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  • Classes and Objects in C++

    - by anurag18294
    class anurag { private: int rollno; char name[50]; int marks; float percen; void percentage(int num) { percen=(num/500)*100; } public: void getdata(void) { cout<<"\n\nEnter the name of the student:"; gets(name); cout<<"\n\nEnter the roll no: and the marks:"; cin>>rollno>>marks; percentage(marks); } void display(void) { cout<<"\n\nThe name of the student is:"; cout.write(name,50); cout<<"\n\nThe roll no: of the student is:"; cout<<rollno; cout<<"\n\n The marks obtained is:"<<marks; cout<<"\n\nThe percentage is:"<<percen; }}; void main() { clrscr(); anurag F; F.getdata(); F.display(); getch(); } why the following code is not giving the desired output?

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  • C program - Seg fault, cause of

    - by resonant_fractal
    Running this gives me a seg fault (gcc filename.c -lm), when i enter 6 (int) as a value. Please help me get my head around this. The intended functionality has not yet been implemented, but I need to know why I'm headed into seg faults already. Thanks! #include<stdio.h> #include<math.h> int main (void) { int l = 5; int n, i, tmp, index; char * s[] = {"Sheldon", "Leonard", "Penny", "Raj", "Howard"}; scanf("%d", &n); //Solve Sigma(Ai*2^(i-1)) = (n - k)/l if (n/l <= 1) printf("%s\n", s[n-1]); else { tmp = n; for (i = 1;;) { tmp = tmp - (l * pow(2,i-1)); if (tmp <= 5) { // printf("Breaking\n"); break; } ++i; } printf("Last index = %d\n", i); // ***NOTE*** //Value lies in next array, therefore ++i; index = tmp + pow(2, n-1); printf("%d\n", index); } return 0; }

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  • C Programming. How to deep copy a struct?

    - by user69514
    I have the following two structs where "child struct" has a "rusage struct" as an element. Then I create two structs of type "child" let's call them childA and childB How do I copy just the rusage struct from childA to childB? typedef struct{ int numb; char *name; pid_t pid; long userT; long systemT; struct rusage usage; }child; typedef struct{ struct timeval ru_utime; /* user time used */ struct timeval ru_stime; /* system time used */ long ru_maxrss; /* maximum resident set size */ long ru_ixrss; /* integral shared memory size */ long ru_idrss; /* integral unshared data size */ long ru_isrss; /* integral unshared stack size */ long ru_minflt; /* page reclaims */ long ru_majflt; /* page faults */ long ru_nswap; /* swaps */ long ru_inblock; /* block input operations */ long ru_oublock; /* block output operations */ long ru_msgsnd; /* messages sent */ long ru_msgrcv; /* messages received */ long ru_nsignals; /* signals received */ long ru_nvcsw; /* voluntary context switches */ long ru_nivcsw; /* involuntary context switches */ }rusage; I did the following, but I guess it copies the memory location, because if I changed the value of usage in childA, it also changes in childB. memcpy(&childA,&childB, sizeof(rusage)); I know that gives childB all the values from childA. I have already taken care of the others fields in childB, I just need to be able to copy the rusage struct called usage that resides in the "child" struct.

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  • Modifying bundled properties from visitor

    - by ravenspoint
    How should I modify the bundled properties of a vertex from inside a visitor? I would like to use the simple method of sub-scripting the graph, but the graph parameter passed into the visitor is const, so compiler disallows changes. I can store a reference to the graph in the visitor, but this seems weird. /** A visitor which identifies vertices as leafs or trees */ class bfs_vis_leaf_finder:public default_bfs_visitor { public: /** Constructor @param[in] total reference to int variable to store total number of leaves @param[in] g reference to graph ( used to modify bundled properties ) */ bfs_vis_leaf_finder( int& total, graph_t& g ) : myTotal( total ), myGraph( g ) { myTotal = 0; } /** Called when the search finds a new vertex If the vertex has no children, it is a leaf and the total leaf count is incremented */ template <typename Vertex, typename Graph> void discover_vertex( Vertex u, Graph& g) { if( out_edges( u, g ).first == out_edges( u, g ).second ) { myTotal++; //g[u].myLevel = s3d::cV::leaf; myGraph[u].myLevel = s3d::cV::leaf; } else { //g[u].myLevel = s3d::cV::tree; myGraph[u].myLevel = s3d::cV::tree; } } int& myTotal; graph_t& myGraph; };

