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  • Event Handlers Not Getting Called? - wxWidgets & C++

    - by Alex
    Hello all, I'm working on a program for my C++ programming class, using wxWidgets. I'm having a huge problem in that my event handlers (I assume) are not getting called, because when I click on the button to trigger the event, nothing happens. My question is: Can you help me find the problem and explain why they would not be getting called? The event handlers OnAbout and OnQuit are working, just not OnCompute or OnClear. I'm really frustrated as I can't figure this out. Thanks a bunch in advance! #include "wx/wx.h" #include "time.h" #include <string> using std::string; // create object of Time class Time first; class App: public wxApp { virtual bool OnInit(); }; class MainPanel : public wxPanel { public: // Constructor for panel class // Constructs my panel class // Params - wxWindow pointer // no return type // pre-conditions: none // post-conditions: none MainPanel(wxWindow* parent); // OnCompute is the event handler for the Compute button // params - none // preconditions - none // postconditions - tasks will have been carried otu successfully // returns void void OnCompute(wxCommandEvent& WXUNUSED(event)); // OnClear is the event handler for the Clear button // params - none // preconditions - none // postconditions - all text areas will be cleared of data // returns void void OnClear(wxCommandEvent& WXUNUSED(event)); // Destructor for panel class // params none // preconditions - none // postconditions - none // no return type ~MainPanel( ); private: wxStaticText *startLabel; wxStaticText *endLabel; wxStaticText *pCLabel; wxStaticText *newEndLabel; wxTextCtrl *start; wxTextCtrl *end; wxTextCtrl *pC; wxTextCtrl *newEnd; wxButton *compute; wxButton *clear; DECLARE_EVENT_TABLE() }; class MainFrame: public wxFrame { private: wxPanel *mainPanel; public: MainFrame(const wxString& title, const wxPoint& pos, const wxSize& size); void OnQuit(wxCommandEvent& event); void OnAbout(wxCommandEvent& event); ~MainFrame(); DECLARE_EVENT_TABLE() }; enum { ID_Quit = 1, ID_About, BUTTON_COMPUTE = 100, BUTTON_CLEAR = 200 }; IMPLEMENT_APP(App) BEGIN_EVENT_TABLE(MainFrame, wxFrame) EVT_MENU(ID_Quit, MainFrame::OnQuit) EVT_MENU(ID_About, MainFrame::OnAbout) END_EVENT_TABLE() BEGIN_EVENT_TABLE(MainPanel, wxPanel) EVT_MENU(BUTTON_COMPUTE, MainPanel::OnCompute) EVT_MENU(BUTTON_CLEAR, MainPanel::OnClear) END_EVENT_TABLE() bool App::OnInit() { MainFrame *frame = new MainFrame( _("Good Guys Delivery Time Calculator"), wxPoint(50, 50), wxSize(450,340) ); frame->Show(true); SetTopWindow(frame); return true; } MainPanel::MainPanel(wxWindow* parent) : wxPanel(parent) { startLabel = new wxStaticText(this, -1, "Start Time:", wxPoint(75, 35)); start = new wxTextCtrl(this, -1, "", wxPoint(135, 35), wxSize(40, 21)); endLabel = new wxStaticText(this, -1, "End Time:", wxPoint(200, 35)); end = new wxTextCtrl(this, -1, "", wxPoint(260, 35), wxSize(40, 21)); pCLabel = new wxStaticText(this, -1, "Percent Change:", wxPoint(170, 85)); pC = new wxTextCtrl(this, -1, "", wxPoint(260, 85), wxSize(40, 21)); newEndLabel = new wxStaticText(this, -1, "New End Time:", wxPoint(180, 130)); newEnd = new wxTextCtrl(this, -1, "", wxPoint(260, 130), wxSize(40, 21)); compute = new wxButton(this, BUTTON_COMPUTE, "Compute", wxPoint(135, 185), wxSize(75, 35)); clear = new wxButton(this, BUTTON_CLEAR, "Clear", wxPoint(230, 185), wxSize(75, 35)); } MainPanel::~MainPanel() {} MainFrame::MainFrame(const wxString& title, const wxPoint& pos, const wxSize& size) : wxFrame( NULL, -1, title, pos, size ) { mainPanel = new MainPanel(this); wxMenu *menuFile = new wxMenu; menuFile->Append( ID_About, _("&About...") ); menuFile->AppendSeparator(); menuFile->Append( ID_Quit, _("E&xit") ); wxMenuBar *menuBar = new wxMenuBar; menuBar->Append( menuFile, _("&File") ); SetMenuBar( menuBar ); CreateStatusBar(); SetStatusText( _("Hi") ); } MainFrame::~MainFrame() {} void MainFrame::OnQuit(wxCommandEvent& WXUNUSED(event)) { Close(TRUE); } void MainFrame::OnAbout(wxCommandEvent& WXUNUSED(event)) { wxMessageBox( _("Alex Olson\nProject 11"), _("About"), wxOK | wxICON_INFORMATION, this); } void MainPanel::OnCompute(wxCommandEvent& WXUNUSED(event)) { int startT; int endT; int newEndT; double tD; wxString startTString = start->GetValue(); wxString endTString = end->GetValue(); startT = wxAtoi(startTString); endT = wxAtoi(endTString); pC->GetValue().ToDouble(&tD); first.SetStartTime(startT); first.SetEndTime(endT); first.SetTimeDiff(tD); try { first.ValidateData(); newEndT = first.ComputeEndTime(); *newEnd << newEndT; } catch (BaseException& e) { wxMessageBox(_(e.GetMessage()), _("Something Went Wrong!"), wxOK | wxICON_INFORMATION, this); } } void MainPanel::OnClear(wxCommandEvent& WXUNUSED(event)) { start->Clear(); end->Clear(); pC->Clear(); newEnd->Clear(); }

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  • Why is design by contract considered an alternative to the pseudo programming process?

