Search Results

Search found 6123 results on 245 pages for 'unsigned char'.

Page 216/245 | < Previous Page | 212 213 214 215 216 217 218 219 220 221 222 223  | Next Page >

• Fibonacci in C works great with 1 - 18 but 19 does nothing at all...

  - by shevron

  Yeah right... we are forced to programm some good old C at our university... ;) So here's my problem: We got the assignment to program a little program that show a fibonacci sequence from 1 to n 1 to 18 works great. But from 19 the program does nothing at all and just exit as it's done. I can not find the error... so please give me a hint. :) #include #include #include #include int main(int argc, char **argv) { pid_t pid; int fib[argc]; int i, size; size = strtol(argv[1], NULL, 0L); fib[0] = 0; fib[1] = 1; pid = fork(); printf("size = %d \n", size); if(pid == 0){ for(i = 2; i 0){ // Parent, because pid 0 wait(NULL); printf("\n"); exit(1); } } Thanks already!

  Read the article

• How to wrap a C function whose parameters are pointer to structs, so that it can be called from Lua?

  - by pierr

  I have the follwing C function. How should I wrap it so it can be called from a Lua script? typedef struct tagT{ int a ; int b ; } type_t; int lib_a_f_4(type_t *t) { return t->a * t->b ; } I know how to wrapr it if the function parameter type were int or char *. Should I use table type for a C structure? EDIT: I am using SWIG for the wraping , according to this doc, It seems that I should automatically have this funtion new_type_t(2,3) , but it is not the case. If you wrap a C structure, it is also mapped to a Lua userdata. By adding a metatable to the userdata, this provides a very natural interface. For example, struct Point{ int x,y; }; is used as follows: p=example.new_Point() p.x=3 p.y=5 print(p.x,p.y) 3 5 Similar access is provided for unions and the data members of C++ classes. C structures are created using a function new_Point(), but for C++ classes are created using just the name Point().

  Read the article

• C++ Suppress Automatic Initialization and Destruction

  - by Travis G

  How does one suppress the automatic initialization and destruction of a type? While it is wonderful that T buffer[100] automatically initializes all the elements of buffer, and destroys them when they fall out of scope, this is not the behavior I want. #include <iostream> static int created = 0, destroyed = 0; struct S { S() { ++created; } ~S() { ++destroyed; } }; template <typename T, size_t KCount> class Array { private: T m_buffer[KCount]; public: Array() { // some way to suppress the automatic initialization of m_buffer } ~Array() { // some way to suppress the automatic destruction of m_buffer } }; int main() { { Array<S, 100> arr; } std::cout << "Created:\t" << created << std::endl; std::cout << "Destroyed:\t" << destroyed << std::endl; return 0; } The output of this program is: Created: 100 Destroyed: 100 I would like it to be: Created: 0 Destroyed: 0 My only idea is to make m_buffer some trivially constructed and destructed type like char and then rely on operator[] to wrap the pointer math for me, although this seems like a horribly hacked solution. Another solution would be to use malloc and free, but that gives a level of indirection that I do not want.

  Read the article

• How to make command-line options mandatory with GLib?

  - by ahe

  I use GLib to parse some command-line options. The problem is that I want to make two of those options mandatory so that the program terminates with the help screen if the user omits them. My code looks like this: static gint line = -1; static gint column = -1; static GOptionEntry options[] = { {"line", 'l', 0, G_OPTION_ARG_INT, &line, "The line", "L"}, {"column", 'c', 0, G_OPTION_ARG_INT, &column, "The column", "C"}, {NULL} }; ... int main(int argc, char** argv) { GError *error = NULL; GOptionContext *context; context = g_option_context_new ("- test"); g_option_context_add_main_entries (context, options, NULL); if (!g_option_context_parse(context, &argc, &argv, &error)) { usage(error->message, context); } ... return 0; } If I omit one of those parameters or both on the command-line g_option_context_parse() still succeeds and the values in question (line and or column) are still -1. How can I tell GLib to fail parsing if the user doesn't pass both options on the command-line? Maybe I'm just blind but I couldn't find a flag I can put into my GOptionEntry data structure to tell it to make those fields mandatory. Of course I could check if one of those variables is still -1 but then the user could just have passed this value on the command-line and I want to print a separate error message if the values are out of range.

