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  • waveInProc / Windows audio question...

    - by BTR
    I'm using the Windows API to get audio input. I've followed all the steps on MSDN and managed to record audio to a WAV file. No problem. I'm using multiple buffers and all that. I'd like to do more with the buffers than simply write to a file, so now I've got a callback set up. It works great and I'm getting the data, but I'm not sure what to do with it once I have it. Here's my callback... everything here works: // Media API callback void CALLBACK AudioRecorder::waveInProc(HWAVEIN hWaveIn, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2) { // Data received if (uMsg == WIM_DATA) { // Get wav header LPWAVEHDR mBuffer = (WAVEHDR *)dwParam1; // Now what? for (unsigned i = 0; i != mBuffer->dwBytesRecorded; ++i) { // I can see the char, how do get them into my file and audio buffers? cout << mBuffer->lpData[i] << "\n"; } // Re-use buffer mResultHnd = waveInAddBuffer(hWaveIn, mBuffer, sizeof(mInputBuffer[0])); // mInputBuffer is a const WAVEHDR * } } // waveInOpen cannot use an instance method as its callback, // so we create a static method which calls the instance version void CALLBACK AudioRecorder::staticWaveInProc(HWAVEIN hWaveIn, UINT uMsg, DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD_PTR dwParam2) { // Call instance version of method reinterpret_cast<AudioRecorder *>(dwParam1)->waveInProc(hWaveIn, uMsg, dwInstance, dwParam1, dwParam2); } Like I said, it works great, but I'm trying to do the following: Convert the data to short and copy into an array Convert the data to float and copy into an array Copy the data to a larger char array which I'll write into a WAV Relay the data to an arbitrary output device I've worked with FMOD a lot and I'm familiar with interleaving and all that. But FMOD dishes everything out as floats. In this case, I'm going the other way. I guess I'm basically just looking for resources on how to go from LPSTR to short, float, and unsigned char. Thanks much in advance!

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  • Obtaining command line arguments in a QT application

    - by morpheous
    The following snippet is from a little app I wrote using the QT framework. The idea is that the app can be run in batch mode (i.e. called by a script) or can be run interactively. It is important therefore, that I am able to parse command line arguments in order to know which mode in which to run etc. [Edit] I am debugging using QTCreator 1.3.1 on Ubuntu Karmic. The arguments are passed in the normal way (i.e. by adding them via the 'Project' settings in the QTCreator IDE). When I run the app, it appears that the arguments are not being passed to the application. The code below, is a snippet of my main() function. int main(int argc, char *argv[]) { //Q_INIT_RESOURCE(application); try { QApplication the_app(argc, argv); //trying to get the arguments into a list QStringList cmdline_args = QCoreApplication::arguments(); // Code continues ... } catch (const MyCustomException &e) { return 1; } return 0; } [Update] I have identified the problem - for some reason, although argc is correct, the elements of argv are empty strings. I put this little code snippet to print out the argv items - and was horrified to see that they were all empty. for (int i=0; i< argc; i++){ std::string s(argv[i]); //required so I can see the damn variable in the debugger std::cout << s << std::endl; } Does anyone know what on earth is going on (or a hammer)?

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  • Checking if a function has C-linkage at compile-time

    - by scjohnno
    Is there any way to check if a given function is declared with C-linkage (that is, with extern "C") at compile-time? I am developing a plugin system. Each plugin can supply factory functions to the plugin-loading code. However, this has to be done via name (and subsequent use of GetProcAddress or dlsym). This requires that the functions be declared with C-linkage so as to prevent name-mangling. It would be nice to be able to throw a compiler error if the referred-to function is declared with C++-linkage (as opposed to finding out at runtime when a function with that name does not exist). Here's a simplified example of what I mean: extern "C" void my_func() { } void my_other_func() { } // Replace this struct with one that actually works template<typename T> struct is_c_linkage { static const bool value = true; }; template<typename T> void assertCLinkage(T *func) { static_assert(is_c_linkage<T>::value, "Supplied function does not have C-linkage"); } int main() { assertCLinkage(my_func); // Should compile assertCLinkage(my_other_func); // Should NOT compile } Thanks.

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  • Displaying cookies as key=value for all domains?