    - by zoopp
    Right now I'm reading Code Complete by Steve McConnell and in chapter 9 he talks about the Pseudo Programming Process (PPP). From what I've understood, the PPP is a way of programming in which the programmer first writes the pseudo code for the routine he's working on, then refines it up to the point where pretty much each pseudo code line can be implemented in 1-3 lines of code, then writes the code in the designated programming language and finally the pseudo code is saved as comments for the purpose of documenting the routine. In chapter 9.4 the author mentions alternatives to the PPP, one of which is 'design by contract'. In design by contract you basically assert preconditions and postconditions of each routine. Now why would that be considered an alternative? To me it seems obvious that I should use both techniques at the same time and not chose one over the other.

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  • Programming language features that help to catch bugs early

    - by Christian Neumanns
    Do you know any programming language features that help to detect bugs early in the software development process - ideally at compile-time or else as early as possible at run-time? Examples of well-known and effective bug-reducing features are: Static typing and generic types: type incompatibility errors are detected by the compiler Design by Contract (TM), also called Contract Programming: invalid values are quickly detected at runtime (through preconditions, postconditions and class invariants) Unit testing I ask this question in the context of improving an object-oriented programming language (called Obix) which has been designed from the ground up to 'make it easy to quickly write reliable code'. Besides the features mentioned above this language also incorporates other Fail-fast features such as: Objects are immutable by default Void (null) values are not allowed by default The aim is to add more Fail-fast concepts to the language. If you know other features which help to write less error-prone code then please let us know. Thank you.

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  • How to verify the Liskov substitution principle in an inheritance hierarchy?

    - by Songo
    Inspired by this answer: Liskov Substitution Principle requires that Preconditions cannot be strengthened in a subtype. Postconditions cannot be weakened in a subtype. Invariants of the supertype must be preserved in a subtype. History constraint (the "history rule"). Objects are regarded as being modifiable only through their methods (encapsulation). Since subtypes may introduce methods that are not present in the supertype, the introduction of these methods may allow state changes in the subtype that are not permissible in the supertype. The history constraint prohibits this. I was hoping if someone would post a class hierarchy that violates these 4 points and how to solve them accordingly. I'm looking for an elaborate explanation for educational purposes on how to identify each of the 4 points in the hierarchy and the best way to fix it. Note: I was hoping to post a code sample for people to work on, but the question itself is about how to identify the faulty hierarchies :)

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  • Essential topics to be discussed in Linux 101

    - by zengr
    Hi, We are organizing a Linux 101 Workshop for undergrad and grad students. Can you share some ideas/topics that are must for people who are just starting with Linux. Preconditions: No knowledge of Linux OS, philosophy and technical aspects (kernel, shell, commands) Post conditions: A basic crash course of Linux which will give them a good start and answer some basic questions asked on it.

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  • Catch Multiple Custom Exceptions? - C++

    - by Alex
    Hi all, I'm a student in my first C++ programming class, and I'm working on a project where we have to create multiple custom exception classes, and then in one of our event handlers, use a try/catch block to handle them appropriately. My question is: How do I catch my multiple custom exceptions in my try/catch block? GetMessage() is a custom method in my exception classes that returns the exception explanation as a std::string. Below I've included all the relevant code from my project. Thanks for your help! try/catch block // This is in one of my event handlers, newEnd is a wxTextCtrl try { first.ValidateData(); newEndT = first.ComputeEndTime(); *newEnd << newEndT; } catch (// don't know what do to here) { wxMessageBox(_(e.GetMessage()), _("Something Went Wrong!"), wxOK | wxICON_INFORMATION, this);; } ValidateData() Method void Time::ValidateData() { int startHours, startMins, endHours, endMins; startHours = startTime / MINUTES_TO_HOURS; startMins = startTime % MINUTES_TO_HOURS; endHours = endTime / MINUTES_TO_HOURS; endMins = endTime % MINUTES_TO_HOURS; if (!(startHours <= HOURS_MAX && startHours >= HOURS_MIN)) throw new HourOutOfRangeException("Beginning Time Hour Out of Range!"); if (!(endHours <= HOURS_MAX && endHours >= HOURS_MIN)) throw new HourOutOfRangeException("Ending Time Hour Out of Range!"); if (!(startMins <= MINUTE_MAX && startMins >= MINUTE_MIN)) throw new MinuteOutOfRangeException("Starting Time Minute Out of Range!"); if (!(endMins <= MINUTE_MAX && endMins >= MINUTE_MIN)) throw new MinuteOutOfRangeException("Ending Time Minute Out of Range!"); if(!(timeDifference <= P_MAX && timeDifference >= P_MIN)) throw new PercentageOutOfRangeException("Percentage Change Out of Range!"); if (!(startTime < endTime)) throw new StartEndException("Start Time Cannot Be Less Than End Time!"); } Just one of my custom exception classes, the others have the same structure as this one class HourOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type HourOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~HourOutOfRangeException() {} private: string message; };

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  • When should I opt for test driven development?

    - by VJ
    My question is same as the title. I have not done Test driven development yet,I have performed unit testing and I am aware of testing in general but I hear it is much advantageous to follow TDD?. So should I opt for it everytime or are there some preconditions... i just need to know some basic or important requirements when i should opt for TDD. Sorry if this question is too trivial.