  Read the article

• ISO C90 forbids mixed declarations and code sscanf

  - by Need4Sleep

  I'm getting a strange error attempting to compile my unit test code,. For some reason the compiler treats my sscanf call as a mixed declaration? I don't quite understand, here is the entire error: cc1: warnings being treated as errors /home/brlcad/brlcad/src/libbn/tests/bn_complex.c: In function 'main': /home/brlcad/brlcad/src/libbn/tests/bn_complex.c:53: error: ISO C90 forbids mixed declarations and code make[2]: *** [src/libbn/tests/CMakeFiles/tester_bn_complex.dir/bn_complex.c.o] Error 1 make[1]: *** [src/libbn/tests/CMakeFiles/tester_bn_complex.dir/all] Error 2 make: *** [all] Error 2 int main(int argc, char *argv[]) { double expRe1, expIm2, expSqRe1, expSqIm2; double actRe1, actIm2, actSqRe1, actSqIm2; actRe1 = actIm2 = actSqRe1 = actSqIm2 = expRe1 = expIm2 = expSqRe1 = expSqIm2 = 0.0; bn_complex_t com1,com2; //a struct that holds two doubles if(argc < 5) bu_exit(1, "ERROR: Invalid parameters[%s]\n", argv[0]); sscanf(argv[1], "%lf,%lf", &com1.re, &com1.im); /* Error is HERE */ sscanf(argv[2], "%lf,%lf", &com2.re, &com2.im); sscanf(argv[3], "%lf,%lf", &expRe1, &expIm2); sscanf(argv[4], "%lf,%lf", &expSqRe1, &expSqIm2); test_div(com1, com2, &actRe1, &actIm2); test_sqrt(com1,com2, &actSqRe1, &actSqIm2); if((fabs(actRe1 - expRe1) < 0.00001) || (fabs(actIm2 - expIm2) < 0.00001)){ printf("Division failed...\n"); return 1; } if((fabs(actSqRe1 - expSqRe1) < 0.00001) || (fabs(actSqIm2 - expSqIm2) < 0.00001)){ printf("Square roots failed...\n"); return 1; } return 0; }

  Read the article

• C# Multidimensional Array Definition

  - by Blaenk

  Can someone help me convert this to C#. I've already spent more time than I would have liked trying to do it myself and it's preventing me from actually getting any work done. I guess it seems like C# has a limitation regarding how one can define arrays. I think somewhere inside I have to keep doing new int[] but I'm not sure exactly where. You don't have to convert the whole thing, just enough so I can understand how to do it. I would really appreciate it. I would like to use integers instead of characters, by the way. Thanks again // Pieces definition char mArray [7][4][5][5] = { // Square { { {0, 0, 0, 0, 0}, {0, 0, 0, 0, 0}, {0, 0, 2, 1, 0}, {0, 0, 1, 1, 0}, {0, 0, 0, 0, 0} }, { {0, 0, 0, 0, 0}, {0, 0, 0, 0, 0}, {0, 0, 2, 1, 0}, {0, 0, 1, 1, 0}, {0, 0, 0, 0, 0} }, { {0, 0, 0, 0, 0}, {0, 0, 0, 0, 0}, {0, 0, 2, 1, 0}, {0, 0, 1, 1, 0}, {0, 0, 0, 0, 0} }, { {0, 0, 0, 0, 0}, {0, 0, 0, 0, 0}, {0, 0, 2, 1, 0}, {0, 0, 1, 1, 0}, {0, 0, 0, 0, 0} } }, // and so on and so forth, for 6 more };

  Read the article

• c++ connect() keeps returning WSATIMEDOUT over internet but not localy

  - by KaiserJohaan

  Hello, For some reason, my chat application always gets WSATIMEDOUT when trying to connect to another person over the internet. int len_ip = GetWindowTextLength(GetDlgItem(hWnd,ID_EDIT_IP)); char ipBuffer[16]; SendMessage(GetDlgItem(hWnd,ID_EDIT_IP),WM_GETTEXT,16,(LPARAM)ipBuffer); long host_ip = inet_addr(ipBuffer); int initializeConnection(long host_ip, HWND hWnd) { // initialize winsock WSADATA wdata; int result = WSAStartup(MAKEWORD(2,2),&wdata); if (result != 0) { return 0; } // setup socket tcp_sock = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if (tcp_sock == INVALID_SOCKET) { return 0; } // setup socket address SOCKADDR_IN tcp_sock_addr; tcp_sock_addr.sin_family = AF_INET; tcp_sock_addr.sin_port = SERVER_TCP_PORT; tcp_sock_addr.sin_addr.s_addr = host_ip; // connect to server if (connect(tcp_sock,(SOCKADDR*)&tcp_sock_addr,sizeof(tcp_sock_addr)) == SOCKET_ERROR) { return 0; } HRESULT hr = WSAGetLastError(); // set socket in asynchronous mode if (WSAAsyncSelect(tcp_sock,hWnd,SOCKET_TCP, FD_READ | FD_WRITE | FD_CONNECT | FD_CLOSE) == SOCKET_ERROR) { return 0; } return 1; } For some reason it works perfectly fine on local network between computers, but totally screws up over the internet. WSATIMEDOUT is always returned (not connection refused, so its not a port problem). It makes me believe something is wrong with the IP but why on earth can it work on local addresses (like 192.168.2.4) Any ideas? Cheers