    - by OverTheRainbow
    Hello, This question pertains to the use of the cookie-capable WebClient derived class presented in the How can I get the WebClient to use Cookies? question. I'd like to use a ListBox to... 1) display each cookie individually as "key=value" (the For Each loop displays all of them as one string), and 2) be able to display all cookies, regardless of the domain from which they came ("www.google.com", here): Imports System.IO Imports System.Net Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim webClient As New CookieAwareWebClient Const URL = "http://www.google.com" Dim response As String response = webClient.DownloadString(URL) RichTextBox1.Text = response 'How to display cookies as key/value in ListBox? 'PREF=ID=5e770c1a9f279d5f:TM=1274032511:LM=1274032511:S=1RDPaKJKpoMT9T54 For Each mycc In webClient.cc.GetCookies(New Uri(URL)) ListBox1.Items.Add(mycc.ToString) Next End Sub End Class Public Class CookieAwareWebClient Inherits WebClient Public cc As New CookieContainer() Private lastPage As String Protected Overrides Function GetWebRequest(ByVal address As System.Uri) As System.Net.WebRequest Dim R = MyBase.GetWebRequest(address) If TypeOf R Is HttpWebRequest Then With DirectCast(R, HttpWebRequest) .CookieContainer = cc If Not lastPage Is Nothing Then .Referer = lastPage End If End With End If lastPage = address.ToString() Return R End Function End Class Thank you.

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  • Need help profiling .NET caching extension method.

    - by rockinthesixstring
    I've got the following extension Public Module CacheExtensions Sub New() End Sub Private sync As New Object() Public Const DefaultCacheExpiration As Integer = 1200 ''# 20 minutes <Extension()> Public Function GetOrStore(Of T)(ByVal cache As Cache, ByVal key As String, ByVal generator As Func(Of T)) As T Return cache.GetOrStore(key, If(generator IsNot Nothing, generator(), Nothing), DefaultCacheExpiration) End Function <Extension()> Public Function GetOrStore(Of T)(ByVal cache As Cache, ByVal key As String, ByVal generator As Func(Of T), ByVal expireInSeconds As Double) As T Return cache.GetOrStore(key, If(generator IsNot Nothing, generator(), Nothing), expireInSeconds) End Function <Extension()> Public Function GetOrStore(Of T)(ByVal cache As Cache, ByVal key As String, ByVal obj As T) As T Return cache.GetOrStore(key, obj, DefaultCacheExpiration) End Function <Extension()> Public Function GetOrStore(Of T)(ByVal cache As Cache, ByVal key As String, ByVal obj As T, ByVal expireInSeconds As Double) As T Dim result = cache(key) If result Is Nothing Then SyncLock sync If result Is Nothing Then result = If(obj IsNot Nothing, obj, Nothing) cache.Insert(key, result, Nothing, DateTime.Now.AddSeconds(expireInSeconds), cache.NoSlidingExpiration) End If End SyncLock End If Return DirectCast(result, T) End Function End Module From here, I'm using the extension is a TagService to get a list of tags Public Function GetTagNames() As List(Of String) Implements Domain.ITagService.GetTags ''# We're not using a dynamic Cache key because the list of TagNames ''# will persist across all users in all regions. Return HttpRuntime.Cache.GetOrStore(Of List(Of String))("TagNamesOnly", Function() _TagRepository.Read().Select(Function(t) t.Name).OrderBy(Function(t) t).ToList()) End Function All of this is pretty much straight forward except when I put a breakpoint on _TagRepository.Read(). The problem is that it is getting called on every request, when I thought that it is only to be called when Result Is Nothing Am I missing something here?

