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  • Problem in storing the dynamic data in NSMutableArray?

    - by Rajendra Bhole
    I want to develop an application in which firstly i was develop an structure code for storing X and y axis. struct TCo_ordinates { float x; float y; }; . Then in drawRect method i generating an object of structure like. struct TCo_ordinates *tCoordianates; Now I drawing the graph of Y-Axis its code is. fltX1 = 30; fltY1 = 5; fltX2 = fltX1; fltY2 = 270; CGContextMoveToPoint(ctx, fltX1, fltY1); CGContextAddLineToPoint(ctx, fltX2, fltY2); NSArray *hoursInDays = [[NSArray alloc] initWithObjects:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"10",@"11",@"12", nil]; for(int intIndex = 0 ; intIndex < [hoursInDays count] ; fltY2-=20, intIndex++) { CGContextSetRGBStrokeColor(ctx, 2, 2, 2, 1); //CGContextSetRGBStrokeColor(ctx, 1.0f/255.0f, 1.0f/255.0f, 1.0f/255.0f, 1.0f); CGContextMoveToPoint(ctx, fltX1-3 , fltY2-40); CGContextAddLineToPoint(ctx, fltX1+3, fltY2-40); CGContextSelectFont(ctx, "Helvetica", 14.0, kCGEncodingMacRoman); CGContextSetTextDrawingMode(ctx, kCGTextFill); CGContextSetRGBFillColor(ctx, 0, 255, 255, 1); CGAffineTransform xform = CGAffineTransformMake( 1.0, 0.0, 0.0, -1.0, 0.0, 0.0); CGContextSetTextMatrix(ctx, xform); const char *arrayDataForYAxis = [[hoursInDays objectAtIndex:intIndex] UTF8String]; float x1 = fltX1-23; float y1 = fltY2-37; CGContextShowTextAtPoint(ctx, x1, y1, arrayDataForYAxis, strlen(arrayDataForYAxis)); CGContextStrokePath(ctx); Now i want to store generated the values of x1 and y1 in NSMutableArray dynamically, for that i was written the code. NSMutableArray *yAxisCoordinates = [[NSMutableArray alloc] autorelease]; for(int yObject = 0; yObject < intIndex; yObject++) { [yAxisCoordinates insertObject:(tCoordianates->x = x1,tCoordianates->y = y1) atIndex:yObject]; } But it didn't working. How i store the x1 and y1 values in yAxisCoordinates object. The above code is correct?????????????

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  • Sort a list of pointers.

    - by YuppieNetworking
    Hello all, Once again I find myself failing at some really simple task in C++. Sometimes I wish I could de-learn all I know from OO in java, since my problems usually start by thinking like Java. Anyways, I have a std::list<BaseObject*> that I want to sort. Let's say that BaseObject is: class BaseObject { protected: int id; public: BaseObject(int i) : id(i) {}; virtual ~BaseObject() {}; }; I can sort the list of pointer to BaseObject with a comparator struct: struct Comparator { bool operator()(const BaseObject* o1, const BaseObject* o2) const { return o1->id < o2->id; } }; And it would look like this: std::list<BaseObject*> mylist; mylist.push_back(new BaseObject(1)); mylist.push_back(new BaseObject(2)); // ... mylist.sort(Comparator()); // intentionally omitted deletes and exception handling Until here, everything is a-ok. However, I introduced some derived classes: class Child : public BaseObject { protected: int var; public: Child(int id1, int n) : BaseObject(id1), var(n) {}; virtual ~Child() {}; }; class GrandChild : public Child { public: GrandChild(int id1, int n) : Child(id1,n) {}; virtual ~GrandChild() {}; }; So now I would like to sort following the following rules: For any Child object c and BaseObject b, b<c To compare BaseObject objects, use its ids, as before. To compare Child objects, compare its vars. If they are equal, fallback to rule 2. GrandChild objects should fallback to the Child behavior (rule 3). I initially thought that I could probably do some casts in Comparator. However, this casts away constness. Then I thought that probably I could compare typeids, but then everything looked messy and it is not even correct. How could I implement this sort, still using list<BaseObject*>::sort ? Thank you

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  • No matter what, I can't get this stupid progress bar to update from a thread!