  Read the article

• reading a file of unknown length with a function

  - by Faken

  I'm trying to write a short function that will let me quickly read in a file of unknown size and return pointer to the array of data and the length of that array but it seems my code isn't working. What am i doing wrong? int readIn(int* pointer, param parameters, string description) { string fileName = parameters.fileName + " " + description + ".bin"; ifstream readFile; readFile.open(fileName.c_str(), ios::in|ios::binary|ios::ate); int size = readFile.tellg(); int length = size / 4; int* output = new int [length]; readFile.seekg (0, ios::beg); readFile.read(reinterpret_cast<char*>(output), (size)); readFile.close(); pointer = output; // link new array with the pointer return length; } and in the main function: int* testList; int numEntries = readIn(testList, parameters, "test"); I end up with an error saying that my testList variable was used and not initialized. What am i doing wrong?

  Read the article

• What goes into main function?

  - by Woltan

  I am looking for a best practice tip of what goes into the main function of a program using c++. Currently I think two approaches are possible. (Although the "margins" of those approaches can be arbitrarily close to each other) 1: Write a "Master"-class that receives the parameters passed to the main function and handle the complete program in that "Master"-class (Of course you also make use of other classes). Therefore the main function would be reduced to a minimum of lines. #include "MasterClass.h" int main(int args, char* argv[]) { MasterClass MC(args, argv); } 2: Write the "complete" program in the main function making use of user defined objects of course! However there are also global functions involved and the main function can get somewhat large. I am looking for some general guidelines of how to write the main function of a program in c++. I came across this issue by trying to write some unit test for the first approach, which is a little difficult since most of the methods are private. Thx in advance for any help, suggestion, link, ...

  Read the article

• How do you safely wrap a JS string variable in double quote chars?

  - by incombinative

  Obviously when you're creating an actual string literal yourself, you backslash escape the double quote characters yourself. var foo = "baz\"bat"; Just as you would with the handful of other control characters, like linebreaks and backslashes. var bar = "baz\\bat"; but when you already have a variable, and you're wrapping that existing variable in quote characters, there's some confusion. Obviously you have to escape any potential double quote characters that are in the string. (Assuming whatever system you're giving the explicitly quoted string to, needs to be able to parse them correctly. =) var doubleQuoteRe = /\"/g; var quoted = unquoted.replace(escaper, '\\\"'); However from there opinions diverge a little. In particular, according to some you also have to worry about escaping literal backslash characters in the variable. // now say i have a string bar, that has both single backslash character in it, // as well as a double-quote character in it. // the following code ONLY worries about escaping the double quote char. var quoted = bar.replace(doubleQuoteRe, '\\\"'); The above seems fine to me. But is there a problem im not seeing?

  Read the article

• Objective-C ref count and autorelease

  - by turbovince

  Hey guys, suppose the following code: int main (int argc, const char * argv[]) { //[...] Rectangle* myRect = [[Rectangle alloc] init]; Vector2* newOrigin = [[[Vector2 alloc] init] autorelease]; // ref count 1 [newOrigin setX: 50.0f]; [myRect setOrigin: newOrigin]; // ref count 2 [myRect.origin setXY: 25.0f :100.0f]; // ref count goes to 3... why ? [myRect release]; [pool drain]; return 0; } Rectangle's origin is declared as a (retain) synthesized property. Just wondering 2 things: Why does ref count goes to 3 when using the getter accessor of Rectangle's origin? Am I doing something wrong ? With a ref count of 3, I don't understand how this snippet of code cannot leak. Calling release on myRect will make it go down to 2 since I call release on the origin in dealloc(). But then, when does autorelease take effect? Thanks!

  Read the article

• How is an AppDelegate instanciated?

  - by pwny

  I have an iOS application for which I want to create a ViewController programmatically. I started an empty XCode project and modified the main method so it looks like this int main(int argc, char *argv[]) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; int retVal = UIApplicationMain(argc, argv, nil, @"MyAppDelegate_iPad"); [pool release]; return retVal; } The app is a Universal Application, MyAppDelegate_iPad is a subclass of MyAppDelegate, which is a subclass of NSObject <UIApplicationDelegate>. My problem is that the applicationDidFinishLoading method I've overridden in MyAppDelegate_iPad is never called (break point on the first line never hits). The method looks like this -(void) applicationDidFinishLaunching:(UIApplication *)application { window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; if(!window) { [self release]; return; } window.backgroundColor = [UIColor whiteColor]; rootController = [[MyViewController alloc] init]; [window addSubview:rootController.view]; [window makeKeyAndVisible]; [window layoutSubviews]; } I removed the line to link to a nib file from my plist file (I used to get the default "My Universal app on iPad" white screen) and now all that is displayed is a black screen. applicationDidFinishLoading is still not being called. Am I doing something wrong? How should I properly create my AppDelegate instance?

