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  • How to throw meaningful data in exceptions ?

    - by ZeroCool
    I would like to throw exceptions with meaningful explanation ! I thought of using variable arguments worked fine but lately I figured out it's impossible to extend the class in order to implement other exception types. So I figured out using an std::ostreamstring as a an internal buffer to deal with formatting ... but doesn't compile! I guess it has something to deal with copy constructors. Anyhow here is my piece of code: class Exception: public std::exception { public: Exception(const char *fmt, ...); Exception(const char *fname, const char *funcname, int line, const char *fmt, ...); //std::ostringstream &Get() { return os_ ; } ~Exception() throw(); virtual const char *what() const throw(); protected: char err_msg_[ERRBUFSIZ]; //std::ostringstream os_; }; The variable argumens constructor can't be inherited from! this is why I thought of std::ostringstream! Any advice on how to implement such approach ?

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  • Problem with reading and writing to binary file in C++

    - by Reem
    I need to make a file that contains "name" which is a string -array of char- and "data" which is array of bytes -array of char in C++- but the first problem I faced is how to separate the "name" from the "data"? newline character could work in this case (assuming that I don't have "\n" in the name) but I could have special characters in the "data" part so there's no way to know when it ends so I'm putting an int value in the file before the data which has the size of the "data"! I tried to do this with code as follow: if((fp = fopen("file.bin","wb")) == NULL) { return false; } char buffer[] = "first data\n"; fwrite( buffer ,1,sizeof(buffer),fp ); int number[1]; number[0]=10; fwrite( number ,1,1, fp ); char data[] = "1234567890"; fwrite( data , 1, number[0], fp ); fclose(fp); but I didn't know if the "int" part was right, so I tried many other codes including this one: char buffer[] = "first data\n"; fwrite( buffer ,1,sizeof(buffer),fp ); int size=10; fwrite( &size ,sizeof size,1, fp ); char data[] = "1234567890"; fwrite( data , 1, number[0], fp ); I see 4 "NULL" characters in the file when I open it instead of seeing an integer. Is that normal? The other problem I'm facing is reading that again from the file! The code I tried to read didn't work at all :( I tried it with "fread" but I'm not sure if I should use "fseek" with it or it just read the other character after it. Forgive me but I'm a beginner :(

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  • Aliasing `T*` with `char*` is allowed. Is it also allowed the other way around?

    - by StackedCrooked
    Note: This question has been renamed and reduced to make it more focused and readable. Most of the comments refer to the old text. According to the standard objects of different type may not share the same memory location. So this would not be legal: int i = 0; short * s = reinterpret_cast<short*>(&i); // BAD! The standard however allows an exception to this rule: any object may be accessed through a pointer to char or unsigned char: int i = 0; char * c = reinterpret_cast<char*>(&i); // OK However, it is not clear to me if this is also allowed the other way around. For example: char * c = read_socket(...); unsigned * u = reinterpret_cast<unsigned*>(c); // huh? Summary of the answers The answer is NO for two reasons: You an only access an existing object as char*. There is no object in my sample code, only a byte buffer. The pointer address may not have the right alignment for the target object. In that case dereferencing it would result in undefined behavior. On the Intel and AMD platforms it will result performance overhead. On ARM it will trigger a CPU trap and your program will be terminated! This is a simplified explanation. For more detailed information see answers by @Luc Danton, @Cheers and hth. - Alf and @David Rodríguez.

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  • Beginner error in CUDA

    - by Dimitri
    Hi folks, first all i want to wish you a merry christmas. I am writing a small program in CUDA and i have the following errors : contraste.cu(167): error: calling a host function from a __device__/__global__ function is not allowed I don't understand why. Can you please help me and show me my errors. It seems that my program is correct. Here is a the bunch of code causing the problems : __global__ void kernel_contraste(float power, unsigned char tab_in[], unsigned char tab_out[], int nbl, int nbc) { int x = threadIdx.x; printf("I am the thread %d\n", x); } Part of my main program : unsigned char *dimg, *dimg_res; ..... cudaMalloc((void **)dimg, h * w * sizeof(char)); cudaMemcpy(dimg, r.data, h*w*sizeof(char), cudaMemcpyHostToDevice); cudaMalloc((void **)dimg_res, h*w*sizeof(char)); dim3 nbThreadparBloc(256); dim3 numblocs(1); kernel_contraste<<<numblocs, nbThreadparBloc >>>(puissance, dimg, dimg_res, h, w); cudaThreadSynchronize(); ..... cudaFree(dimg); cudaFree(dimg_res); The line 167 is the line where i call the printf in function kernel_contraste. For information, this program takes an image as an input( a sun Rasterfile ) and a power then it calculates the contraste of that image. Thanks !!