    - by Synthetix
    I have a Windows app written in C (using gcc/MinGW) that works pretty well except for a few UI problems. One, I simply cannot get the progress bar to update from a thread. In fact, I probably can't get ANY UI stuff to update. Basically, I have a spawned thread that does some processing, and from that thread I attempt to update the progress bar in the main thread. I tried this by using PostMessage() to the main hwnd, but no luck even though I can do other things like open message boxes. However, it's unclear whether the message box is getting called within the thread or on the main thread. Here's some code: //in header/globally accessible HWND wnd; //main application window HWND progress_bar; //progress bar typedef struct { //to pass to thread DWORD mainThreadId; HWND mainHwnd; char *filename; } THREADSTUFF; //callback function LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam){ switch(msg){ case WM_CREATE:{ //create progress bar progress_bar = CreateWindowEx( 0, PROGRESS_CLASS, (LPCTSTR)NULL, WS_CHILD | WS_VISIBLE, 79,164,455,15, hwnd, (HMENU)20, NULL, NULL); break; } case WM_COMMAND:{ if(LOWORD(wParam)==2){ //do some processing in a thread //struct of stuff I need to pass to thread THREADSTUFF *threadStuff; threadStuff = (THREADSTUFF*)malloc(sizeof(*threadStuff)); threadStuff->mainThreadId = GetCurrentThreadId(); threadStuff->mainHwnd = hwnd; threadStuff->filename = (void*)&filename; hThread1 = CreateThread(NULL,0,convertFile (LPVOID)threadStuff,0,NULL); }else if(LOWORD(wParam)==5){ //update progress bar MessageBox(hwnd,"I got a message!", "Message", MB_OK | MB_ICONINFORMATION); PostMessage(progress_bar,PBM_STEPIT,0,CLR_DEFAULT); } break; } } } This all seems to work okay. The problem is in the thread: DWORD WINAPI convertFile(LPVOID params){ //get passed params, this works perfectly fine THREADSTUFF *tData = (THREADSTUFF*)params; MessageBox(tData->mainHwnd,tData->filename,"File name",MB_OK | MB_ICONINFORMATION); //yep PostThreadMessage(tData->mainThreadId,WM_COMMAND,5,0); //only shows message PostMessage(tData->mainHwnd,WM_COMMAND,5,0); //only shows message } When I say, "only shows message," that means the MessageBox() function in the callback works, but not the PostMessage() to update the position of the progress bar. What am I missing?

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  • Problem initialing a unicode string

    - by Simon
    Hey All. Atm im working with native API calls and i have to get RtlInitUnicodeString to work. The way i use: const WCHAR wcMutex[] = L"String1"; UNICODE_STRING unicodeMutexBuffer; RtlInitUnicodeString(&unicodeMutexBuffer,wcMutex); now my problem the project doesnt compile , i get this error: Error argument of type "UNICODE_STRING*" is incompatible with type of "PUNICODE_STRING" but in my old Driver kit , i used same way to initialize the unicode string struct

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  • Where are the function literals c++?

    - by academicRobot
    First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one.

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  • passing an array struture as an array

    - by Matias
    I'm having trouble passing a struture array as a parameter of a funtion struct Estructure{ int a; intb; }; and a funtion Begining(Estructure &s1[]) { //modifi the estructure s1 }; and the main would be something like this int main() { Estructure m[200]; Begining(m); }; is this valid?

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  • Loosely coupled implicit conversion

    - by ltjax
    Implicit conversion can be really useful when types are semantically equivalent. For example, imagine two libraries that implement a type identically, but in different namespaces. Or just a type that is mostly identical, except for some semantic-sugar here and there. Now you cannot pass one type into a function (in one of those libraries) that was designed to use the other, unless that function is a template. If it's not, you have to somehow convert one type into the other. This should be trivial (or otherwise the types are not so identical after-all!) but calling the conversion explicitly bloats your code with mostly meaningless function-calls. While such conversion functions might actually copy some values around, they essentially do nothing from a high-level "programmers" point-of-view. Implicit conversion constructors and operators could obviously help, but they introduce coupling, so that one of those types has to know about the other. Usually, at least when dealing with libraries, that is not the case, because the presence of one of those types makes the other one redundant. Also, you cannot always change libraries. Now I see two options on how to make implicit conversion work in user-code: The first would be to provide a proxy-type, that implements conversion-operators and conversion-constructors (and assignments) for all the involved types, and always use that. The second requires a minimal change to the libraries, but allows great flexibility: Add a conversion-constructor for each involved type that can be externally optionally enabled. For example, for a type A add a constructor: template <class T> A( const T& src, typename boost::enable_if<conversion_enabled<T,A>>::type* ignore=0 ) { *this = convert(src); } and a template template <class X, class Y> struct conversion_enabled : public boost::mpl::false_ {}; that disables the implicit conversion by default. Then to enable conversion between two types, specialize the template: template <> struct conversion_enabled<OtherA, A> : public boost::mpl::true_ {}; and implement a convert function that can be found through ADL. I would personally prefer to use the second variant, unless there are strong arguments against it. Now to the actual question(s): What's the preferred way to associate types for implicit conversion? Are my suggestions good ideas? Are there any downsides to either approach? Is allowing conversions like that dangerous? Should library implementers in-general supply the second method when it's likely that their type will be replicated in software they are most likely beeing used with (I'm thinking of 3d-rendering middle-ware here, where most of those packages implement a 3D vector).