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  • Splitting Code into Headers/Source files

    - by cam
    I took the following code from the examples page on Asio class tcp_connection : public boost::enable_shared_from_this<tcp_connection> { public: typedef boost::shared_ptr<tcp_connection> pointer; static pointer create(boost::asio::io_service& io_service) { return pointer(new tcp_connection(io_service)); } tcp::socket& socket() { return socket_; } void start() { message_ = make_daytime_string(); boost::asio::async_write(socket_, boost::asio::buffer(message_), boost::bind(&tcp_connection::handle_write, shared_from_this(), boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } private: tcp_connection(boost::asio::io_service& io_service) : socket_(io_service) { } void handle_write(const boost::system::error_code& /*error*/, size_t /*bytes_transferred*/) { } tcp::socket socket_; std::string message_; }; I'm relatively new to C++ (from a C# background), and from what I understand, most people would split this into header and source files (declaration/implementation, respectively). Is there any reason I can't just leave it in the header file if I'm going to use it across many source files? If so, are there any tools that will automatically convert it to declaration/implementation for me? Can someone show me what this would look like split into header/source file for an example (or just part of it, anyway)? I get confused around weird stuff like thistypedef boost::shared_ptr<tcp_connection> pointer; Do I include this in the header or the source? Same with tcp::socket& socket() I've read many tutorials, but this has always been something that has confused me about C++.

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  • c++ programming- Tryin to get a number within an array that is twice the average

    - by max
    i have been assigned to set up an array with points. I am told to get the maximum value, average, nd within this same array, if any point in the array is twice the average, i should cout an "outlier." So far i have gotten the average and maximum numbers in the array. but i am unable to set the programme to cout the outlier. Instead it gives me a multiple of the average. pls help! here is the programme; int main() { const int max = 10; int ary[max]={4, 32, 9, 7, 14, 12, 13, 17, 19, 18}; int i,maxv; double out,sum=0; double av; maxv= ary[0]; for(i=0; i } cout<<"maximum value: "< for(i=0; i sum = sum + ary[i]; av = sum / max; } cout<<"average: "< out = av * 2; if(ary[i]out) { cout<<"outlier: "< return 0; }

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  • Generating an NSDictionary from an SQL statement.

    - by Ed Wist
    I am trying to generate an NSDictonary that can be used to populate a listview with data I retrieved from an SQL statement. when I go to create an array and add them it adds the arrays for ALL my keys and not just for the current key. I've tried a removeAllObjects on the array but for some reason that destroys ALL my data that I already put in the dictionary. //open the database if(sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) { const char *sql = "select alphaID, word from words order by word"; sqlite3_stmt *selectStatement; //prepare the select statement int returnValue = sqlite3_prepare_v2(database, sql, -1, &selectStatement, NULL); if(returnValue == SQLITE_OK) { NSMutableArray *NameArray = [[NSMutableArray alloc] init]; NSString *alphaTemp = [[NSString alloc] init]; //loop all the rows returned by the query. while(sqlite3_step(selectStatement) == SQLITE_ROW) { NSString *currentAlpha = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectStatement, 1)]; NSString *definitionName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectStatement, 2)]; if (alphaTemp == nil){ alphaTemp = currentAlpha; } if ([alphaTemp isEqualToString:(NSString *)currentAlpha]) { [NameArray addObject:definitionName]; } else if (alphaTemp != (NSString *)currentAlpha) { [self.words setObject:NameArray forKey:currentAlpha]; [NameArray removeAllObjects]; [NameArray addObject:definitionName]; } } } The Statement above adds all the "keys" but then removes all the array elements for all keys. if I take out the removeAllKeys it adds ALL the array elements for ALL keys. I don't want this I want it to add the array elements FOR the specific key then move on to the next key. in the end I want a NSDictonary with A (array) Alpha (string) Apple (string) B (array) Beta (string) Ball (string) C (array) Code (string) ...

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  • how to write binary copy of structure array to file

    - by cerr
    I would like to write a binary image of a structure array to a binary file. I have tried this so far: #include <stdio.h> #include <string.h> #define NUM 256 const char *fname="binary.bin"; typedef struct foo_s { int intA; int intB; char string[20]; }foo_t; void main (void) { foo_t bar[NUM]; bar[0].intA = 10; bar[0].intB = 999; strcpy(bar[0].string,"Hello World!"); Save(bar); printf("%s written succesfully!\n",fname); } int Save(foo_t* pData) { FILE *pFile; int ptr = 0; int itr = 0; pFile = fopen(fname, "w"); if (pFile == NULL) { printf("couldn't open %s\n", fname); return; } for (itr = 0; itr<NUM; itr++) { for (ptr=0; ptr<sizeof(foo_t); ptr++) { fputc((unsigned char)*((&pData[itr])+ptr), pFile); } fclose(pFile); } } but the compiler is saying aggregate value used where an integer was expected fputc((unsigned char)*((&pData[itr])+ptr), pFile); and I don't quite understand why, what am I doing wrong? Thanks!