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  • C++ Recursive function that reverses the order of an array's indexes between two bounds

    - by CPT Kirk
    I am trying to write a recursive function that has three arguments; an array and two array indexes. The function should reverse the order of the values between the two indexes. I would like to understand what is happening instead of just being told an answer. Here is my code so far: #include <iostream> using namespace std; char switchAroo(char a[], int b1, int b2); int main() { char a[6] {'A', 'B', 'C', 'D', 'E', '\0'}; cout << a; switchAroo(a, 2, 5); return 0; } char switchAroo(char a [], int b1, int b2) { char temp; if (b1 == b2) cout << "The array after switchAroo is " << a << endl; else { temp = a[b1]; a[b1] = a[b2]; a[b2] = temp; b1++; b2--; return switchAroo(a, b1, b2); } } I am getting the following warning code: warning C4715: 'switchAroo' : not all control paths return a value Any help would be greatly appreciated.

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  • why no implicit conversion from pointer to reference to const pointer.

    - by user316606
    I'll illustrate my question with code: #include <iostream> void PrintInt(const unsigned char*& ptr) { int data = 0; ::memcpy(&data, ptr, sizeof(data)); // advance the pointer reference. ptr += sizeof(data); std::cout << std::hex << data << " " << std::endl; } int main(int, char**) { unsigned char buffer[] = { 0x11, 0x11, 0x11, 0x11, 0x22, 0x22, 0x22, 0x22, }; /* const */ unsigned char* ptr = buffer; PrintInt(ptr); // error C2664: ... PrintInt(ptr); // error C2664: ... return 0; } When I run this code (in VS2008) I get this: error C2664: 'PrintInt' : cannot convert parameter 1 from 'unsigned char *' to 'const unsigned char *&'. If I uncomment the "const" comment it works fine. However shouldn't pointer implicitly convert into const pointer and then reference be taken? Am I wrong in expecting this to work? Thanks!

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  • Counting the number of occurrences of characters in an array

    - by Anthony Pittelli
    This is what I have but it is not working, this is confusing for me. If you scroll down I commented on someones post the exact problem I am having and what I am trying to do. I was thinking maybe the problem is my code to generate the random characters: public void add (char fromChar, char toChar){ Random r = new Random(); //creates a random object int randInt; for (int i=0; i<charArray.length; i++){ randInt = r.nextInt((toChar-fromChar) +1); charArray[i] = (char) randInt; //casts these integers as characters } }//end add public int[] countLetters() { int[] count = new int[26]; char current; for (int b = 0; b <= 26; b++) { for (int i = 97; i <= 123; i++) { char a = (char) i; for (int ch = 0; ch < charArray.length; ch++) { current = charArray[ch]; if (current == a) { count[b]++; } } } } return count; }

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  • multiple calls to realloc() seems to cause a heap corruption..

    - by Windindeed
    What's the problem with this code? It crashes every time. One time it's a failed assertion "_ASSERTE(_CrtIsValidHeapPointer(pUserData));", other times it is just a "heap corrpuption" error. Changing the buffer size affects this issue in some strange ways - sometimes it crashes on the "realloc", and other times on the "free". I have debugged this code many times, and there is nothing abnormal regarding the pointers. char buf[2000]; char *data = (char*)malloc(sizeof(buf)); unsigned int size = sizeof(buf); for (unsigned int i = 0; i < 5; ++i) { char *ptr = data + size; size += sizeof(buf); char *tmp = (char*)realloc(data, size); if (!tmp) { std::cout << "Oh no.."; break; } data = tmp; memcpy(ptr, buf, sizeof(buf)); } free(data); Thanks!