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  • Convert this code from C++ to C#

    - by Alhariri
    please any one convert this code from c++ to c# beacuse i dont know how to read from file in c++ please help me int DoEnDe(int c) { SDES S(key); int i,n; n=10; //Number of Rounds unsigned char ch; FILE *fp; FILE *ft; fp=fopen(tfname,"w"); ft=fopen(sfname,"r"); if (fp==NULL) { printf("\nTarget File not opened SORRY"); getch(); fclose(fp); return(0); } if (ft==NULL) { printf("\nSource File not opened SORRY"); getch(); fclose(ft); return(0); } while (fread(&ch,1,1,ft)==1) { S.OUTPUT=ch; for (i=0;i<n;i++) { if (c==1) S.DES_Encryption(S.OUTPUT); if (c==2) S.DES_Decryption(S.OUTPUT); } fwrite(&S.OUTPUT,1,1,fp); } printf("\nCompleted!!!!!"); getch(); fclose(fp); fclose(ft); return(1); }

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  • Advice: Python Framework Server/Worker Queue management (not Website)

    - by Muppet Geoff
    I am looking for some advice/opinions of which Python Framework to use in an implementation of multiple 'Worker' PCs co-ordinated from a central Queue Manager. For completeness, the 'Worker' PCs will be running Audio Conversion routines (which I do not need advice on, and have standalone code that works). The Audio conversion takes a long time, and I need to co-ordinate an arbitrary number of the 'Workers' from a central location, handing them conversion tasks (such as where to get the source files, or where to ask for the job configuration) with them reporting back some additional info, such as the runtime of the converted audio etc. At present, I have a script that makes a webservice call to get the 'configuration' for a conversion task, based on source files located on the worker already (we manually copy the source files to the worker, and that triggers a conversion routine). I want to change this, so that we can distribute conversion tasks ("Oy you, process this: xxx") based on availability, and in an ideal world, based on pending tasks too. There is a chance that Workers can go offline mid-conversion (but this is not likely). All the workers are Windows based, the co-ordinator can be WIndows or Linux. I have (in my initial searches) come across the following - and I know that some are cross-dependent: Celery (with RabbitMQ) Twisted Django Using a framework, rather than home-brewing, seems to make more sense to me right now. I have a limited timeframe in which to develop this functional extension. An additional consideration would be using a Framework that is compatible with PyQT/PySide so that I can write a simple UI to display Queue status etc. I appreciate that the specifics above are a little vague, and I hope that someone can offer me a pointer or two. Again: I am looking for general advice on which Python framework to investigate further, for developing a Server/Worker 'Queue management' solution, for non-web activities (this is why DJango didn't seem the right fit).

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  • How do you use boost iterators

    - by Neil G
    It worked, and then I added the typedefs so that I could have a const_sparse_iterator as well. Now, when I compile this and try to use sparse_iterator, it says: /Users/neilrg/nn/src/./core/sparse_vector.h:331: error: invalid use of incomplete type 'struct sparse_vector<A>::sparse_iterator' Here's the code. More code here. tempalte<typename T> class sparse_vector { // There is more code at my previous question, but this might be enough...? private: template<typename base_type> class sparse_iterator_private : public boost::iterator_adaptor< sparse_iterator_private<base_type> // Derived , base_type // Base , value_type // Value , boost::random_access_traversal_tag // CategoryOrTraversal > { private: struct enabler {}; // a private type avoids misuse public: sparse_iterator_private() : sparse_iterator_private<base_type>::iterator_adaptor_(0) {} explicit sparse_iterator_private(typename array_type::iterator&& p) : sparse_iterator_private<base_type>::iterator_adaptor_(p) {} private: friend class boost::iterator_core_access; reference dereference() const { return this->base()->value; } }; public: typedef sparse_iterator_private<typename array_type::iterator> sparse_iterator; typedef sparse_iterator_private<typename array_type::const_iterator> const_sparse_iterator; };