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  • C++ class derivation and superconstructor confusion

    - by LukeN
    Hey, in a tutorial C++ code, I found this particular piece of confusion: PlasmaTutorial1::PlasmaTutorial1(QObject *parent, const QVariantList &args) : Plasma::Applet(parent, args), // <- Okay, Plasma = namespace, Applet = class m_svg(this), // <- A member function of class "Applet"? m_icon("document") // <- ditto? { m_svg.setImagePath("widgets/background"); // this will get us the standard applet background, for free! setBackgroundHints(DefaultBackground); resize(200, 200); } I'm not new to object oriented programming, so class derivation and super-classes are nothing complicated, but this syntax here got me confused. The header file defines the class like this: class PlasmaTutorial1 : public Plasma::Applet { Similar to above, namespace Plasma and class Applet. But what's the public doing there? I fear that I already know the concept but don't grasp the C++ syntax/way of doing it. In this question I picked up that these are called "superconstructors", at least that's what stuck in my memory, but I don't get this to the full extend. If we glance back at the first snippet, we see Constructor::Class(...) : NS::SuperClass(...), all fine 'till here. But what are m_svg(this), m_icon("document") doing there? Is this some kind of method to make these particular functions known to the derivated class? Is this part of C++ basics or more immediate? While I'm not completly lost in C++, I feel much more at home in C :) Most of the OOP I have done so far was done in D, Ruby or Python. For example in D I would just define class MyClass : MySuperClass, override what I needed to and call the super class' constructor if I'd need to.

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  • Why initialize an object to empty

    - by ProgEnthu
    I am learning windows programming with the help of MSDN.Why would somebody initialize an object like the following? WNDCLASS wc = { }; Will this zero all the memory of the object? Whole source code is following: #ifndef UNICODE #define UNICODE #endif #include <windows.h> LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam); int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow) { // Register the window class. const wchar_t CLASS_NAME[] = L"Sample Window Class"; WNDCLASS wc = { }; wc.lpfnWndProc = WindowProc; wc.hInstance = hInstance; wc.lpszClassName = CLASS_NAME; RegisterClass(&wc); // Create the window. HWND hwnd = CreateWindowEx( 0, // Optional window styles. CLASS_NAME, // Window class L"Learn to Program Windows", // Window text WS_OVERLAPPEDWINDOW, // Window style // Size and position CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, // Parent window NULL, // Menu hInstance, // Instance handle NULL // Additional application data ); if (hwnd == NULL) { return 0; } ShowWindow(hwnd, nCmdShow); // Run the message loop. MSG msg = { }; while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return 0; } LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch (uMsg) { case WM_DESTROY: PostQuitMessage(0); return 0; case WM_PAINT: { PAINTSTRUCT ps; HDC hdc = BeginPaint(hwnd, &ps); FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1)); EndPaint(hwnd, &ps); } return 0; } return DefWindowProc(hwnd, uMsg, wParam, lParam); }

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  • How to make ActiveRecord work with legacy partitioned/sharded databases/tables?

    - by Utensil
    thanks for your time first...after all the searching on google, github and here, and got more confused about the big words(partition/shard/fedorate),I figure that I have to describe the specific problem I met and ask around. My company's databases deals with massive users and orders, so we split databases and tables in various ways, some are described below: way database and table name shard by (maybe it's should be called partitioned by?) YZ.X db_YZ.tb_X order serial number last three digits YYYYMMDD. db_YYYYMMDD.tb date YYYYMM.DD db_YYYYMM.tb_ DD date too The basic concept is that databases and tables are seperated acording to a field(not nessissarily the primary key), and there are too many databases and too many tables, so that writing or magically generate one database.yml config for each database and one model for each table isn't possible or at least not the best solution. I looked into drnic's magic solutions, and datafabric, and even the source code of active record, maybe I could use ERB to generate database.yml and do database connection in around filter, and maybe I could use named_scope to dynamically decide the table name for find, but update/create opertions are bounded to "self.class.quoted_table_name" so that I couldn't easily get my problem solved. And even I could generate one model for each table, because its amount is up to 30 most. But this is just not DRY! What I need is a clean solution like the following DSL: class Order < ActiveRecord::Base shard_by :order_serialno do |key| [get_db_config_by(key), #because some or all of the databaes might share the same machine in a regular way or can be configed by a hash of regex, and it can also be a const get_db_name_by(key), get_tb_name_by(key), ] end end Can anybody enlight me? Any help would be greatly appreciated~~~~