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  • how to change the image on click from database

    - by iosdev
    In my application i having multiple image in sq lite database,Since i want to change to the next image on button click,Here my code, -(void)Readthesqlitefile:(NSInteger *)sno { sqlite3 *database;//database object NSString *docpath=[self doccumentspath];//get sqlite path const char *ch=[docpath UTF8String];//string to constant char UTF8string main part to connect DB if (sqlite3_open(ch, &database)==SQLITE_OK) { const char *chstmt="SELECT * FROM animal where rowid= = %d",sno; sqlite3_stmt *sqlstmt;//to execute the above statement if (sqlite3_prepare_v2(database, chstmt, -1, &sqlstmt, NULL)==SQLITE_OK) { while (sqlite3_step(sqlstmt)==SQLITE_ROW) { const char *Bname=(char *)sqlite3_column_text(sqlstmt, 0); //converting const char to nsstring NSString *Bndname=[NSString stringWithFormat:@"%s",Bname]; NSLog(@"Brand Names=%@",Bndname); lb1.text=[NSString stringWithFormat:Bndname]; NSUInteger legnt=sqlite3_column_bytes(sqlstmt, 1); if (legnt>0) { NSData *dt=[NSData dataWithBytes:sqlite3_column_blob(sqlstmt, 1) length:legnt]; clsimg=[UIImage imageWithData:dt];//converting data to image imager.image=clsimg; } else { clsimg=nil; } } } sqlite3_finalize(sqlstmt); } sqlite3_close(database); } Button click function -(IBAction)changenext { int j; for (j=1; j<10; j++) { [self Readthesqlitefile:j]; } } its is not working pls help me to solve it out?

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  • problem using fprintf

    - by shiran bar
    I'm trying to print to a text file numerous variables yet it doesn't work. I checked and verified that i write it in the correct syntax. I also checked the return value and it's positive therefore i know it did write to the file, however when i open the file it's empty. I would be happy for some help. This is the code: I initiate DynsaleDayPtr in the main: FILE* DynsaleDayPtr = CreateTextFiles("sale_day.txt"); Create function: FILE* CreateTextFiles (char* fileName) { FILE* saleFilePtr=NULL; if((saleFilePtr=fopen(fileName,"a+"))==NULL) printf("File couldn't be opened\n"); return saleFilePtr; } The call to the function TextAddSale is done from a function that is called in the main: TextAddSale(DynSaleDayPtr,dynNumOfRecords); Bool TextAddSale (FILE* DynsaleDayPtr, int* dynNumOfRecords) { char id[6]; char name [50]; char priceChar[20]; char* tmp = NULL; int price=-1; DynamicRecord * newRec=NULL; scanf("%s%s%s",id,name,priceChar); newRec = (DynamicRecord *)malloc(sizeof(DynamicRecord)); if (newRec == NULL) return False; tmp = (char*)malloc(strlen(name)+1); if (tmp == NULL) { free (newRec); return False; } strcpy(tmp,name); newRec->productName = tmp; strcpy(newRec->productId, id); newRec->productPrice=atoi (priceChar); if (fprintf(DynsaleDayPtr,"%d %s %s %d", strlen(newRec->productName), newRec->productId, newRec->productName, newRec->productPrice)>0) { *dynNumOfRecords=(*dynNumOfRecords)+1; return True; } } thanks!

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  • C++ Template Classes and Copy Construction

    - by themoondothshine
    Is there any way I can construct an new object from the given object if the template parameters of both objects are identical at run-time? For example: I have a template class with the declaration: template<typename _Type1, typename _Type2> class Object; Next, I have two instantiations of the template: template class Object<char, int>; template class Object<wchar_t, wint_t>; Now, I want to write a member function such as: template<typename _Type1, typename _Type2> Object<char, int> Object<_Type1, _Type2>::toCharObject() { if(__gnu_cxx::__are_same<_Type1, char>::__value) return *this; else { //Perform some kind of conversion and return an Object<char, int> } } I have tried a couple of techniques, such as using __gnu_cxx::__enable_if<__gnu_cxx::__are_same<_Type1, char>::__value, _Type1>::__type in a copy constructor for the Oject class, but I keep running into the error: error: conversion from ‘Object<wchar_t, wint_t>’ to non-scalar type ‘Object<char, int>’ requested Is there no way I can do this? Any help will be greatly appreciated!

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  • Graphics module: Am I going the right way?