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  • Android Test testPreconditions

    - by user1184113
    In Android developers I've seen that testPreconditions() method is supposed to be launch before all tests. But in my app test, it's acting like a normal test. It does not run before all tests. Is there something wrong ? Here is the description about testPreconditions() from android developer : "A preconditions test checks the initial application conditions prior to executing other tests. It's similar to setUp(), but with less overhead, since it only runs once."

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  • Error attempting to log into Redmine through IIS 7.5 Reverse Proxy

    - by dneaster3
    I am trying to set up Redmine as a subdirectory of our department's intranet site, and also to rebrand it as "Workflow" using IIS's URL Rewrite extension. I have it "working" in that it will serve the page with all the correct rewrites in both the URL and the HTML code. However, when I try to submit a form (including logging in to redmine), IIS gives me one of the the following errors: Your browser sent a request that this server could not understand. or The specified CGI application encountered an error and the server terminated the process. Here's the setup: Redmine installed on a local Windows XP machine using the Bitnami all-in-one installer, which includes: Apache 2 Ruby-on-Rails MySQL Redmine Thin Redmine runs locally at http:/localhost/redmine Redmine runs over the intranet http:/146.18.236.xxx/redmine Windows Server + IIS 7.5 serving up an ASP.NET intranet web application mydept.mycompany.com IIS Extensions Url Rewrite and AAR installed Reverse proxy settings for IIS (shown below) to serve Redmine at mydept.mycompany.com/workflow <rewrite> <rules> <rule name="Route requests for workflow to redmine server" stopProcessing="true"> <match url="^workflow/?(.*)" /> <conditions> <add input="{CACHE_URL}" pattern="^(https?)://" /> </conditions> <action type="Rewrite" url="{C:1}://146.18.236.xxx/redmine/{R:1}" logRewrittenUrl="true" /> <serverVariables> <set name="HTTP_ACCEPT_ENCODING" value="" /> <set name="ORIGINAL_HOST" value="{HTTP_HOST}" /> </serverVariables> </rule> </rules> <outboundRules rewriteBeforeCache="true"> <clear /> <preConditions> <preCondition name="isHTML" logicalGrouping="MatchAny"> <add input="{RESPONSE_CONTENT_TYPE}" pattern="^text/html" /> <add input="{RESPONSE_CONTENT_TYPE}" pattern="^text/plain" /> <add input="{RESPONSE_CONTENT_TYPE}" pattern="^application/.*xml" /> </preCondition> <preCondition name="isRedirection"> <add input="{RESPONSE_STATUS}" pattern="3\d\d" /> </preCondition> </preConditions> <rule name="Rewrite outbound relative URLs in tags" preCondition="isHTML"> <match filterByTags="A, Area, Base, Form, Frame, Head, IFrame, Img, Input, Link, Script" pattern="^/redmine/(.*)" /> <action type="Rewrite" value="/workflow/{R:1}" /> </rule> <rule name="Rewrite outbound absolute URLs in tags" preCondition="isHTML"> <match filterByTags="A, Area, Base, Form, Frame, Head, IFrame, Img, Input, Link, Script" pattern="^(https?)://146.18.236.xxx/redmine/(.*)" /> <action type="Rewrite" value="{R:1}://mydept.mycompany.com/workflow/{R:2}" /> </rule> <rule name="Rewrite tags with hypenated properties missed by IIS bug" preCondition="isHTML"> <!-- http://forums.iis.net/t/1200916.aspx --> <match filterByTags="None" customTags="" pattern="(\baction=&quot;|\bsrc=&quot;|\bhref=&quot;)/redmine/(.*?)(&quot;)" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="true" /> <action type="Rewrite" value="{R:1}/workflow/{R:2}{R:3}" /> </rule> <rule name="Rewrite Location Header" preCondition="isRedirection"> <match serverVariable="RESPONSE_LOCATION" pattern="^http://[^/]+/(.*)" /> <conditions> <add input="{ORIGINAL_URL}" pattern=".+" /> <add input="{URL}" pattern="^/(workflow|redmine)/.*" /> </conditions> <action type="Rewrite" value="http://{ORIGINAL_URL}/{C:1}/{R:1}" /> </rule> </outboundRules> </rewrite> <urlCompression dynamicCompressionBeforeCache="false" /> Any help that you can provide would be appreciated. I get the impression that I'm close adn that it is just one little setting here or there, but I can't seem to make it work.

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  • Code review “on a napkin” — could it be useful?

    - by gaRex
    Preconditions Team uses DVCS IDE supports comments parsing (like TODO and etc.) Tools like CodeCollaborator are expensive for budget Tools like gerrit are too complex for install or not usable Workflow Author publishes somewhere on central repo feature branch Reviewer fetch it and start review In case of some question/issue reviewer create comment with special label, like "BLA". Such label MUST not be in production code -- only on review stage: $somevar = 123; // BLA Why do echo this here? echo $somevar; When reviewer finish post comments -- it just commits with stupid message "comments" and pushes back Author pulls feature branch back and answer comments in similar way or improve code and push it back When "BLA" comments have gone we can think, that review has successfully finished. Author interactively rebases feature branch, stashes it to remove those "comment" commits and now is ready to merge feature to develop or make any action that usualy could be after successful internal review IDE support I know, that custom comment tags are possible in eclipse & netbeans. Sure it also should be in blablaStorm family. So my specific questions are Do you think this methodology is viable? Do you know something similar? What can be improved in it? ps: migrated from http://stackoverflow.com/questions/12692695/code-review-on-a-napkin-could-it-be-useful