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  • Issue selenium code maintenance

    - by Rajasankar
    I want to group the common methods in one file and use it. For example, login to a page using selenium may be used in multiple times. Define that in class A and call it in class B. However, it throws null pointer exception. class A has public void test_Login() throws Exception { try{ selenium.setTimeout("60000"); selenium.open("http://localhost"); selenium.windowFocus(); selenium.windowMaximize(); selenium.windowFocus(); selenium.type("userName", "admin"); selenium.type("password", "admin"); Result=selenium.isElementPresent("//input[@type='image']"); selenium.click("//input[@type='image']"); selenium.waitForPageToLoad(Timeout); } catch(Exception ex) { System.out.println(ex); ex.printStackTrace(); } } with all other java syntax in class B public void test_kk() throws Exception { try { a.test_Login(); } catch(Exception ex) { System.out.println(ex); ex.printStackTrace(); } } with all syntax. When I execute class B, I got this error, java.lang.NullPointerException at A.test_Login(A.java:32) at B.test_kk(savefile.java:58) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at junit.framework.TestCase.runTest(TestCase.java:168) at junit.framework.TestCase.runBare(TestCase.java:134) at com.thoughtworks.selenium.SeleneseTestCase.runBare(SeleneseTestCase.j ava:212) at junit.framework.TestResult$1.protect(TestResult.java:110) at junit.framework.TestResult.runProtected(TestResult.java:128) at junit.framework.TestResult.run(TestResult.java:113) at junit.framework.TestCase.run(TestCase.java:124) at junit.framework.TestSuite.runTest(TestSuite.java:232) at junit.framework.TestSuite.run(TestSuite.java:227) at junit.textui.TestRunner.doRun(TestRunner.java:116) at junit.textui.TestRunner.doRun(TestRunner.java:109) at junit.textui.TestRunner.run(TestRunner.java:77) at B.main(B.java:77) I hope someone must have tried this before. I may miss something here.

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  • IE7 & IE8 error executing function with ajax

    - by Yahreen
    I am loading an ajax page which executes an HTML5 video player script. The function for the Flash fallback is html5media(); : //Load 1st Case Study $("#splash").live('click', function (e) { $(this).fadeOut('slow', function () { $('#case-studies').load('case-study-1.html', function() { html5media(); //initiate Flash fallback }).fadeIn(); }); e.preventDefault(); }); This initial page load works fine in IE7 & IE8. The problem is once this page is loaded, there are links to 4 more videos which are loaded in again using ajax. I use this function: //Switcher function csClients(url, client) { $("#case-studies").fadeOut('slow', function() { $('#case-studies').load(url, function () { html5media(); //initiate Flash fallback }).fadeIn(); }); } //Page Loader $("#cs-client-list li.client1 a").live('click', function(e) { csClients('case-study-1.html', 'client1'); e.preventDefault(); }); Originally I was using return false; but none of the sub-page Flash videos would load in IE7. When I switched to preventDefault, the videos loaded in IE7 but still not in IE8. I also get a weird error in both IE7 & IE8 with no helpful feedback: Error on Page: Unspecified error. / (Line 49) Code: 0 (Char 5) URI: http://www.mysite.com This is line 49 in my index page: <section id="case-studies" class="main-section"> I have a feeling it has to do with calling html5media(); too many times? At a loss...