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  • Using boost::iterator_adaptor

    - by Neil G
    I wrote a sparse vector class (see #1, #2.) I would like to provide two kinds of iterators: The first set, the regular iterators, can point any element, whether set or unset. If they are read from, they return either the set value or value_type(), if they are written to, they create the element and return the lvalue reference. Thus, they are: Random Access Traversal Iterator and Readable and Writable Iterator The second set, the sparse iterators, iterate over only the set elements. Since they don't need to lazily create elements that are written to, they are: Random Access Traversal Iterator and Readable and Writable and Lvalue Iterator I also need const versions of both, which are not writable. I can fill in the blanks, but not sure how to use boost::iterator_adaptor to start out. Here's what I have so far: class iterator : public boost::iterator_adaptor< iterator // Derived , value_type* // Base , boost::use_default // Value , boost::?????? // CategoryOrTraversal > class sparse_iterator : public boost::iterator_adaptor< iterator // Derived , value_type* // Base , boost::use_default // Value , boost::random_access_traversal_tag? // CategoryOrTraversal >

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  • iPhone - Using sql database - insert statement failing

    - by Satyam svv
    Hi, I'm using sqlite database in my iphone app. I've a table which has 3 integer columns. I'm using following code to write to that database table. -(BOOL)insertTestResult { NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; NSString* dataBasePath = [documentsDirectory stringByAppendingPathComponent:@"test21.sqlite3"]; BOOL success = NO; sqlite3* database = 0; if(sqlite3_open([dataBasePath UTF8String], &database) == SQLITE_OK) { BOOL res = (insertResultStatement == nil) ? createStatement(insertResult, &insertResultStatement, database) : YES; if(res) { int i = 1; sqlite3_bind_int(insertResultStatement, 0, i); sqlite3_bind_int(insertResultStatement, 1, i); sqlite3_bind_int(insertResultStatement, 2, i); int err = sqlite3_step(insertResultStatement); if(SQLITE_ERROR == err) { NSAssert1(0, @"Error while inserting Result. '%s'", sqlite3_errmsg(database)); success = NO; } else { success = YES; } sqlite3_finalize(insertResultStatement); insertResultStatement = nil; } } sqlite3_close(database); return success;} The command sqlite3_step is always giving err as 19. I'm not able to understand where's the issue. Tables are created using following queries: CREATE TABLE [Patient] (PID integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,PFirstName text NOT NULL,PLastName text,PSex text NOT NULL,PDOB text NOT NULL,PEducation text NOT NULL,PHandedness text,PType text) CREATE TABLE PatientResult(PID INTEGER,PFreeScore INTEGER NOT NULL,PForcedScore INTEGER NOT NULL,FOREIGN KEY (PID) REFERENCES Patient(PID)) I've only one entry in Patient table with PID = 1 BOOL createStatement(const char* query, sqlite3_stmt** stmt, sqlite3* database){ BOOL res = (sqlite3_prepare_v2(database, query, -1, stmt, NULL) == SQLITE_OK); if(!res) NSLog( @"Error while creating %s => '%s'", query, sqlite3_errmsg(database)); return res;}

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  • Reflection and Generics get value of property