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  • Do Repeat Yourself in Unit Tests

    - by João Angelo
    Don’t get me wrong I’m a big supporter of the DRY (Don’t Repeat Yourself) Principle except however when it comes to unit tests. Why? Well, in my opinion a unit test should be a self-contained group of actions with the intent to test a very specific piece of code and should not depend on externals shared with other unit tests. In a typical unit test we can divide its code in two major groups: Preparation of preconditions for the code under test; Invocation of the code under test. It’s in the first group that you are tempted to refactor common code in several unit tests into helper methods that can then be called in each one of them. Another way to not duplicate code is to use the built-in infrastructure of some unit test frameworks such as SetUp/TearDown methods that automatically run before and after each unit test. I must admit that in the past I was guilty of both charges but what at first seemed a good idea since I was removing code duplication turnout to offer no added value and even complicate the process when a given test fails. We love unit tests because of their rapid feedback when something goes wrong. However, this feedback requires most of the times reading the code for the failed test. Given this, what do you prefer? To read a single method or wander through several methods like SetUp/TearDown and private common methods. I say it again, do repeat yourself in unit tests. It may feel wrong at first but I bet you won’t regret it later.

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  • Is a code review which uses only code comments a good idea?

    - by gaRex
    Preconditions Team uses DVCS IDE supports comments parsing (like TODO and etc.) Tools like CodeCollaborator are expensive for budget Tools like gerrit are too complex for install or not usable Workflow Author publishes somewhere on central repo feature branch Reviewer fetch it and start review In case of some question/issue reviewer create comment with special label, like "REV". Such label MUST not be in production code -- only on review stage: $somevar = 123; // REV Why do echo this here? echo $somevar; When reviewer finish post comments -- it just commits with stupid message "comments" and pushes back Author pulls feature branch back and answer comments in similar way or improve code and push it back When "REV" comments have gone we can think, that review has successfully finished. Author interactively rebases feature branch, squashes it to remove those "comment" commits and now is ready to merge feature to develop or make any action that usualy could be after successful internal review IDE support I know, that custom comment tags are possible in eclipse & netbeans. Sure it also should be in blablaStorm family. Questions Do you think this methodology is viable? Do you know something similar? What can be improved in it?

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  • MVVM Light V4b1 for Windows 8 Consumer Preview (with installer)

    - by Laurent Bugnion
    I just pushed the following to Codeplex: A new MVVM Light project template for Windows 8 Consumer Preview. This template appears in the File, New Project dialog and allows you to create a Metro style app already wired with MVVM Light. An updated Windows 8 installer for MVVM Light. Preconditions: This installs MVVM Light for Windows 8 only. You can install it side-by-side with the standard MVVM Light for Silverlight, WPF and Windows Phone. Where do I get it? You can download the MSI from: http://mvvmlight.codeplex.com/releases/view/85317 What does it do? The installer installs the Windows 8 version of the MVVM Light DLLs, as well as a new project template for an MVVM Light Metro style app, and code snippets. What is missing? Since Windows 8 Developer Preview, I worked on porting the DispatcherHelper class, and it works now. However the EventToCommand behavior is still not available on Windows 8 (because behaviors are not supported on Windows 8 for the moment). Known issues Some testers reported issues with the code snippets installation. Code snippets should appear when you type “mvvm” in your C# code, there is a list of mvvm-prefixed snippets (such as mvvminpc, etc). If you do not see these snippets, please stay tuned, I am working on fixing this issue.   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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  • Apply bone tranforms when importing FBX in XNA

    - by hichaeretaqua
    Preconditions: I have some models, that does only contain some meshes and one texture. There is no animation within the model. An example: a model of a table. I want to draw the Model with a custom effect, so I have to swap the effect after loading the model. In order to draw them correctly, I have to apply the bone transformation manually on each draw for each mesh and effect as can be seen here. So there are two questions: Is there a option during import that allows my to apply the bone transformation on all vertices, so that during draw call I should not have to do this? Is there a option during import that merges all vertices into a Vertex- and IndexBuffer, that allows me to draw the whole model with just one call? I'm pretty sure that the build-in "Autodesk FBX - XNA Framework" does not support this features, but maybe there is an other imported available or an other possibility I missed. The aim is to speed up rendering a little bit especially by using instancing. So having one VertexBuffer to draw at one time would be pretty nice.

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  • Domain Model and Contracts

    - by devoured elysium
    I am modelling a DVD Rental Store: A Client gives its clientNumber to the System. The System checks whenever the given clientNumber is valid. The Client gives the name of the DVD he wants to rent. ... n. ...I will later have to form an association between a new instance of "RentDVD" class concept to the current Client c. My Domain Model is something like: I've made the Contract for the first and second operations as: Preconditions: none Postconditions: there exists a Client c such that c.clientNumber = clientNumber. Now, I don't know if I should form an association between this Client c and the DVDStore(that I intend to use as front-end). If I don't make the association, how will I later be able to "reference" this same Client? Should I be making an association between Client and a different concept? Thanks

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  • Code Contracts: validating arrays and collections