  Read the article

• c# winforms events restore textbox contents on escape

  - by aj3jr

  Using c# in 2008 Express. I have a textbox containing a path. I append a "\" at the end on Leave Event. If the user presses 'Escape' key I want the old contents to be restored. When I type over all the text and press 'Escape' I hear a thump and the old text isn't restored. Here what I have so far ... public string _path; public string _oldPath; this.txtPath.KeyPress += new System.Windows.Forms.KeyPressEventHandler(txtPath_CheckKeys); this.txtPath.Enter +=new EventHandler(txtPath_Enter); this.txtPath.LostFocus += new EventHandler(txtPath_LostFocus); public void txtPath_CheckKeys(object sender, KeyPressEventArgs kpe) { if (kpe.KeyChar == (char)27) { _path = _oldPath; } } public void txtPath_Enter(object sender, EventArgs e) { //AppendSlash(sender, e); _oldPath = _path; } void txtPath_LostFocus(object sender, EventArgs e) { //throw new NotImplementedException(); AppendSlash(sender, e); } public void AppendSlash(object sender, EventArgs e) { //add a slash to the end of the txtPath string on ANY change except a restore this.txtPath.Text += @"\"; } Thanks in advance,

  Read the article

• Converting "A* Search" code from C++ to Java [on hold]