    - by GigaPr
    Hi i am trying to implement a generic method which allows to output csv file public static void WriteToCsv<T>(List<T> list) where T : new() { const string attachment = "attachment; filename=PersonList.csv"; HttpContext.Current.Response.Clear(); HttpContext.Current.Response.ClearHeaders(); HttpContext.Current.Response.ClearContent(); HttpContext.Current.Response.AddHeader("content-disposition", attachment); HttpContext.Current.Response.ContentType = "text/csv"; HttpContext.Current.Response.AddHeader("Pragma", "public"); bool isFirstRow = true; foreach (T item in list) { //Get public properties PropertyInfo[] propertyInfo = item.GetType().GetProperties(); while (isFirstRow) { WriteColumnName(propertyInfo); isFirstRow = false; } Type type = typeof (T); StringBuilder stringBuilder = new StringBuilder(); foreach (PropertyInfo info in propertyInfo) { //string value ???? I am trying to get the value of the property info for the item object } HttpContext.Current.Response.Write(stringBuilder.ToString()); HttpContext.Current.Response.Write(Environment.NewLine); } HttpContext.Current.Response.End(); } but I am not able to get the value of the object's property Any suggestion? Thanks

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  • Creating a process in ASP.NET MVC controller

    - by GRKamath
    I have a requirement to run an application through my MVC controller. To get the installation path I used following link (I used answer provided by Fredrik Mörk). It worked and I could able to run the exe through a process. The problem occurred when I deployed this solution on IIS where it did not create the process as it was creating in local dev environment. Can anybody tell me how to create a windows process through a solution which is hosted on IIS ? private string GetPathForExe(string fileName) { private const string keyBase = @"SOFTWARE\Wow6432Node\MyApplication"; RegistryKey localMachine = Registry.LocalMachine; RegistryKey fileKey = localMachine.OpenSubKey(string.Format(@"{0}\{1}", keyBase, fileName)); object result = null; if (fileKey != null) { result = fileKey.GetValue("InstallPath"); } fileKey.Close(); return (string)result; } public void StartMyApplication() { Process[] pname = Process.GetProcessesByName("MyApplication"); if (pname.Length == 0) { string appDirectory = GetPathForExe("MyApplication"); Directory.SetCurrentDirectory(appDirectory); ProcessStartInfo procStartInfo = new ProcessStartInfo("MyApplication.exe"); procStartInfo.WindowStyle = ProcessWindowStyle.Hidden; Process proc = new Process(); proc.StartInfo = procStartInfo; proc.Start(); } }

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  • C++ Boolean problem (comparison between two arrays)

    - by Martin
    Hello! I have a problem to do. I already did some part of it, however I stuck and don't know exactly what to do next. The question: " You are given two arrays of ints, named A and B. One contains AMAXELEMENTS and the other contains BMAXELEMENTS. Write a Boolean-valued function that returns true if there is at least one point in A that is the same as a point in B, and false if there is no match between two arrays. " The two arrays are made up by me, I think if I know how to compare two arrays I will be fine, and I will be able to finish my problem. This is what I have so far (I changed AMAXELEMENTS to AMAX, and BMAXELEMENTS to BMAX): #include <iostream> using namespace std; int main(){ const int AMAX=5, BMAX=6; int i; bool c1=true,c2=false; int A[AMAX]={2,4,1,5,9}; int B[BMAX]={9,12,32,43,23,11}; for(i=0;i<BMAX;i++) if (B[i]==A[i]) // <---- I think this part has to look different, but I can't figure it out. cout<<c1<<endl; else cout<< c2<<endl; return 0; }

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  • C++ and Dependency Injection in unit testing

    - by lhumongous
    Suppose I have a C++ class like so: class A { public: A() { } void SetNewB( const B& _b ) { m_B = _b; } private: B m_B; } In order to unit test something like this, I would have to break A's dependency on B. Since class A holds onto an actual object and not a pointer, I would have to refactor this code to take a pointer. Additionally, I would need to create a parent interface class for B so I can pass in my own fake of B when I test SetNewB. In this case, doesn't unit testing with dependency injection further complicate the existing code? If I make B a pointer, I'm now introducing heap allocation, and some piece of code is now responsible for cleaning it up (unless I use ref counted pointers). Additionally, if B is a rather trivial class with only a couple of member variables and functions, why introduce a whole new interface for it instead of just testing with an instance of B? I suppose you could make the argument that it would be easier to refactor A by using an interface. But are there some cases where two classes might need to be tightly coupled?