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  • jQuery: If user clicks out of div

    - by Paul Knopf
    I am creating a popup in query. All is well with the popup on hover. I made it see a timer starts when user's mouse leaves the div to close it. If he enters the div again before the timer is done, then the timer is cleared. This is fine, but what if a user clicks out of the div? I want that to also close the div. The only problem is that I don't want to attach click events to the wrapper on the page (because it includes the popout menu). I have seen techniques that wraps entire screen with a transparent div, and then attach a click event to hit. Although this may work, it confuses the user if he clicks the hidden div intending to click a link. He will have to click the link twice. Once two close the div (hiding the link), and another time to actually click think. Also, you loose in mouse cursors attached to any masked elements on the page (such as links cursor pointer, etc). There has to be a way to check if the user clicked out of the div without a modal and without attaching events to the entire page (page wrappers and child elements included). onclicksomewhereelse="closeme();" lol.

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  • Using an initializer_list on a map of vectors

    - by Hooked
    I've been trying to initialize a map of <ints, vector<ints> > using the new 0X standard, but I cannot seem to get the syntax correct. I'd like to make a map with a single entry with key:value = 1:<3,4 #include <initializer_list> #include <map> #include <vector> using namespace std; map<int, vector<int> > A = {1,{3,4}}; .... It dies with the following error using gcc 4.4.3: error: no matching function for call to std::map<int,std::vector<int,std::allocator<int> >,std::less<int>,std::allocator<std::pair<const int,std::vector<int,std::allocator<int> > > > >::map(<brace-enclosed initializer list>) Edit Following the suggestion by Cogwheel and adding the extra brace it now compiles with a warning that can be gotten rid of using the -fno-deduce-init-list flag. Is there any danger in doing so?

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  • Pointers and Addresses in C

    - by Mohit
    #include "stdio.h" main() { int i=3,*x; float j=1.5,*y; char k='c',*z; x=&i; y=&j; z=&k; printf("\nAddress of x= %u",x); printf("\nAddress of y= %u",y); printf("\nAddress of z= %u",z); x++; y++;y++;y++;y++; z++; printf("\nNew Address of x= %u",x); printf("\nNew Address of y= %u",y); printf("\nNew Address of z= %u",z); printf("\nNew Value of i= %d",i); printf("\nNew Value of j= %f",j); printf("\nNew Value of k= %c\n",k); } Output: Address of x= 3219901868 Address of y= 3219901860 Address of z= 3219901875 New Address of x= 3219901872 New Address of y= 3219901876 New Address of z= 3219901876 New Value of i= 3 New Value of j= 1.500000 New Value of k= c The new address of variable y and z are same. How can two variables have same address and et have different values? Note: I used gcc compiler on Ubuntu 9.04

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  • Console in VS 2012 Express for C++?

    - by Live2Code
    I'm very new to programming, so be nice. I was using Eclipse for C/C++ devs for a while, but it seemed quite buggy so I was advised to switch to Visual Studio Express. I'm just testing out with a simple "Hello World" program #include <iostream> #include <string> using namespace std; int main( int argc, char ** argv ) { string response; cout << "Gimme a string: " << flush; cin >> response; cout << "The string is: " << response << endl; system("pause"); return 0; } not much to go wrong there anyway, I noticed that there is no "console" like in Eclipse. All of the text pops up in a little command prompt window. And, also, this window closes right after displaying new text if there is no other things to do after it (like a cin). I have been told that I can use system("pause") but there has to be a better way. In Eclipse, the text would not suddenly disappear because the console window closed. i know this question might be a little confusing, comment and I'll try to explain what I'm saying. Or paste the codes into your Visual Studio 2012 Express Edition. But is there a way to display all of my text and whatever in a "console" as opposed to a command prompt-type window; and why does it always close before I can read the last thing?