  - by mr5

  Updated! I get this code from this site It's A* Search Algorithm(finding shortest path with heuristics) I modify most of variable names and some if conditions from the original version to satisfy my syntactic taste. It works in C++ (as I can't see any trouble with it) but fails in Java version. Java Code: String findPath(int startX, int startY, int finishX, int finishY) { @SuppressWarnings("unchecked") LinkedList<Node>[] nodeList = (LinkedList<Node>[]) new LinkedList<?>[2]; nodeList[0] = new LinkedList<Node>(); nodeList[1] = new LinkedList<Node>(); Node n0; Node m0; int nlIndex = 0; // queueList index // reset the node maps for(int y = 0;y < ROW_COUNT; ++y) { for(int x = 0;x < COL_COUNT; ++x) { close_nodes_map[y][x] = 0; open_nodes_map[y][x] = 0; } } // create the start node and push into list of open nodes n0 = new Node( startX, startY, 0, 0 ); n0.updatePriority( finishX, finishY ); nodeList[nlIndex].push( n0 ); open_nodes_map[startY][startX] = n0.getPriority(); // mark it on the open nodes map // A* search while( !nodeList[nlIndex].isEmpty() ) { LinkedList<Node> pq = nodeList[nlIndex]; // get the current node w/ the highest priority // from the list of open nodes n0 = new Node( pq.peek().getX(), pq.peek().getY(), pq.peek().getIterCount(), pq.peek().getPriority()); int x = n0.getX(); int y = n0.getY(); nodeList[nlIndex].pop(); // remove the node from the open list open_nodes_map[y][x] = 0; // mark it on the closed nodes map close_nodes_map[y][x] = 1; // quit searching when the goal state is reached //if((*n0).estimate(finishX, finishY) == 0) if( x == finishX && y == finishY ) { // generate the path from finish to start // by following the directions String path = ""; while( !( x == startX && y == startY) ) { int j = dir_map[y][x]; int c = '0' + ( j + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; path = (char)c + path; x += DIR_X[j]; y += DIR_Y[j]; } return path; } // generate moves (child nodes) in all possible directions for(int i = 0; i < Node.DIRECTION_COUNT; ++i) { int xdx = x + DIR_X[i]; int ydy = y + DIR_Y[i]; // boundary check if (!(xdx >= 0 && xdx < COL_COUNT && ydy >= 0 && ydy < ROW_COUNT)) continue; if ( ( gridMap.getData( ydy, xdx ) == GridMap.WALKABLE || gridMap.getData( ydy, xdx ) == GridMap.FINISH) && close_nodes_map[ydy][xdx] != 1 ) { // generate a child node m0 = new Node( xdx, ydy, n0.getIterCount(), n0.getPriority() ); m0.nextLevel( i ); m0.updatePriority( finishX, finishY ); // if it is not in the open list then add into that if( open_nodes_map[ydy][xdx] == 0 ) { open_nodes_map[ydy][xdx] = m0.getPriority(); nodeList[nlIndex].push( m0 ); // mark its parent node direction dir_map[ydy][xdx] = ( i + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; } else if( open_nodes_map[ydy][xdx] > m0.getPriority() ) { // update the priority info open_nodes_map[ydy][xdx] = m0.getPriority(); // update the parent direction info dir_map[ydy][xdx] = ( i + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; // replace the node // by emptying one queueList to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while( !(nodeList[nlIndex].peek().getX() == xdx && nodeList[nlIndex].peek().getY() == ydy ) ) { nodeList[1 - nlIndex].push( nodeList[nlIndex].pop() ); } nodeList[nlIndex].pop(); // remove the wanted node // empty the larger size queueList to the smaller one if( nodeList[nlIndex].size() > nodeList[ 1 - nlIndex ].size() ) nlIndex = 1 - nlIndex; while( !nodeList[nlIndex].isEmpty() ) { nodeList[1 - nlIndex].push( nodeList[nlIndex].pop() ); } nlIndex = 1 - nlIndex; nodeList[nlIndex].push( m0 ); // add the better node instead } } } } return ""; // no route found } Output1: Legends . = PATH ? = START X = FINISH 3,2,1 = OBSTACLES (Misleading path) Output2: Changing these lines: n0 = new Node( a, b, c, d ); m0 = new Node( e, f, g, h ); to n0.set( a, b, c, d ); m0.set( e, f, g, h ); I get (I'm really confused) C++ Code: std::string A_Star::findPath(int startX, int startY, int finishX, int finishY) { typedef std::queue<Node> List_Container; List_Container nodeList[2]; // list of open (not-yet-tried) nodes Node n0; Node m0; int pqIndex = 0; // nodeList index // reset the node maps for(int y = 0;y < ROW_COUNT; ++y) { for(int x = 0;x < COL_COUNT; ++x) { close_nodes_map[y][x] = 0; open_nodes_map[y][x] = 0; } } // create the start node and push into list of open nodes n0 = Node( startX, startY, 0, 0 ); n0.updatePriority( finishX, finishY ); nodeList[pqIndex].push( n0 ); open_nodes_map[startY][startX] = n0.getPriority(); // mark it on the open nodes map // A* search while( !nodeList[pqIndex].empty() ) { List_Container &pq = nodeList[pqIndex]; // get the current node w/ the highest priority // from the list of open nodes n0 = Node( pq.front().getX(), pq.front().getY(), pq.front().getIterCount(), pq.front().getPriority()); int x = n0.getX(); int y = n0.getY(); nodeList[pqIndex].pop(); // remove the node from the open list open_nodes_map[y][x] = 0; // mark it on the closed nodes map close_nodes_map[y][x] = 1; // quit searching when the goal state is reached //if((*n0).estimate(finishX, finishY) == 0) if( x == finishX && y == finishY ) { // generate the path from finish to start // by following the directions std::string path = ""; while( !( x == startX && y == startY) ) { int j = dir_map[y][x]; char c = '0' + ( j + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; path = c + path; x += DIR_X[j]; y += DIR_Y[j]; } return path; } // generate moves (child nodes) in all possible directions for(int i = 0; i < DIRECTION_COUNT; ++i) { int xdx = x + DIR_X[i]; int ydy = y + DIR_Y[i]; // boundary check if (!( xdx >= 0 && xdx < COL_COUNT && ydy >= 0 && ydy < ROW_COUNT)) continue; if ( ( pGrid->getData(ydy,xdx) == WALKABLE || pGrid->getData(ydy, xdx) == FINISH) && close_nodes_map[ydy][xdx] != 1 ) { // generate a child node m0 = Node( xdx, ydy, n0.getIterCount(), n0.getPriority() ); m0.nextLevel( i ); m0.updatePriority( finishX, finishY ); // if it is not in the open list then add into that if( open_nodes_map[ydy][xdx] == 0 ) { open_nodes_map[ydy][xdx] = m0.getPriority(); nodeList[pqIndex].push( m0 ); // mark its parent node direction dir_map[ydy][xdx] = ( i + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; } else if( open_nodes_map[ydy][xdx] > m0.getPriority() ) { // update the priority info open_nodes_map[ydy][xdx] = m0.getPriority(); // update the parent direction info dir_map[ydy][xdx] = ( i + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; // replace the node // by emptying one nodeList to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while ( !( nodeList[pqIndex].front().getX() == xdx && nodeList[pqIndex].front().getY() == ydy ) ) { nodeList[1 - pqIndex].push( nodeList[pqIndex].front() ); nodeList[pqIndex].pop(); } nodeList[pqIndex].pop(); // remove the wanted node // empty the larger size nodeList to the smaller one if( nodeList[pqIndex].size() > nodeList[ 1 - pqIndex ].size() ) pqIndex = 1 - pqIndex; while( !nodeList[pqIndex].empty() ) { nodeList[1-pqIndex].push(nodeList[pqIndex].front()); nodeList[pqIndex].pop(); } pqIndex = 1 - pqIndex; nodeList[pqIndex].push( m0 ); // add the better node instead } } } } return ""; // no route found } Output: Legends . = PATH ? = START X = FINISH 3,2,1 = OBSTACLES (Just right) From what I read about Java's documentation, I came up with the conclusion: C++'s std::queue<T>::front() == Java's LinkedList<T>.peek() Java's LinkedList<T>.pop() == C++'s std::queue<T>::front() + std::queue<T>::pop() What might I be missing in my Java version? In what way does it became different algorithmically from the C++ version?