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  • Problems with variadic function (C)

    - by morpheous
    I have the following function from some legacy code that I am maintaining. long getMaxStart(long start, long count, const myStruct *s1, ...) { long i1, maxstart; myStruct *s2; va_list marker; maxstart = start; /*BUGFIX: 003 */ /*(va_start(marker, count);*/ va_start(marker, s1); for (i1 = 1; i1 <= count; i1++) { s2 = va_arg(marker, myStruct *); /* <- s2 is assigned null here */ maxstart = MAX(maxstart, s2->firstvalid); /* <- SEGV here */ } va_end(marker); return (maxstart); } When the function is called with only one myStruct argument, it causes a SEGV. The code compiled and run without crashing on an XP, when I compiled it using VS2005. I have now moved the code to Ubuntu Karmic and I am having problems with the stricter compiler on Linux. Is anyone able to spot what is causing the parameter not to be read correctly in the var_arg() statement? I am compiling using gcc version 4.4.1

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  • Measuring the CPU frequency scaling effect

    - by Bryan Fok
    Recently I am trying to measure the effect of the cpu scaling. Is it accurate if I use this clock to measure it? template<std::intmax_t clock_freq> struct rdtsc_clock { typedef unsigned long long rep; typedef std::ratio<1, clock_freq> period; typedef std::chrono::duration<rep, period> duration; typedef std::chrono::time_point<rdtsc_clock> time_point; static const bool is_steady = true; static time_point now() noexcept { unsigned lo, hi; asm volatile("rdtsc" : "=a" (lo), "=d" (hi)); return time_point(duration(static_cast<rep>(hi) << 32 | lo)); } }; Update: According to the comment from my another post, I believe redtsc cannot use for measure the effect of cpu frequency scaling because the counter from the redtsc does not affected by the CPU frequency, am i right?

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  • C++ Declaring an enum within a class

    - by bporter
    In the following code snippet, the Color enum is declared within the Car class in order to limit the scope of the enum and to try not to "pollute" the global namespace. class Car { public: enum Color { RED, BLUE, WHITE }; void SetColor( Car::Color color ) { _color = color; } Car::Color GetColor() const { return _color; } private: Car::Color _color; }; (1) Is this a good way to limit the scope of the Color enum? Or, should I declare it outside of the Car class, but possibly within its own namespace or struct? I just came across this article today, which advocates the latter and discusses some nice points about enums: http://gamesfromwithin.com/stupid-c-tricks-2-better-enums. (2) In this example, when working within the class, is it best to code the enum as Car::Color, or would just Color suffice? (I assume the former is better, just in case there is another Color enum declared in the global namespace. That way, at least, we are explicit about the enum to we are referring.) Thanks in advance for any input on this.

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  • Declaring an enum within a class

    - by bporter
    In the following code snippet, the Color enum is declared within the Car class in order to limit the scope of the enum and to try not to "pollute" the global namespace. class Car { public: enum Color { RED, BLUE, WHITE }; void SetColor( Car::Color color ) { _color = color; } Car::Color GetColor() const { return _color; } private: Car::Color _color; }; (1) Is this a good way to limit the scope of the Color enum? Or, should I declare it outside of the Car class, but possibly within its own namespace or struct? I just came across this article today, which advocates the latter and discusses some nice points about enums: http://gamesfromwithin.com/stupid-c-tricks-2-better-enums. (2) In this example, when working within the class, is it best to code the enum as Car::Color, or would just Color suffice? (I assume the former is better, just in case there is another Color enum declared in the global namespace. That way, at least, we are explicit about the enum to we are referring.) Thanks in advance for any input on this.

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  • Templates, Function Pointers and C++0x

    - by user328543
    One of my personal experiments to understand some of the C++0x features: I'm trying to pass a function pointer to a template function to execute. Eventually the execution is supposed to happen in a different thread. But with all the different types of functions, I can't get the templates to work. #include `<functional`> int foo(void) {return 2;} class bar { public: int operator() (void) {return 4;}; int something(int a) {return a;}; }; template <class C> int func(C&& c) { //typedef typename std::result_of< C() >::type result_type; typedef typename std::conditional< std::is_pointer< C >::value, std::result_of< C() >::type, std::conditional< std::is_object< C >::value, std::result_of< typename C::operator() >::type, void> >::type result_type; result_type result = c(); return result; } int main(int argc, char* argv[]) { // call with a function pointer func(foo); // call with a member function bar b; func(b); // call with a bind expression func(std::bind(&bar::something, b, 42)); // call with a lambda expression func( [](void)->int {return 12;} ); return 0; } The result_of template alone doesn't seem to be able to find the operator() in class bar and the clunky conditional I created doesn't compile. Any ideas? Will I have additional problems with const functions?

