee e INNER JOIN HumanResources.EmployeeDepartmentHistory edh ON e.BusinessEntityID = edh.BusinessEntityID INNER JOIN HumanResources.Shift s ON edh.ShiftID = s.ShiftID; User had similar query to above query was used in very critical report and wanted to get best out of the query. When I looked at the query – here were my initial thoughts Use only column in the select statements as much as you want in the application Let us look at the query pattern and data workload and find out the optimal index for it Before I give further solutions I was told by the user that they need all the columns from all the tables and creating index was not allowed in their system. He can only re-write queries or use hints to further tune this query. Now I was in the constraint box – I believe * was not a great idea but if they wanted all the columns, I believe we can’t do much besides using *. Additionally, if I cannot create a further index, I must come up with some creative way to write this query. I personally do not like to use hints in my application but there are cases when hints work out magically and gives optimal solutions. Finally, I decided to use Embarcadero’s DB Optimizer. It is a fantastic tool and very helpful when it is about performance tuning. I have previously explained how it works over here. First open DBOptimizer and open Tuning Job from File >> New >> Tuning Job. Once you open DBOptimizer Tuning Job follow the various steps indicates in the following diagram. Essentially we will take our original script and will paste that into Step 1: New SQL Text and right after that we will enable Step 2 for Generating Various cases, Step 3 for Detailed Analysis and Step 4 for Executing each generated case. Finally we will click on Analysis in Step 5 which will generate the report detailed analysis in the result pan. The detailed pan looks like. It generates various cases of T-SQL based on the original query. It applies various hints and available hints to the query and generate various execution plans of the query and displays them in the resultant. You can clearly notice that original query had a cost of 0.0841 and logical reads about 607 pages. Whereas various options which are just following it has different execution cost as well logical read. There are few cases where we have higher logical read and there are few cases where as we have very low logical read. If we pay attention the very next row to original query have Merge_Join_Query in description and have lowest execution cost value of 0.044 and have lowest Logical Reads of 29. This row contains the query which is the most optimal re-write of the original query. Let us double click over it. Here is the query: SELECT * FROM HumanResources.Employee e INNER JOIN HumanResources.EmployeeDepartmentHistory edh ON e.BusinessEntityID = edh.BusinessEntityID INNER JOIN HumanResources.Shift s ON edh.ShiftID = s.ShiftID OPTION (MERGE JOIN) If you notice above query have additional hint of Merge Join. With the help of this Merge Join query hint this query is now performing much better than before. The entire process takes less than 60 seconds. Please note that it the join hint Merge Join was optimal for this query but it is not necessary that the same hint will be helpful in all the queries. Additionally, if the workload or data pattern changes the query hint of merge join may be no more optimal join. In that case, we will have to redo the entire exercise once again. This is the reason I do not like to use hints in my queries and I discourage all of my users to use the same. However, if you look at this example, this is a great case where hints are optimizing the performance of the query. It is humanly not possible to test out various query hints and index options with the query to figure out which is the most optimal solution. Sometimes, we need to depend on the efficiency tools like DB Optimizer to guide us the way and select the best option from the suggestion provided. Let me know what you think of this article as well your experience with DB Optimizer. Please leave a comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Delegates and Events in C#

    - by hakanbilge
    Events and their underlying mechanism "Delegates" are very powerful tools of a developer and Event Driven Programming is one of the main Programming Paradigms. Its wiki definition is "event-driven programming or event-based programming is a programming paradigm in which the flow of the program is determined by events?i.e., sensor outputs or user actions (mouse clicks, key presses) or messages from other programs or threads." That means, your program can go its own way sequentially and in the case of anything that requires attention is done (when an event fires) by somebody or something, you can response it by using that event's controller method (this mechanism is like interrupt driven programming in embedded systems). There are many real world scenarios for events, for example, ASP.NET uses events to catch a click on a button or in your app, controller has notice of a change in UI by handling events exposed by view (in MVC pattern). Delegates in C# C# delegates correspond to function pointers in  [read more....]