  Read the article

• F# ref-mutable vars vs object fields

  - by rwallace

  I'm writing a parser in F#, and it needs to be as fast as possible (I'm hoping to parse a 100 MB file in less than a minute). As normal, it uses mutable variables to store the next available character and the next available token (i.e. both the lexer and the parser proper use one unit of lookahead). My current partial implementation uses local variables for these. Since closure variables can't be mutable (anyone know the reason for this?) I've declared them as ref: let rec read file includepath = let c = ref ' ' let k = ref NONE let sb = new StringBuilder() use stream = File.OpenText file let readc() = c := stream.Read() |> char // etc I assume this has some overhead (not much, I know, but I'm trying for maximum speed here), and it's a little inelegant. The most obvious alternative would be to create a parser class object and have the mutable variables be fields in it. Does anyone know which is likely to be faster? Is there any consensus on which is considered better/more idiomatic style? Is there another option I'm missing?

  Read the article

• Getting functions of inherited functions to be called

  - by wrongusername

  Let's say I have a base class Animal from which a class Cow inherits, and a Barn class containing an Animal vector, and let's say the Animal class has a virtual function scream(), which Cow overrides. With the following code: Animal.h #ifndef _ANIMAL_H #define _ANIMAL_H #include <iostream> using namespace std; class Animal { public: Animal() {}; virtual void scream() {cout << "aaaAAAAAAAAAAGHHHHHHHHHH!!! ahhh..." << endl;} }; #endif /* _ANIMAL_H */ Cow.h #ifndef _COW_H #define _COW_H #include "Animal.h" class Cow: public Animal { public: Cow() {} void scream() {cout << "MOOooooOOOOOOOO!!!" << endl;} }; #endif /* _COW_H */ Barn.h #ifndef _BARN_H #define _BARN_H #include "Animal.h" #include <vector> class Barn { std::vector<Animal> animals; public: Barn() {} void insertAnimal(Animal animal) {animals.push_back(animal);} void tortureAnimals() { for(int a = 0; a < animals.size(); a++) animals[a].scream(); } }; #endif /* _BARN_H */ and finally main.cpp #include <stdlib.h> #include "Barn.h" #include "Cow.h" #include "Chicken.h" /* * */ int main(int argc, char** argv) { Barn barn; barn.insertAnimal(Cow()); barn.tortureAnimals(); return (EXIT_SUCCESS); } I get this output: aaaAAAAAAAAAAGHHHHHHHHHH!!! ahhh... How should I code this to get MOOooooOOOOOOOO!!! (and whatever other classes inheriting Animal wants scream() to be) instead?

  Read the article

• Boost program will not working on Linux

  - by Martin Lauridsen

  Hi SOF, I have this program which uses Boost::Asio for sockets. I pretty much altered some code from the Boost examples. The program compiles and runs just like it should on Windows in VS. However, when I compile the program on Linux and run it, I get a Segmentation fault. I posted the code here The command I use to compile it is this: c++ -I/appl/htopopt/Linux_x86_64/NTL-5.4.2/include -I/appl/htopopt/Linux_x86_64/boost_1_43_0/include mpqs.cpp mpqs_polynomial.cpp mpqs_host.cpp -o mpqs_host -L/appl/htopopt/Linux_x86_64/NTL-5.4.2/lib -lntl -L/appl/htopopt/Linux_x86_64/gmp-4.2.1/lib -lgmp -lm -L/appl/htopopt/Linux_x86_64/boost_1_43_0/lib -lboost_system -lboost_thread -static -lpthread By commenting out code, I have found out that I get the Segmentation fault due to the following line: boost::asio::io_service io_service; Can anyone provide any assistance, as to what may be the problem (and the solution)? Thanks! Edit: I tried changing the program to a minimal example, using no other libraries or headers, just boost/asio.hpp: #define DEBUG 0 #include <boost/asio.hpp> int main(int argc, char* argv[]) { boost::asio::io_service io_service; return 0; } I also removed other library inclusions and linking on compilation, however this minimal example still gives me a segmentation fault.