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  • Trapping messages in .NET

    - by user350632
    How can i trap a Windows system message (like WM_SETTEXT) that was sent by some window (VLC player window in my case)? I've tried to inherit NativeWindow class and override WndProc like this: class VLCFilter : NativeWindow { System.IntPtr iHandle; const int WM_SETTEXT = 0x000C; public VLCFilter() { Process p = Process.GetProcessesByName("vlc")[0]; iHandle = p.MainWindowHandle; } protected override void WndProc(ref Message aMessage) { base.WndProc(ref aMessage); if (aMessage.HWnd != iHandle) return false; if (aMessage.Msg == WM_SETTEXT) { MessageBox.Show("VLC window text changed!"); } } } I have checked with Microsoft Spy++ that WM_SETTEXT message is sent by VLC player but my code doesn't seem to get the work done. I've refered mainly to: http://www.codeproject.com/kb/dotnet/devicevolumemonitor.aspx I'm trying to make this work for some time with no success. What am I doing wrong? What I am not doing? Maybe there is easier way to do this? My initial goal is to catch when VLC player (that could be playing somewhere in the background and is not emmbed in my application) repeats its playback (have noticed that WM_SETTEXT message is sent then and I'm trying to find it out like this).

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  • Visual C++ 2010, rvalue reference bug?

    - by Sergey Shandar
    Is it a bug in Visual C++ 2010 or right behaviour? template<class T> T f(T const &r) { return r; } template<class T> T f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); } I thought, the function f(T &&) should never be called but it's called with T = int &. The output: main.cpp(10): error C2338: no way main.cpp(17) : see reference to function template instantiation 'T f<int&>(T)' being compiled with [ T=int & ] Update 1 Do you know any C++x0 compiler as a reference? I've tried comeau online test-drive but could not compile r-value reference. Update 2 Workaround (using SFINAE): #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_reference.hpp> template<class T> T f(T &r) { return r; } template<class T> typename ::boost::disable_if< ::boost::is_reference<T>, T>::type f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); // f(5); // generates "no way" error, as expected. }

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  • SWIG_NewPointerObj and values always being nil

    - by Tom J Nowell
    I'm using SWIG to wrap C++ objects for use in lua, and Im trying to pass data to a method in my lua script, but it always comes out as 'nil' void CTestAI::UnitCreated(IUnit* unit){ lua_getglobal(L, "ai"); lua_getfield(L, -1, "UnitCreated"); swig_module_info *module = SWIG_GetModule( L ); swig_type_info *type = SWIG_TypeQueryModule( module, module, "IUnit *" ); SWIG_NewPointerObj(L,unit,type,0); lua_epcall(L, 1, 0); } Here is the lua code: function AI:UnitCreated(unit) if(unit == nil) then game:SendToConsole("I CAN HAS nil ?") else game:SendToConsole("I CAN HAS UNITS!!!?") end end unit is always nil. I have checked and in the C++ code, the unit pointer is never invalid/null I've also tried: void CTestAI::UnitCreated(IUnit* unit){ lua_getglobal(L, "ai"); lua_getfield(L, -1, "UnitCreated"); SWIG_NewPointerObj(L,unit,SWIGTYPE_p_IUnit,0); lua_epcall(L, 1, 0); } with identical results. Why is this failing? How do I fix it?

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  • How to compare two structure strings in C++

    - by Arvandor
    Ok, so this week in class we're working with arrays. I've got an assignment that wanted me to create a structure for an employee containing an employee ID, first name, last name, and wages. Then it has me ask users for input for 5 different employees all stored in an array of this structure, then ask them for a search field type, then a search value. Lastly, display all the information for all positive search results. I'm still new, so I'm sure it isn't a terribly elegant program, but what I'm trying to do now is figure out how to compare a user entered string with the string stored in the structure... I'll try to give all the pertinent code below. struct employee { int empid, string firstname, string lastname, float wage }; employee emparray[] = {}; employee value[] = {}; //Code for populating emparray and structure, then determine search field etc. cout << "Enter a search value: "; cin >> value.lastname; for(i = 0; i < 5; i++) { if(strcmp(value.lastname.c_str, emparray[i].lastname.c_str) == 0) { output(); } } Which... I thought would work, but it's giving me the following error.. Error 1 error C3867: 'std::basic_string<_Elem,_Traits,_Alloc>::c_str': function call missing argument list; use '&std::basic_string<_Elem,_Traits,_Alloc>::c_str' to create a pointer to member d:\myfile Any thoughts on what's going on? Is there a way to compare two .name notated strings without totally revamping the program? IF you want to drill me on best practices, please feel free, but also please try to solve my particular problem.