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  • Dual Control / Four Eyes Principle

    - by Ralf
    I have the requirement to implement some kind of Dual Control or Four-Eyes-Principle, meaning that every change of an object done by user A has to be checked by user B. A trivial example would be a publishing system where an author writes an article and another has to proofread it before it is published. I am a little bit surprised that you find nearly nothing about it on the net. No patterns, no libraries (besides cibet), no workflow solutions etc. Is this requirement really so uncommon? Or am I searching for the wrong terms? I am not looking for a specific solution. More for a pattern or best practice approach.

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  • Primary domain in vps in vps has been deactivated

    - by manix
    This is my scenario: I have a vps with two domains (example1.com, example2.com). When I started with this vps I set example1.com as primary domain and the nameserver were configured with the pattern ns1.example.com, ns2.example1.com. The domains were brought in name.com. Across the time, I usually only work whit the domain example2.com, for that reason I stopped to pay example1.com anual registration and just keep the example2.com. But, today my vps is unreacheable because the main domain was deactivated last ago 23th. I never imagined that it could affect my server. So, I am so worried because I don't know if rebuild the vps is the solution here because I could lost my data. Can you take me to the right direction in order to recover my vps?

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  • Dissecting ASP.NET Routing

    The ASP.NET Routing framework allows developers to decouple the URL of a resource from the physical file on the web server. Specifically, the developer defines <i>routing rules</i>, which map URL patterns to a class or ASP.NET page that generates the content. For instance, you could create a URL pattern of the form <code>Categories/<i>CategoryName</i></code> and map it to the ASP.NET page <code>ShowCategoryDetails.aspx</code>; the <code>ShowCategoryDetails.aspx</code> page would display details about the category <i>CategoryName</i>. With such a mapping, users could view category about the Beverages category by visiting <code>www.yoursite.com/Categories/Beverages</code>. In short, ASP.NET Routing allows

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  • Workarounds for supporting MVVM in the Silverlight TreeView Control