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  • access Elf section header table

    - by idealistikz
    Assume I have the following: Elf_FIle_Header *fileHeader //struct pointer, points to start of the Elf file header fileHeader->offset //byte offset from start of file to section headers Elf_Section_Header *sectionHeader = (Elf_Section_Header *)(char *)fileHeader + fileHeader->offset Why doesn't the above line point me to the start of the section header table? How do I point to the start of the section header table?

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  • What is the best way to do Bit Field manipulation in Python?

    - by ZebZiggle
    I'm reading some MPEG Transport Stream protocol over UDP and it has some funky bitfields in it (length 13 for example). I'm using the "struct" library to do the broad unpacking, but is there a simple way to say "Grab the next 13 bits" rather than have to hand-tweak the bit manipulation? I'd like something like the way C does bit fields (without having to revert to C). Suggestions?

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  • C/C++ __restrict type

    - by aaa
    hello. Is there a way to define using typedef integral/float type which implies no aliasng? something equivalent to (but primitive construct): template < typename T > struct restrict { T* __restrict data; };

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  • Why would you avoid C++ keywords in Java?

    - by Joshua Swink
    A popular editor uses highlighting to help programmers avoid using C++ keywords in Java. The following words are displayed using the same colors as a syntax error: auto delete extern friend inline redeclared register signed sizeof struct template typedef union unsigned operator Why would this be considered important?

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  • non blocking TCP-acceptor not reading from socket

    - by Abruzzo Forte e Gentile
    I have the code below implementing a NON-Blocking TCP acceptor. Clients are able to connect without any problem and the writing seems occurring as well, but the acceptor doesn't read anything from the socket and the call to read() blocks indefinitely. Am I using some wrong setting for the acceptor? Kind Regards AFG int main(){ create_programming_socket(); poll_programming_connect(); while(1){ poll_programming_read(); } } int create_programming_socket(){ int cnt = 0; p_listen_socket = socket( AF_INET, SOCK_STREAM, 0 ); if( p_listen_socket < 0 ){ return 1; } int flags = fcntl( p_listen_socket, F_GETFL, 0 ); if( fcntl( p_listen_socket, F_SETFL, flags | O_NONBLOCK ) == -1 ){ return 1; } bzero( (char*)&p_serv_addr, sizeof(p_serv_addr) ); p_serv_addr.sin_family = AF_INET; p_serv_addr.sin_addr.s_addr = INADDR_ANY; p_serv_addr.sin_port = htons( p_port ); if( bind( p_listen_socket, (struct sockaddr*)&p_serv_addr , sizeof(p_serv_addr) ) < 0 ) { return 1; } listen( p_listen_socket, 5 ); return 0; } int poll_programming_connect(){ int retval = 0; static socklen_t p_clilen = sizeof(p_cli_addr); int res = accept( p_listen_socket, (struct sockaddr*)&p_cli_addr, &p_clilen ); if( res > 0 ){ p_conn_socket = res; int flags = fcntl( p_conn_socket, F_GETFL, 0 ); if( fcntl( p_conn_socket, F_SETFL, flags | O_NONBLOCK ) == -1 ){ retval = 1; }else{ p_connected = true; } }else if( res == -1 && ( errno == EWOULDBLOCK || errno == EAGAIN ) ) { //printf( "poll_sock(): accept(c_listen_socket) would block\n"); }else{ retval = 1; } return retval; } int poll_programming_read(){ int retval = 0; bzero( p_buffer, 256 ); int numbytes = read( p_conn_socket, p_buffer, 255 ); if( numbytes > 0 ) { fprintf( stderr, "poll_sock(): read() read %d bytes\n", numbytes ); pkt_struct2_t tx_buf; int fred; int i; } else if( numbytes == -1 && ( errno == EWOULDBLOCK || errno == EAGAIN ) ) { //printf( "poll_sock(): read() would block\n"); } else { close( p_conn_socket ); p_connected = false; retval = 1; } return retval; }

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  • C Array of string

    - by Meko
    HI. This is maybe simple question but I want to create two dimensional array and add it string like in java string str = "text" ; string [][] array = new [][] string ; array[i][j] = str ; But in C there is no string .I tried like this but here strcpy() gives error.It returns to assembly code. I am trying to read line by line from text and split line by space and add them to structure.But first I think that I must add each line and row in array and then making iteration and adding to structures fields. static const char filename[] = "student.txt"; FILE *file = fopen ( filename, "r" ); char line [ 128 ]; /* or other suitable maximum line size */ char delims [ ]=" "; char *result =NULL; char list[15]; char arra[128][128]; int i=0; int j=0; struct { char gruppa[10]; char familiya[20]; int uchaste; struct { int firsth; int second; int third; int fourht; int fifth; } exam; }student; for(i=0; i<128; i++) for(j=0; j<128; j++) arra[i][j] = '\0'; for(i=0; i<15; i++) list[i] = '\0'; if ( file != NULL ) { while ( fgets ( line, sizeof line, file ) != NULL ) { result = strtok(line,delims); while (result !=NULL) { strcpy(list,("%s",result)); strcpy(arra[i][j],list); // Here it gives errror j++; result = strtok(NULL,delims); } j=0; i++; } fclose ( file ); } else { perror ( filename ); } getchar(); return 0; }

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  • Linked list Recursion ...