  Read the article

• How to remove the first and last character from a file using batch script?

  - by infant programmer

  This is my input file content which I am using to copy to the output file. #sdfs|dfasf|sdfs| sdfs|df!@$%%*&!sdffs| sasdfasfa|dfsdf|#sdfs| What I need to do is to omit the first character '#' and last character '|' in the output file. So the output will be, sdfs|dfasf|sdfs| sdfs|df!@$%%*&!sdffs| sasdfasfa|dfsdf|#sdfs Batch script is new to me, but I tried my best and tried these codes, :: drop first and last char @echo off > xyz.txt & setLocal EnableDelayedExpansion for /f "tokens=* delims=" %%a in (E:\abc1.txt) do ( set str=%%a set str=!str:~1! echo !str!>> xyz.txt ) and @echo off > xyz.txt setLocal EnableDelayedExpansion for /f "tokens=1,2 delims= " %%a in (E:\abc1.txt) do ( set /a N+=1 if !N! gtr 2 ( echo %%a >> xyz.txt ) else ( set str=%%a set str=!str:#=! echo !str! >> xyz.txt ) ) As you can see they are not able to produce the required output.

  Read the article

• Template Child Class Overriding a Parent Class's Virtual Function

  - by user334066

  The below code compiles with gcc v4.3.3 and the templated child class seems to be overriding a virtual function in the parent, but doesn't that break the rule that you cannot have a virtual template function? Or is something else happening that I don't understand? class BaseClass { public: virtual void Func(int var) { std::cout<<"Base int "<<var<<std::endl; } virtual void Func(double var) { std::cout<<"Base double "<<var<<std::endl; } }; template <class TT> class TemplateClass : public BaseClass { public: using BaseClass::Func; virtual void Func(TT var) { std::cout<<"Child TT "<<var<<std::endl; } }; int main(int argc, char **argv) { BaseClass a; TemplateClass<int> b; BaseClass *c = new TemplateClass<int>; int intVar = 3; double doubleVar = 5.5; a.Func(intVar); a.Func(doubleVar); b.Func(intVar); b.Func(doubleVar); c->Func(intVar); c->Func(doubleVar); delete c; } This then outputs: Base int 3 Base double 5.5 Child TT 3 Base double 5.5 Child TT 3 Base double 5.5 as I hoped, but I'm not sure why it works.

  Read the article

• Why won't this work; opencv Mat_<float>

  - by user1371674

  I can't seem to get this to work. I'm trying to get the pixel value of an image but first need to change the color of the image, but since I cannot use int or just Mat because the values are not whole numbers, I have to use and because of that errors pop up when I try to run this on the cmd. int main(int argc, char **argv) { Mat img = imread(argv[1]); ofstream myfile; Mat_<float> MatBlue = img; int rows1 = MatBlue.rows; int cols1 = MatBlue.cols; for(int x = 0; x < cols1; x++) { for(int y = 0; y < rows1; y++) { float val = MatBlue.at<cv::Vec3b>(y, x)[1]; MatBlue.at<cv::Vec3b>(y, x)[0] = val + 1; } } }

  Read the article

• How can I hardcode input with the "select" system call in C?

  - by Archer

  If I understand this system call "select" correctly, it will loop waiting for user input from the keyboard or from an outside server. Every time I call "message_loop", I'm going to type in the same few lines of input each time. Is there a way to hard code this in so I don't have to type it in each time? void message_loop(FILE* fpin, FILE* fpout, Socket sock) { fd_set readfds, readfds_bak ; int in, max_fd, n, ret ; char buf[MAXMESG]; in = fileno(fpin) ; FD_ZERO(&readfds) ; FD_SET(in, &readfds) ; FD_SET(sock.socketfd, &readfds) ; readfds_bak = readfds ; max_fd = ((in > sock.socketfd) ? in : sock.socketfd) + 1 ; while(1){ readfds = readfds_bak ; /* select function */ if((ret = select(max_fd, &readfds, NULL, NULL, NULL)) < 0){ perror("select") ; break ; } else if (ret != 0) { if(FD_ISSET(in, &readfds)){ /* keyboard input */ fgets(buf, MAXMESG, fpin) ; if(send_message(buf, sock) == -1) break ; } if(FD_ISSET(sock.socketfd, &readfds)){ /* messages from server */ n = receive_message(buf, MAXMESG, &sock) ; if(n == -1) break ; else if(n > 0){ fputs(buf, fpout) ; fputc('\n', fpout) ; } fflush(stdout) ; } } } }

  Read the article

• Strange Access Denied warning when running the simplest C++ program.