    - by cibrax
    MVVM (Model-View-ViewModel) is the pattern that you will typically choose for building testable user interfaces either in WPF or Silverlight. This pattern basically relies on the data binding support in those two technologies for mapping an existing model class (the view model) to the different parts of the UI or view. Unfortunately, MVVM was not threated as first citizen for some of controls released out of the box in the Silverlight runtime or the Silverlight toolkit. That means that using data binding for implementing MVVM is not always something trivial and usually requires some customization in the existing controls. In ran into different problems myself trying to fully support data binding in controls like the tree view or the context menu or things like drag & drop.  For that reason, I decided to write this post to show how the tree view control or the tree view items can be customized to support data binding in many of its properties. In first place, you will typically use a tree view for showing hierarchical data so the view model somehow must reflect that hierarchy. An easy way to implement hierarchy in a model is to use a base item element like this one, public abstract class TreeItemModel { public abstract IEnumerable<TreeItemModel> Children; } You can later derive your concrete model classes from that base class. For example, public class CustomerModel { public string FullName { get; set; } public string Address { get; set; } public IEnumerable<OrderModel> Orders { get; set; } }   public class CustomerTreeItemModel : TreeItemModel { public CustomerTreeItemModel(CustomerModel customer) { }   public override IEnumerable<TreeItemModel> Children { get { // Return orders } } } The Children property in the CustomerTreeItem model implementation can return for instance an ObservableCollection<TreeItemModel> with the orders, so the tree view will automatically subscribe to all the changes in the collection. You can bind this model to the tree view control in the UI by using a Hierarchical data template. <e:TreeView x:Name="TreeView" ItemsSource="{Binding Customers}"> <e:TreeView.ItemTemplate> <sdk:HierarchicalDataTemplate ItemsSource="{Binding Children}"> <!-- TEMPLATE --> </sdk:HierarchicalDataTemplate> </e:TreeView.ItemTemplate> </e:TreeView> An interesting behavior with the Children property and the Hierarchical data template is that the Children property is only invoked before the expansion, so you can use lazy load at this point (The tree view control will not expand the whole tree in the first expansion). The problem with using MVVM in this control is that you can not bind properties in model with specific properties of the TreeView item such as IsSelected or IsExpanded. Here is where you need to customize the existing tree view control to support data binding in tree items. public class CustomTreeView : TreeView { public CustomTreeView() { }   protected override DependencyObject GetContainerForItemOverride() { CustomTreeViewItem tvi = new CustomTreeViewItem(); Binding expandedBinding = new Binding("IsExpanded"); expandedBinding.Mode = BindingMode.TwoWay; tvi.SetBinding(CustomTreeViewItem.IsExpandedProperty, expandedBinding); Binding selectedBinding = new Binding("IsSelected"); selectedBinding.Mode = BindingMode.TwoWay; tvi.SetBinding(CustomTreeViewItem.IsSelectedProperty, selectedBinding); return tvi; } }   public class CustomTreeViewItem : TreeViewItem { public CustomTreeViewItem() { }   protected override DependencyObject GetContainerForItemOverride() { CustomTreeViewItem tvi = new CustomTreeViewItem(); Binding expandedBinding = new Binding("IsExpanded"); expandedBinding.Mode = BindingMode.TwoWay; tvi.SetBinding(CustomTreeViewItem.IsExpandedProperty, expandedBinding); Binding selectedBinding = new Binding("IsSelected"); selectedBinding.Mode = BindingMode.TwoWay; tvi.SetBinding(CustomTreeViewItem.IsSelectedProperty, selectedBinding); return tvi; } } You basically need to derive the TreeView and TreeViewItem controls to manually add a binding for the properties you need. In the example above, I am adding a binding for the “IsExpanded” and “IsSelected” properties in the items. The model for the tree items now needs to be extended to support those properties as well, public abstract class TreeItemModel : INotifyPropertyChanged { bool isExpanded = false; bool isSelected = false;   public abstract IEnumerable<TreeItemModel> Children { get; }   public bool IsExpanded { get { return isExpanded; } set { isExpanded = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("IsExpanded")); } }   public bool IsSelected { get { return isSelected; } set { isSelected = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("IsSelected")); } }   public event PropertyChangedEventHandler PropertyChanged; } However, as soon as you use this custom tree view control, you lose all the automatic styles from the built-in toolkit themes because they are tied to the control type (TreeView in this case).  The only ugly workaround I found so far for this problem is to copy the styles from the Toolkit source code and reuse them in the application.

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  • Are There Any Examples of Uncle Bob's High-Falutin' Architecture?

    - by Jordan
    I just finished watching this presentation by Uncle Bob (as well as his "Architecture" section of his "Clean Code" videos), but I'm left wondering: Are there any examples out there of applications that implement this Entity-Boundary-Interactor (or Entity-Boundary-Controller) structure? At one point I downloaded the source code to FitNesse (the acceptance testing project he mentions often as an example of not only high test coverage but good architecture, since they were able to defer the decision to not use a database until the very end), and based on a quick glance of it it appears even this project doesn't seem to fit this pattern. Are there any nontrivial examples of this architecture out in the wild, or should I not bother even looking into it and chalk it up as "it would be great if you could get there, but nobody really does"?

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  • How to make Rect of irregular shape sprite?

    - by Anil gupta
    I used masking for breaking an image as the below mention pattern now its breaking in different pieces but now i have one issue to make the Rect of each pieces, i need to drag the broken pieces and to adjust at correct position so that i can make again actual images. To drag and put at right positing i need to make Rect but i am not getting idea how to make Rect of this irregular shape, I will be very thankful to you, any idea or code to make rect . My previous Question is: How do I break an image into 6 or 8 pieces of different shapes? Thanks.