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  • SQLITE crash when no data present in table

    - by johnblack45
    Hey, Im having a problem with my app that causes it to crash when no data is present in the table when using a table view. I have tested my code and it works fine as long as there is data present but i need it to work when there is no data present. -(void)initialiseTableData { NSMutableArray *array = [[NSMutableArray alloc]init]; sqlite3 *db = [iCaddyAppDelegate getNewDBConnection]; sqlite3_stmt *statement; const char *sql = "select courseId, courseName, totalPar, totalyardage, holePars, holeYardages, holeStrokeIndexs from Course"; if(sqlite3_prepare_v2(db, sql, -1, &statement, NULL)!= SQLITE_OK) { NSAssert1(0,@"Error preparing statement",sqlite3_errmsg(db)); sqlite3_close(db); } else { while (sqlite3_step(statement) == SQLITE_ROW) { Course *temp = [[Course alloc]init]; temp.courseId = sqlite3_column_int(statement,0); temp.courseName = [NSString stringWithFormat:@"%s",(char*)sqlite3_column_text(statement,1)]; temp.totalPar =sqlite3_column_int(statement,2); temp.totalYardage =sqlite3_column_int(statement,3); NSString tempHolePars = [NSString stringWithFormat:@"%s",(char)sqlite3_column_text(statement,4)]; NSString tempHoleYardages = [NSString stringWithFormat:@"%s",(char)sqlite3_column_text(statement,5)]; NSString tempHoleStrokeIndexes = [NSString stringWithFormat:@"%s",(char)sqlite3_column_text(statement,6)]; NSArray *temp1 = [tempHolePars componentsSeparatedByString:@":"]; NSArray *temp2 = [tempHoleYardages componentsSeparatedByString:@":"]; NSArray *temp3 = [tempHoleStrokeIndexes componentsSeparatedByString:@":"]; for(int i = 0; i<=17; i++) { NSString *temp1String = [temp1 objectAtIndex:i]; [temp.holePars insertObject:temp1String atIndex:i]; NSString *temp2String = [temp2 objectAtIndex:i]; [temp.holeYardages insertObject:temp2String atIndex:i]; NSString *temp3String = [temp3 objectAtIndex:i]; [temp.holeStrokeIndexes insertObject:temp3String atIndex:i]; } [array addObject:temp]; } self.list = array; [self.table reloadData]; } }

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  • How can I tell when the Text of a System.Windows.Forms.GroupBox wraps to the next line?

    - by fre0n
    I'm creating a GroupBox at runtime and setting its Text property. Usually, the text is only on one line, but sometimes it wraps. The problem is that the controls contained in the GroupBox cover up the GroupBox's text. What I'd like to do is determine if and when the text wraps. Specifically, I'd like to determine how much extra height the wrapped text takes up as compared to a single line. That way, I can reposition the GroupBox's controls and adjust its height. Initially, I thought I'd do this by calling the GroupBox's CreateGraphics() method, and using the Graphics to measure the string. Something like this: private void SetGroupBoxText(GroupBox grp, string text) { const int somePadding = 10; Graphics g = grp.CreateGraphics(); SizeF textSize = g.MeasureString(text, grp.Font); if (textSize.Width > (grp.Width - somePadding)) { // Adjust height, etc. } } The problem is that the size generated by g.MeasureString(text, grp.Font) doesn't seem to be accurate. I determined that it wasn't accurate by putting enough of a single character to cause a wrap, then measuring the resulting string. For example, it took 86 pipes (|) to until a wrap happened. When I measured that string, its width was ~253. And it took 16 capital W's to force a wrap - its string had a width of ~164. These were the two extremes that I tested. My GroupBox's width was 189. (a's took 29 and had a width of ~180, O's took 22 and had a width of ~189) Does anyone have any ideas? (hacks, WinAPI, etc. are welcome solutions)

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