    - by DigiMortal
    Validating collections before using them is very common task when we use built-in generic types for our collections. In this posting I will show you how to validate collections using code contracts. It is cool how much awful looking code you can avoid using code contracts. Failing code Let’s suppose we have method that calculates sum of all invoices in collection. We have class Invoice and one of properties it has is Sum. I don’t introduce here any complex calculations on invoices because we have another problem to solve in this topic. Here is our code. public static decimal CalculateTotal(IList<Invoice> invoices) {     var sum = invoices.Sum(p => p.Sum);     return sum; } This method is very simple but it fails when invoices list contains at least one null. Of course, we can test if invoice is null but having nulls in lists like this is not good idea – it opens green way for different coding bugs in system. Our goal is to react to bugs ASAP at the nearest place they occur. There is one more way how to make our method fail. It happens when invoices is null. I thing it is also one common bugs during development and it even happens in production environments under some conditions that are usually hardly met. Now let’s protect our little calculation method with code contracts. We need two contracts: invoices cannot be null invoices cannot contain any nulls Our first contract is easy but how to write the second one? Solution: Contract.ForAll Preconditions in code are checked using Contract.Ensures method. This method takes boolean value as argument that sais if contract holds or not. There is also method Contract.ForAll that takes collection and predicate that must hold for that collection. Nice thing is ForAll returns boolean. So, we have very simple solution. public static decimal CalculateTotal(IList<Invoice> invoices) {     Contract.Requires(invoices != null);     Contract.Requires(Contract.ForAll<Invoice>(invoices, p => p != null));       var sum = invoices.Sum(p => p.Sum);     return sum; } And here are some lines of code you can use to test the contracts quickly. var invoices = new List<Invoice>(); invoices.Add(new Invoice()); invoices.Add(null); invoices.Add(new Invoice()); //CalculateTotal(null); CalculateTotal(invoices); If your code is covered with unit tests then I suggest you to write tests to check that these contracts hold for every code run. Conclusion Although it seemed at first place that checking all elements in collection may end up with for-loops that does not look so nice we were able to solve our problem nicely. ForAll method of contract class offered us simple mechanism to check collections and it does it smoothly the code-contracts-way. P.S. I suggest you also read devlicio.us blog posting Validating Collections with Code Contracts by Derik Whittaker.

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  • Pseudocode help

    - by vatsag
    Hello All I've been banging my head over few hours for realising this particular logic My task is to have a masterlist ListM elements of which shall be list(again) in the form of ListA(type A) and ListB(type B) and ListC(type C)(some generic type). Also the lists A and ListB can contain elements of type C(some generic type). Coming to the preconditions 1. ListA can contain only 50 elements of type 'A', rest of the elements can be of generic type C 2. ListB can contain only 50 elements of type 'B', rest of the elements can be of generic type C 3. Also the lists(ListA or ListB) can take at max of 100 elements. 4. ListC can contain elements of generic type C and can take max of 100 elements For ex: Now, If i have 200 elements of type A and 200 elements of type B and 600 elements of type C then i should be able to get 4 Lists(50 elements in each list) of type...ListA (because each ListA can contain at max of 50 elements of type A only, rem 50 is typeC) 4 Lists(50 elements in each list) of type...ListB (because each ListA can contain at max of 50 elements of type B only, rem 50 is typeC) 2 Lists(50 elements in each list) of type...ListC i shall be glad to explain it again if my explanation is quite confusing. Can anyone suggest a better way for implementing such a requirement in the form of a pseudocode ? Thanks in advance VATSAG

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  • Javascript Detect Control Key Held on Mouseup

    - by Michael Mikowski
    I've searched a good deal, and can't seem to find a satisfactory solution. I hope someone can help. While I am using jQuery, I am also writing many thousands of lines of Javascript. So a "pure" javascript solution is just fine. I'm trying to determine if the control key is physically held down on a mouseup event. That's it; there are no other preconditions. Does anyone know how to do this reliably, cross-browser? I've tried storing this in a state variable by noting when the key is pressed and released: // BEGIN store control key status in hash_state $().bind('keydown','ctrl',function( arg_obj_e ){ hash_state.sw_ctrldn = true; console.debug( hash_state.sw_ctrldn ); }); $().bind('keyup','ctrl',function( arg_obj_e ){ hash_state.sw_ctrldn = false; console.debug( hash_state.sw_ctrldn ); }); // END store control key status in hash_state However, this really doesn't work. If you test this using firebug and watch the console, you will see that auto-repeat seems to happen, and the value toggles. I inspected the mouseup event to see if there is anything useful there, but to no avail: var debugEvent = function( arg_obj_e ){ var str = ''; for ( var attr in arg_obj_e ){ str += attr + ': ' + arg_obj_e[attr] + '\n'; } console.debug(str); } Any help would be appreciated.

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  • Asynchronous SQL Operations

    - by Paul Hatcherian
    I've got a problem I'm not sure how best to solve. I have an application which updates a database in response to ad hoc requests. One request in particular is quite common. The request is an update that by itself is quite simple, but has some complex preconditions. For this request the business layer first requests a set of data from the data layer. The business logic layer evaluated the data from the database and parameters from the request, from this the action to be performed is determined, and the request's response message(s) are created. The business layer now executes the actual update command that is the purpose of the request. This last step is the problem, this command is dependent on the state of the database, which might have changed since the business logic ran. Locking down the data read in this operation across several round-trips to the database doesn't seem like a good idea either. Is there a 'best-practice' way to accomplish something like this? Thanks!