  - by DaveJohnston

  I am just starting to learn C++ (coming from a Java background) and I have come across something that I can't explain. I am working through the C++ Primer book and doing the exercises. Every time I get to a new exercise I create a new .cpp file and set it up with the main method (and any includes I think I will need) e.g.: #include <list> #include <vector> int main(int argc, char **args) { } and just to make sure I go to the command prompt and compile and run: g++ whatever.cpp a.exe Normally this works just fine and I start working on the exercise, but I just did it and got a strange error. It compiles fine, but when I run it it says Access Denied and AVG pops up telling me that a threat has been detected 'Trojan Horse Generic 17.CKZT'. I tried compiling again using the Microsoft Compiler (cl.exe) and it runs fines. So I went back, and added: #include <iostream> compiled using g++ and ran. This time it worked fine. So can anyone tell me why AVG would report an empty main method as a trojan horse but if the iostream header is included it doesn't?

  Read the article

• Scanning, Checking, Converting, Copying values ... How to ? -- C --

  - by ZaZu

  Hi there, Its been a while now and im still trying to get a certain code to work. I asked some question about different commands etc. before, but now I hope this is the final one (combining all questions in one code). I basically want to : *Scan an input (should be character ? ) *Check if its a number *If not, return error *Convert that character into a float number *Copy the value to another variable ( I called it imp here) Here is what I came up with : #include<stdio.h> #include<stdlib.h> #include<ctype.h> main(){ int digits; float imp=0; int alpha; do{ printf("Enter input\n\n"); scanf("\n%c",&alpha); digits=isdigit(alpha); if(digits==0){ printf("error\n\n"); } imp=atof(alpha); }while(digits==0); } The problem is this code does not work at all ... It gives me that atof must be of a const char and whenever I try changing it around, it just keeps failing. I am frustrated and forced to ask here, because I believe I have tried alot and I keep failing, but I wont be relieved until I get it to work xD So I really need your help guys. Please tell me why isnt this code working, what am I doing wrong ? I am still learning C and really appreciate your help :)

  Read the article

• Using Relative Paths to Load Resources in Cocoa/C++

  - by moka

  I am currently working directly with Cocoa for the first time to built a screen saver. Now I came across a problem when trying to load resources from within the .saver bundle. I basically have a small C++ wrapper class to load .exr files using freeImage. This works as long as I use absoulte paths, but that's not very useful, is it? So, basically, I tried everything: putting the .exr file at the level of the .saver bundle itself, inside the bundles Resources folder, and so on. Then I simply tried to load the .exr like this, but without success: particleTex = [self loadExrTexture:@"ball.exr"]; I also tried making it go to the .saver bundles location like this: particleTex = [self loadExrTexture:@"../../../ball.exr"]; ...to maybe load the .exr from that location, but without success. I then came across this: NSString * path = [[NSBundle mainBundle] pathForResource:@"ball" ofType:@"exr"]; const char * pChar = [path UTF8String]; ...which seems to be a common way to find resources in Cocoa, but for some reason it's empty in my case. Any ideas about that? I really tried out anything that came to my mind without success so I would be glad about some input!

  Read the article

• C++: Maybe you know this fitfall?

  - by Martijn Courteaux

  Hi, I'm developing a game. I have a header GameSystem (just methods like the game loop, no class) with two variables: int mouseX and int mouseY. These are updated in my game loop. Now I want to access them from Game.cpp file (a class built by a header-file and the source-file). So, I #include "GameSystem.h" in Game.h. After doing this I get a lot of compile errors. When I remove the include he says of course: Game.cpp:33: error: ‘mouseX’ was not declared in this scope Game.cpp:34: error: ‘mouseY’ was not declared in this scope Where I want to access mouseX and mouseY. All my .h files have Header Guards, generated by Eclipse. I'm using SDL and if I remove the lines that wants to access the variables, everything compiles and run perfectly (*). I hope you can help me... This is the error-log when I #include "GameSystem.h" (All the code he is refering to works, like explained by the (*)): In file included from ../trunk/source/domein/Game.h:14, from ../trunk/source/domein/Game.cpp:8: ../trunk/source/domein/GameSystem.h:30: error: expected constructor, destructor, or type conversion before ‘*’ token ../trunk/source/domein/GameSystem.h:46: error: variable or field ‘InitGame’ declared void ../trunk/source/domein/GameSystem.h:46: error: ‘Game’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: ‘g’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘char’ ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘bool’ ../trunk/source/domein/FPS.h:46: warning: ‘void FPS_SleepMilliseconds(int)’ defined but not used This is the code which try to access the two variables: SDL_Rect pointer; pointer.x = mouseX; pointer.y = mouseY; pointer.w = 3; pointer.h = 3; SDL_FillRect(buffer, &pointer, 0xFF0000);

  Read the article

< Previous Page | 212 213 214 215 216 217 218 219 220 221 222 223  | Next Page >