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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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  • Scope of the c++ using directive

    - by ThomasMcLeod
    From section 7.3.4.2 of the c++11 standard: A using-directive specifies that the names in the nominated namespace can be used in the scope in which the using-directive appears after the using-directive. During unqualified name lookup (3.4.1), the names appear as if they were declared in the nearest enclosing namespace which contains both the using-directive and the nominated namespace. [ Note: In this context, “contains” means “contains directly or indirectly”. —end note ] What do the second and third sentences mean exactly? Please give example. Here is the code I am attempting to understand: namespace A { int i = 7; } namespace B { using namespace A; int i = i + 11; } int main(int argc, char * argv[]) { std::cout << A::i << " " << B::i << std::endl; return 0; } It print "7 7" and not "7 18" as I would expect. Sorry for the typo, the program actually prints "7 11".

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  • StringBufferInputStream Question in Java

    - by JJG
    I want to read an input string and return it as a UTF8 encoded string. SO I found an example on the Oracle/Sun website that used FileInputStream. I didn't want to read a file, but a string, so I changed it to StringBufferInputStream and used the code below. The method parameter jtext, is some Japanese text. Actually this method works great. The question is about the deprecated code. I had to put @SuppressWarnings because StringBufferInputStream is deprecated. I want to know is there a better way to get a string input stream? Is it ok just to leave it as is? I've spent so long trying to fix this problem that I don't want to change anything now I seem to have cracked it. @SuppressWarnings("deprecation") private String readInput(String jtext) { StringBuffer buffer = new StringBuffer(); try { StringBufferInputStream sbis = new StringBufferInputStream (jtext); InputStreamReader isr = new InputStreamReader(sbis, "UTF8"); Reader in = new BufferedReader(isr); int ch; while ((ch = in.read()) > -1) { buffer.append((char)ch); } in.close(); return buffer.toString(); } catch (IOException e) { e.printStackTrace(); return null; } }

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  • Garbage data from serial port.

    - by sasayins
    Hi I wrote a code in Linux platform that read the data in serial port, my code below: int fd; char *rbuff=NULL; struct termios new_opt, old_opt; int ret; fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY); if( fd == -1 ) { printf("Can't open file: %s\n", strerror(errno)); return -1; } tcgetattr(fd, &old_opt); new_opt.c_cflag = B115200 | CS8 | CLOCAL | CREAD; new_opt.c_iflag = IGNPAR /*| ICRNL*/; new_opt.c_oflag = 0; new_opt.c_lflag = ICANON; tcsetattr(fd, TCSANOW, &new_opt); rbuff = malloc(NBUFF); printf("reading..\n"); memset(rbuff,0x00,NBUFF); ret = read(fd, rbuff, NBUFF); printf("value:%s",rbuff); if(ret == -1) { printf("Read error:%s\n",strerror(errno)); return -1; } tcsetattr(fd, TCSANOW, &old_opt); close(fd); My problem is the code above doesn't read the first data that was transmitted, then the second transmission the data is garbage, then the third is the normal data. Did I missed a setting in the serial port? Thanks.

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  • Getting the full-name of the current user, returns an empty string (C#/C++)