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  • Need some ideas on how to acomplish this in Java (parsing strings)

    - by Matt
    Sorry I couldn't think of a better title, but thanks for reading! My ultimate goal is to read a .java file, parse it, and pull out every identifier. Then store them all in a list. Two preconditions are there are no comments in the file, and all identifiers are composed of letters only. Right now I can read the file, parse it by spaces, and store everything in a list. If anything in the list is a java reserved word, it is removed. Also, I remove any loose symbols that are not attached to anything (brackets and arithmetic symbols). Now I am left with a bunch of weird strings, but at least they have no spaces in them. I know I am going to have to re-parse everything with a . delimiter in order to pull out identifiers like System.out.print, but what about strings like this example: Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, After re-parsing by . I will be left with more crazy strings like: getLogger(MyHash getName()) log(Level SEVERE, How am I going to be able to pull out all the identifiers while leaving out all the trash? Just keep re-parsing by every symbol that could exist in java code? That seems rather lame and time consuming. I am not even sure if it would work completely. So, can you suggest a better way of doing this?

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  • Do Not Optimize Without Measuring

    - by Alois Kraus
    Recently I had to do some performance work which included reading a lot of code. It is fascinating with what ideas people come up to solve a problem. Especially when there is no problem. When you look at other peoples code you will not be able to tell if it is well performing or not by reading it. You need to execute it with some sort of tracing or even better under a profiler. The first rule of the performance club is not to think and then to optimize but to measure, think and then optimize. The second rule is to do this do this in a loop to prevent slipping in bad things for too long into your code base. If you skip for some reason the measure step and optimize directly it is like changing the wave function in quantum mechanics. This has no observable effect in our world since it does represent only a probability distribution of all possible values. In quantum mechanics you need to let the wave function collapse to a single value. A collapsed wave function has therefore not many but one distinct value. This is what we physicists call a measurement. If you optimize your application without measuring it you are just changing the probability distribution of your potential performance values. Which performance your application actually has is still unknown. You only know that it will be within a specific range with a certain probability. As usual there are unlikely values within your distribution like a startup time of 20 minutes which should only happen once in 100 000 years. 100 000 years are a very short time when the first customer tries your heavily distributed networking application to run over a slow WIFI network… What is the point of this? Every programmer/architect has a mental performance model in his head. A model has always a set of explicit preconditions and a lot more implicit assumptions baked into it. When the model is good it will help you to think of good designs but it can also be the source of problems. In real world systems not all assumptions of your performance model (implicit or explicit) hold true any longer. The only way to connect your performance model and the real world is to measure it. In the WIFI example the model did assume a low latency high bandwidth LAN connection. If this assumption becomes wrong the system did have a drastic change in startup time. Lets look at a example. Lets assume we want to cache some expensive UI resource like fonts objects. For this undertaking we do create a Cache class with the UI themes we want to support. Since Fonts are expensive objects we do create it on demand the first time the theme is requested. A simple example of a Theme cache might look like this: using System; using System.Collections.Generic; using System.Drawing; struct Theme { public Color Color; public Font Font; } static class ThemeCache { static Dictionary<string, Theme> _Cache = new Dictionary<string, Theme> { {"Default", new Theme { Color = Color.AliceBlue }}, {"Theme12", new Theme { Color = Color.Aqua }}, }; public static Theme Get(string theme) { Theme cached = _Cache[theme]; if (cached.Font == null) { Console.WriteLine("Creating new font"); cached.Font = new Font("Arial", 8); } return cached; } } class Program { static void Main(string[] args) { Theme item = ThemeCache.Get("Theme12"); item = ThemeCache.Get("Theme12"); } } This cache does create font objects only once since on first retrieve of the Theme object the font is added to the Theme object. When we let the application run it should print “Creating new font” only once. Right? Wrong! The vigilant readers have spotted the issue already. The creator of this cache class wanted to get maximum performance. So he decided that the Theme object should be a value type (struct) to not put too much pressure on the garbage collector. The code Theme cached = _Cache[theme]; if (cached.Font == null) { Console.WriteLine("Creating new font"); cached.Font = new Font("Arial", 8); } does work with a copy of the value stored in the dictionary. This means we do mutate a copy of the Theme object and return it to our caller. But the original Theme object in the dictionary will have always null for the Font field! The solution is to change the declaration of struct Theme to class Theme or to update the theme object in the dictionary. Our cache as it is currently is actually a non caching cache. The funny thing was that I found out with a profiler by looking at which objects where finalized. I found way too many font objects to be finalized. After a bit debugging I found the allocation source for Font objects was this cache. Since this cache was there for years it means that the cache was never needed since I found no perf issue due to the creation of font objects. the cache was never profiled if it did bring any performance gain. to make the cache beneficial it needs to be accessed much more often. That was the story of the non caching cache. Next time I will write something something about measuring.

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  • A little primer on using TFS with a small team