    - by epsilon_G
    hey , I'd like to make a recursive function using C++ I make this class class linklist { private: struct node { int data; node *link; }*p; void linklist::print_num(node* p) { if (p != NULL) { cout << p->data << " "; print_num (p->link); } } in the main program what should I write ...

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  • Undefined template methods trick ?

    - by Matthieu M.
    A colleague of mine told me about a little piece of design he has used with his team that sent my mind boiling. It's a kind of traits class that they can specialize in an extremely decoupled way. I've had a hard time understanding how it could possibly work, and I am still unsure of the idea I have, so I thought I would ask for help here. We are talking g++ here, specifically the versions 3.4.2 and 4.3.2 (it seems to work with both). The idea is quite simple: 1- Define the interface // interface.h template <class T> struct Interface { void foo(); // the method is not implemented, it could not work if it was }; // // I do not think it is necessary // but they prefer free-standing methods with templates // because of the automatic argument deduction // template <class T> void foo(Interface<T>& interface) { interface.foo(); } 2- Define a class, and in the source file specialize the interface for this class (defining its methods) // special.h class Special {}; // special.cpp #include "interface.h" #include "special.h" // // Note that this specialization is not visible outside of this translation unit // template <> struct Interface<Special> { void foo() { std::cout << "Special" << std::endl; } }; 3- To use, it's simple too: // main.cpp #include "interface.h" class Special; // yes, it only costs a forward declaration // which helps much in term of dependencies int main(int argc, char* argv[]) { Interface<Special> special; foo(special); return 0; }; It's an undefined symbol if no translation unit defined a specialization of Interface for Special. Now, I would have thought this would require the export keyword, which to my knowledge has never been implemented in g++ (and only implemented once in a C++ compiler, with its authors advising anyone not to, given the time and effort it took them). I suspect it's got something to do with the linker resolving the templates methods... Do you have ever met anything like this before ? Does it conform to the standard or do you think it's a fortunate coincidence it works ? I must admit I am quite puzzled by the construct...

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  • Another void C# question

    - by Jim Jones
    Have a type in the header files I'm working with called VTVOID it is the type of a struct element and a number of parameters. In the header file defining types is the line #define VTVOID void I read in another discussion the void maps to System.Void however when I plug that into the C# code I get the error "System.Void cannot be used in C# -- use typeof(void) to get the void object." So what type do I plug in? Jim

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  • [Visual C++]Forcing memory alignment of variables/data-structures

    - by John
    I'm looking at using SSE and I gather aligning data on 16byte boundaries is recommended. There are two cases to consider: float data[4]; struct myystruct { float x,y,z,w; }; I'm not sure the first case can be done explicitly, though there's perhaps a compiler option I could use? In the second case I remember being able to control packing in old versions of GCC several years back, is this still possible?

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  • missing subscript c++

    - by Makenshi
    right now c++ is giving me this error: error C2087 'color' missing subscript first time i get this and i dont know what to do .< hope any1 can help me struct Color{ float r; float g; float b; };Color color[][]; and im using it here for(int i=0;i<cubes;i++) { color[i][0].r = fRand();color[i][0].g=fRand(.5);color[i][0].b=fRand(); ...etc

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  • Connection between Properties of Entities in Data Oriented Design

    - by sharethis
    I want to start with an example illustrating my question. The following way it is done in the most games. class car { vec3 position; vec3 rotation; mesh model; imge texture; void move(); // modify position and rotation void draw(); // use model, texture, ... }; vector<car> cars; for(auto i = cars.begin(); i != cars.end(); ++i) { i->move(); i->draw(); } Data oriented design means to process the same calculation on the hole batch of data at once. This way it takes more advantage out of the processor cache. struct movedata { vec3 position; vec3 rotation; }; struct drawdata { mesh model; imge texture; }; vector<movedata> movedatas; vector<drawdata> drawdatas; for(auto i = movedatas.begin(); i != movedatas.end(); ++i) { // modify position and rotation } for(auto i = drawdatas.begin(); i != drawdatas.end(); ++i) { // use model, texture, ... } But there comes a point where you need to find other properties according to an entity. For example if the car crashes, I do not need the drawdata and the movedata any more. So I need to delete the entries of this entity in all vectors. The entries are not linked by code. So my question is the following. How are properties of the same entity conceptually linked in a data oriented design?

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