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  • CLR via C# 3rd Edition is out

    - by Abhijeet Patel
    Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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  • F# for the C# Programmer

    - by mbcrump
    Are you a C# Programmer and can’t make it past a day without seeing or hearing someone mention F#?  Today, I’m going to walk you through your first F# application and give you a brief introduction to the language. Sit back this will only take about 20 minutes. Introduction Microsoft's F# programming language is a functional language for the .NET framework that was originally developed at Microsoft Research Cambridge by Don Syme. In October 2007, the senior vice president of the developer division at Microsoft announced that F# was being officially productized to become a fully supported .NET language and professional developers were hired to create a team of around ten people to build the product version. In September 2008, Microsoft released the first Community Technology Preview (CTP), an official beta release, of the F# distribution . In December 2008, Microsoft announced that the success of this CTP had encouraged them to escalate F# and it is now will now be shipped as one of the core languages in Visual Studio 2010 , alongside C++, C# 4.0 and VB. The F# programming language incorporates many state-of-the-art features from programming language research and ossifies them in an industrial strength implementation that promises to revolutionize interactive, parallel and concurrent programming. Advantages of F# F# is the world's first language to combine all of the following features: Type inference: types are inferred by the compiler and generic definitions are created automatically. Algebraic data types: a succinct way to represent trees. Pattern matching: a comprehensible and efficient way to dissect data structures. Active patterns: pattern matching over foreign data structures. Interactive sessions: as easy to use as Python and Mathematica. High performance JIT compilation to native code: as fast as C#. Rich data structures: lists and arrays built into the language with syntactic support. Functional programming: first-class functions and tail calls. Expressive static type system: finds bugs during compilation and provides machine-verified documentation. Sequence expressions: interrogate huge data sets efficiently. Asynchronous workflows: syntactic support for monadic style concurrent programming with cancellations. Industrial-strength IDE support: multithreaded debugging, and graphical throwback of inferred types and documentation. Commerce friendly design and a viable commercial market. Lets try a short program in C# then F# to understand the differences. Using C#: Create a variable and output the value to the console window: Sample Program. using System;   namespace ConsoleApplication9 {     class Program     {         static void Main(string[] args)         {             var a = 2;             Console.WriteLine(a);             Console.ReadLine();         }     } } A breeze right? 14 Lines of code. We could have condensed it a bit by removing the “using” statment and tossing the namespace. But this is the typical C# program. Using F#: Create a variable and output the value to the console window: To start, open Visual Studio 2010 or Visual Studio 2008. Note: If using VS2008, then please download the SDK first before getting started. If you are using VS2010 then you are already setup and ready to go. So, click File-> New Project –> Other Languages –> Visual F# –> Windows –> F# Application. You will get the screen below. Go ahead and enter a name and click OK. Now, you will notice that the Solution Explorer contains the following: Double click the Program.fs and enter the following information. Hit F5 and it should run successfully. Sample Program. open System let a = 2        Console.WriteLine a As Shown below: Hmm, what? F# did the same thing in 3 lines of code. Show me the interactive evaluation that I keep hearing about. The F# development environment for Visual Studio 2010 provides two different modes of execution for F# code: Batch compilation to a .NET executable or DLL. (This was accomplished above). Interactive evaluation. (Demo is below) The interactive session provides a > prompt, requires a double semicolon ;; identifier at the end of a code snippet to force evaluation, and returns the names (if any) and types of resulting definitions and values. To access the F# prompt, in VS2010 Goto View –> Other Window then F# Interactive. Once you have the interactive window type in the following expression: 2+3;; as shown in the screenshot below: I hope this guide helps you get started with the language, please check out the following books for further information. F# Books for further reading   Foundations of F# Author: Robert Pickering An introduction to functional programming with F#. Including many samples, this book walks through the features of the F# language and libraries, and covers many of the .NET Framework features which can be leveraged with F#.       Functional Programming for the Real World: With Examples in F# and C# Authors: Tomas Petricek and Jon Skeet An introduction to functional programming for existing C# developers written by Tomas Petricek and Jon Skeet. This book explains the core principles using both C# and F#, shows how to use functional ideas when designing .NET applications and presents practical examples such as design of domain specific language, development of multi-core applications and programming of reactive applications.

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