    - by johndoucette
    The scenario; A small team of 3 developers mostly in maintenance mode with traditional ASP.net, classic ASP, .Net integration services and utilities with the company’s third party packages, and a bunch of java-based Coldfusion web applications all under Visual Source Safe (VSS). They are about to embark on a huge SharePoint 2010 new construction project and wanted to use subversion instead VSS. TFS was a foreign word and smelled of “high cost” and of an “over complicated process”. Since they had no preconditions about the old TFS versions (‘05 & ‘08), it was fun explaining how simple it was to install a TFS server and get the ball rolling, with or without all the heavy stuff one sometimes associates with such a huge and powerful application management lifecycle product. So, how does a small team begin using TFS? 1. Start by using source control and migrate current VSS source trees into TFS. You can take the latest version or migrate the entire version history. It’s up to you on whether you want a clean start or need quick access to all the version notes and history of the bits. 2. Since most shops are mainly in maintenance mode with existing applications, begin using bug workitems for everything. When you receive an issue/bug from your current tracking system, manually enter the workitem in TFS right through Visual Studio. You can automate the integration to the current tracking system later or replace it entirely. Believe me, this thing is powerful and can handle even the largest of help desks. 3. With new construction, begin work with requirements and task workitems and follow the traditional sprint-based development lifecycle. Obviously, some minor training will be needed, but don’t fear, this is very intuitive and MSDN has a ton of lesson based labs and videos. 4. For the java developers, use the new Team Explorer Everywhere 2010 plugin (recently known as Teamprise). There is a seamless interface in Eclipse, but also a good command-line utility for other environments such as Dreamweaver. 5. Wait to fully integrate the whole workitem/project management/testing process until your team is familiar with the integrated workitems for bugs and code. After a while, you will see the team wanting more transparency into the work they are all doing and naturally, everyone will want workitems to help them organize the chaos! 6. Management will be limited in the value of the reports until you have a fully blown implementation of project planning, construction, build, deployment and testing. However, there are some basic “bug rate” reports and current backlog listings that can provide good information. Some notable explanations of TFS; Work Item Tracking and Project Management - A workitem represents the unit of work within the system which enables tracking of all activities produced by a user, whether it is a developer, business user, project manager or tester. The properties of a workitem such as linked changesets (checked-in code), who updated the data and when, the states and reasons for change, are all transitioned to a data warehouse within TFS for reporting purposes. A workitem can be defines as a "bug", "requirement", test case", or a "change request". They drive the work effort by the individual assigned to it and also provide a key role in defining what needs to be done. Workitems are the things the team needs to do to accomplish a goal. Test Case Management - Starting with a workitem known as a "test case", a tester (or developer) can now author and manage test cases within a formal test plan subsystem. Although TFS supports the test case workitem type, there is a new product known as the VS Test Professional 2010 which allows a tester to facilitate manual tests including fast forwarding steps in the process to arrive at the assertion point quickly. This repeatable process provides quick regression tests and can be conducted by the business user to ensure completeness during UAT. In addition, developers no longer can provide a response to a bug with the line "cannot reproduce". With every test run, attachments including the recorded session, captured environment configurations and settings, screen shots, intellitrace (debugging history), and in some cases if the lab manager is being used, a snapshot of the tested environment is available. Version Control - A modern system allowing shared check-in/check-out, excellent merge conflict resolution, Shelvesets (personal check-ins), branching/merging visualization, public workspaces, gated check-ins, security hierarchy capabilities, and changeset/workitem tracking. Knowing what was done with the code by any developer has become much easier to picture and resolve issues. Team Build - Automate the compilation process whether you need it to be whenever a developer checks-in code, periodically such as nightly builds for testers in the morning, or manual builds to be deployed into production. Each build can run through pre-determined tests, perform code analysis to see if the developer conforms to the team standards, and reject the build if either fails. Project Portal & Reporting - Provide management with a dashboard with insight into the project(s). "Where are we" in each step of the way including past iterations and the current burndown rate. Enabling this feature is easy as it seamlessly interfaces with existing SharePoint implementations.

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  • how do i make maximum minimum and average score statistic in this code? [on hold]

    - by goldensun player
    i wanna out put the maximum minimum and average score as a statistic category under the student ids and grades in the output file. how do i do that? here is the code: #include "stdafx.h" #include <iostream> #include <string> #include <fstream> #include <assert.h> using namespace std; int openfiles(ifstream& infile, ofstream& outfile); void Size(ofstream&, int, string); int main() { int num_student = 4, count, length, score2, w[6]; ifstream infile, curvingfile; char x; ofstream outfile; float score; string key, answer, id; do { openfiles(infile, outfile); // function calling infile >> key; // answer key for (int i = 0; i < num_student; i++) // loop over each student { infile >> id; infile >> answer; count = 0; length = key.size(); // length represents number of questions in exam from exam1.dat // size is a string function.... Size (outfile, length, answer); for (int j = 0; j < length; j++) // loop over each question { if (key[j] == answer[j]) count++; } score = (float) count / length; score2 = (int)(score * 100); outfile << id << " " << score2 << "%"; if (score2 >= 90)//<-----w[0] outfile << "A" << endl; else if (score2 >= 80)//<-----w[1] outfile << "B" << endl; else if (score2 >= 70)//<-----w[2] outfile << "C" << endl; else if (score2 >= 60)//<-----w[3] outfile << "D" << endl; else if (score2 >= 50)//<-----w[4] outfile << "E" << endl; else if (score2 < 50)//<-----w[5] outfile << "F" << endl; } cout << "Would you like to attempt a new trial? (y/n): "; cin >> x; } while (x == 'y' || x == 'Y'); return 0; } int openfiles(ifstream& infile, ofstream& outfile) { string name1, name2, name3, answerstring, curvedata; cin >> name1; name2; name3; if (name1 == "exit" || name2 == "exit" || name3 == "exit" ) return false; cout << "Input the name for the exam file: "; cin >> name1; infile.open(name1.c_str()); infile >> answerstring; cout << "Input the name for the curving file: "; cin >> name2; infile.open(name2.c_str()); infile >> curvedata; cout << "Input the name for the output: "; cin >> name3; outfile.open(name3.c_str()); return true; } void Size(ofstream& outfile, int length, string answer) { bool check;// extra answers, lesser answers... if (answer.size() > length) { outfile << "Unnecessary extra answers"; } else if (answer.size() < length) { outfile << "The remaining answers are incorrect"; } else { check = false; }; } and how do i use assert for preconditions and post conditional functions? i dont understand this that well...