    - by Nir
    I try to get the full-name of the current log-in user (Fullname, not username). The following code C#, C++ works fine but on XP computers not connected to the Net, I get empty string as result if I run it ~20 minutes after login (It runs OK whithin the first ~20 minutes after login) A Win32 API (GetUserNameEx) is used rather that PrincipalContext since it PrincipalContext may takes up to 15 seconds when working offline. Any Help why am I getting an empty string as result though a user full name is specified??? - C# Code public static string CurrentUserFullName { get { const int EXTENDED_NAME_FORMAT_NAME_DISPLAY = 3; StringBuilder userName = new StringBuilder(256); uint length = (uint) userName.Capacity; string ret; if (GetUserNameEx(EXTENDED_NAME_FORMAT_NAME_DISPLAY, userName, ref length)) { ret = userName.ToString(); } else { int errorCode = Marshal.GetLastWin32Error(); throw new Win32Exception("GetUserNameEx Failed. Error code - " + errorCode); } return ret; } } [DllImport("Secur32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern bool GetUserNameEx(int nameFormat, StringBuilder lpNameBuffer, ref uint lpnSize); - Code in C++ #include "stdafx.h" #include <windows.h> #define SECURITY_WIN32 #include <Security.h> #pragma comment( lib, "Secur32.lib" ) int _tmain(int argc, _TCHAR* argv[]) { char szName[100]; ULONG nChars = sizeof( szName ); if ( GetUserNameEx( NameDisplay, szName, &nChars ) ) { printf( "Name: %s\n", szName); } else { printf( "Failed to GetUserNameEx\n" ); printf( "%d\n", GetLastError() ); } return 0; }

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  • What's the most trivial function that would benfit from being computed on a GPU?

    - by hanDerPeder
    Hi. I'm just starting out learning OpenCL. I'm trying to get a feel for what performance gains to expect when moving functions/algorithms to the GPU. The most basic kernel given in most tutorials is a kernel that takes two arrays of numbers and sums the value at the corresponding indexes and adds them to a third array, like so: __kernel void add(__global float *a, __global float *b, __global float *answer) { int gid = get_global_id(0); answer[gid] = a[gid] + b[gid]; } __kernel void sub(__global float* n, __global float* answer) { int gid = get_global_id(0); answer[gid] = n[gid] - 2; } __kernel void ranksort(__global const float *a, __global float *answer) { int gid = get_global_id(0); int gSize = get_global_size(0); int x = 0; for(int i = 0; i < gSize; i++){ if(a[gid] > a[i]) x++; } answer[x] = a[gid]; } I am assuming that you could never justify computing this on the GPU, the memory transfer would out weight the time it would take computing this on the CPU by magnitudes (I might be wrong about this, hence this question). What I am wondering is what would be the most trivial example where you would expect significant speedup when using a OpenCL kernel instead of the CPU?

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  • SQLite DB open time really long Problem

    - by sxingfeng
    I am using sqlite in c++ windows, And I have a db size about 60M, When I open the sqlite db, It takes about 13 second. sqlite3* mpDB; nRet = sqlite3_open16(szFile, &mpDB); And if I closed my application and reopen it again. It takse only less then 1 second. First, I thought It is because of disk cache. So I preload the 60M db file before sqlite open, and read the file using CFile, However, after preloading, the first time is still very slow. BOOL CQFilePro::PreLoad(const CString& strPath) { boost::shared_array<BYTE> temp = boost::shared_array<BYTE>(new BYTE[PRE_LOAD_BUFFER_LENGTH]); int nReadLength; try { CFile file; if (file.Open(strPath, CFile::modeRead) == FALSE) { return FALSE; } do { nReadLength = file.Read(temp.get(), PRE_LOAD_BUFFER_LENGTH); } while (nReadLength == PRE_LOAD_BUFFER_LENGTH); file.Close(); } catch(...) { } return TRUE; } My question is what is the difference between first open and second open. How can I accelerate the sqlite open-process.

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  • C++ Array vs vector

    - by blue_river
    when using C++ vector, time spent is 718 milliseconds, while when I use Array, time is almost 0 milliseconds. Why so much performance difference? int _tmain(int argc, _TCHAR* argv[]) { const int size = 10000; clock_t start, end; start = clock(); vector<int> v(size*size); for(int i = 0; i < size; i++) { for(int j = 0; j < size; j++) { v[i*size+j] = 1; } } end = clock(); cout<< (end - start) <<" milliseconds."<<endl; // 718 milliseconds int f = 0; start = clock(); int arr[size*size]; for(int i = 0; i < size; i++) { for(int j = 0; j < size; j++) { arr[i*size+j] = 1; } } end = clock(); cout<< ( end - start) <<" milliseconds."<<endl; // 0 milliseconds return 0; }

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