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  • Problems using wxWidgets (wxMSW) within multiple DLL instances

    Preface I'm developing VST-plugins which are DLL-based software modules and loaded by VST-supporting host applications. To open a VST-plugin the host applications loads the VST-DLL and calls an appropriate function of the plugin while providing a native window handle, which the plugin can use to draw it's GUI. I managed to port my original VSTGUI code to the wxWidgets-Framework and now all my plugins run under wxMSW and wxMac but I still have problems under wxMSW to find a correct way to open and close the plugins and I am not sure if this is a wxMSW-only issue. Problem If I use any VST-host application I can open and close multiple instances of one of my VST-plugins without any problems. As soon as I open another of my VST-plugins besides my first VST-plugin and then close all instances of my first VST-plugin the application crashes after a short amount of time within the wxEventHandlerr::ProcessEvent function telling me that the wxTheApp object isn't valid any longer during execution of wxTheApp-FilterEvent (see below). So it seems to be that the wxTheApp objects was deleted after closing all instances of the first plugin and is no longer available for the second plugin. bool wxEvtHandler::ProcessEvent(wxEvent& event) { // allow the application to hook into event processing if ( wxTheApp ) { int rc = wxTheApp->FilterEvent(event); if ( rc != -1 ) { wxASSERT_MSG( rc == 1 || rc == 0, _T("unexpected wxApp::FilterEvent return value") ); return rc != 0; } //else: proceed normally } .... } Preconditions 1.) All my VST-plugins a dynamically linked against the C-Runtime and wxWidgets libraries. With regard to the wxWidgets forum this seemed to be the best way to run multiple instances of the software side by side. 2.) The DllMain of each VST-Plugin is defined as follows: // WXW #include "wx/app.h" #include "wx/defs.h" #include "wx/gdicmn.h" #include "wx/image.h" #ifdef __WXMSW__ #include <windows.h> #include "wx/msw/winundef.h" BOOL APIENTRY DllMain ( HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved ) { switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: { wxInitialize(); ::wxInitAllImageHandlers(); break; } case DLL_THREAD_ATTACH: break; case DLL_THREAD_DETACH: break; case DLL_PROCESS_DETACH: wxUninitialize(); break; } return TRUE; } #endif // __WXMSW__ class Application : public wxApp {}; IMPLEMENT_APP_NO_MAIN(Application) Question How can I prevent this behavior respectively how can I properly handle the wxTheApp object if I have multiple instances of different VST-plugins (DLL-modules), which are dynamically linked against the C-Runtime and wxWidgets libraries? Best reagards, Steffen

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  • Android USB Host Communication

    - by Kip Russell
    I'm working on a project that utilizes the USB Host capabilities in Android 3.2. I'm suffering from a deplorable lack of knowledge and talent regarding USB/Serial communication in general. I'm also unable to find any good example code for what I need to do. I need to read from a USB Communication Device. Ex: When I connect via Putty (on my PC) I enter: >GO And the device starts spewing out data for me. Pitch/Roll/Temp/Checksum. Ex: $R1.217P-0.986T26.3*60 $R1.217P-0.986T26.3*60 $R1.217P-0.987T26.3*61 $R1.217P-0.986T26.3*60 $R1.217P-0.985T26.3*63 I can send the initial 'GO' command from the Android device at which time I receive an echo of 'GO'. Then nothing else on any subsequent reads. How can I: 1) Send the 'go' command. 2) Read in the stream of data that results. The USB device I'm working with has the following interfaces (endpoints). Device Class: Communication Device (0x2) Interfaces: Interface #0 Class: Communication Device (0x2) Endpoint #0 Direction: Inbound (0x80) Type: Intrrupt (0x3) Poll Interval: 255 Max Packet Size: 32 Attributes: 000000011 Interface #1 Class: Communication Device Class (CDC) (0xa) Endpoint #0 Address: 129 Number: 1 Direction: Inbound (0x80) Type: Bulk (0x2) Poll Interval (0) Max Packet Size: 32 Attributes: 000000010 Endpoint #1 Address: 2 Number: 2 Direction: Outbound (0x0) Type: Bulk (0x2) Poll Interval (0) Max Packet Size: 32 Attributes: 000000010 I'm able to deal with permission, connect to the device, find the correct interface and assign the endpoints. I'm just having trouble figuring out which technique to use to send the initial command read the ensuing data. I'm tried different combinations of bulkTransfer and controlTransfer with no luck. Thanks. I'm using interface#1 as seen below: public AcmDevice(UsbDeviceConnection usbDeviceConnection, UsbInterface usbInterface) { Preconditions.checkState(usbDeviceConnection.claimInterface(usbInterface, true)); this.usbDeviceConnection = usbDeviceConnection; UsbEndpoint epOut = null; UsbEndpoint epIn = null; // look for our bulk endpoints for (int i = 0; i < usbInterface.getEndpointCount(); i++) { UsbEndpoint ep = usbInterface.getEndpoint(i); Log.d(TAG, "EP " + i + ": " + ep.getType()); if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) { if (ep.getDirection() == UsbConstants.USB_DIR_OUT) { epOut = ep; } else if (ep.getDirection() == UsbConstants.USB_DIR_IN) { epIn = ep; } } } if (epOut == null || epIn == null) { throw new IllegalArgumentException("Not all endpoints found."); } AcmReader acmReader = new AcmReader(usbDeviceConnection, epIn); AcmWriter acmWriter = new AcmWriter(usbDeviceConnection, epOut); reader = new BufferedReader(acmReader); writer = new BufferedWriter(acmWriter); }

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