    - by Paul
    I'm trying to write the graphics module of my engine. That is, this part of the code only provides an interface through which to load images, fonts, etc and draw them on the screen. It is also a wrapper for the library I'm using (SDL in this case). Here are the interfaces for my Image, Font and GraphicsRenderer classes. Please tell me if I'm going the right way. Image class Image { public: Image(); Image(const Image& other); Image(const char* file); ~Image(); bool load(const char* file); void free(); bool isLoaded() const; Image& operator=(const Image& other); private: friend class GraphicsRenderer; void* data_; }; Font class Font { public: Font(); Font(const Font& other); Font(const char* file, int ptsize); ~Font(); void load(const char* file, int ptsize); void free(); bool isLoaded() const; Font& operator=(const Font& other); private: friend class GraphicsRenderer; void* data_; }; GrapphicsRenderer class GraphicsRenderer { public: static GraphicsRenderer* Instance(); void blitImage(const Image& img, int x, int y); void blitText(const char* string, const Font& font, int x, int y); void render(); protected: GraphicsRenderer(); GraphicsRenderer(const GraphicsRenderer& other); GraphicsRenderer& operator=(const GraphicsRenderer& other); ~GraphicsRenderer(); private: void* screen_; bool initialize(); void finalize(); };

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  • Can I get a C++ Compiler to instantiate objects at compile time

    - by gam3
    I am writing some code that has a very large number of reasonably simple objects and I would like them the be created at compile time. I would think that a compiler would be able to do this, but I have not been able to figure out how. In C I could do the the following: #include <stdio.h> typedef struct data_s { int a; int b; char *c; } info; info list[] = { 1, 2, "a", 3, 4, "b", }; main() { int i; for (i = 0; i < sizeof(list)/sizeof(*list); i++) { printf("%d %s\n", i, list[i].c); } } Using #C++* each object has it constructor called rather than just being layed out in memory. #include <iostream> using std::cout; using std::endl; class Info { const int a; const int b; const char *c; public: Info(const int, const int, const char *); const int get_a() { return a; }; const int get_b() { return b; }; const char *get_c() const { return c; }; }; Info::Info(const int a, const int b, const char *c) : a(a), b(b), c(c) {}; Info list[] = { Info(1, 2, "a"), Info(3, 4, "b"), }; main() { for (int i = 0; i < sizeof(list)/sizeof(*list); i++) { cout << i << " " << list[i].get_c() << endl; } } I just don't see what information is not available for the compiler to completely instantiate these objects at compile time, so I assume I am missing something.

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  • Choosing a VS project type (C++)

    - by typoknig
    Hi all, I do not use C++ much (I try to stick to the easier stuff like Java and VB.NET), but the lately I have not had a choice. When I am picking a project type in VS for some C++ source I download, what project type should I pick? I had just been sticking with Win32 Console Applications, but I just downloaded some code (below) that will not work right even when it compiles with out errors. I have tried to use a CLR Console Application and an empty project too, and have changed many variables along the way, but I cannot get this code to work. I noticed that this code does not have "int main()" at its beginning, does that have something to do with it? Anyways, here is the code, got it from here: /* Demo of modified Lucas-Kanade optical flow algorithm. See the printf below */ #ifdef _CH_ #pragma package <opencv> #endif #ifndef _EiC #include "cv.h" #include "highgui.h" #include <stdio.h> #include <ctype.h> #endif #include <windows.h> #define FULL_IMAGE_AS_OUTPUT_FILE #define cvMirror cvFlip //IplImage *image = 0, *grey = 0, *prev_grey = 0, *pyramid = 0, *prev_pyramid = 0, *swap_temp; IplImage **buf = 0; IplImage *image1 = 0; IplImage *imageCopy=0; IplImage *image = 0; int win_size = 10; const int MAX_COUNT = 500; CvPoint2D32f* points[2] = {0,0}, *swap_points; char* status = 0; //int count = 0; //int need_to_init = 0; //int night_mode = 0; int flags = 0; //int add_remove_pt = 0; bool bLButtonDown = false; //bool bstopLoop = false; CvPoint pt, pt1,pt2; //IplImage* img1; FILE* FileDest; char* strImageDir = "E:\\Projects\\TSCreator\\Images"; char* strItemName = "b"; int imageCount=0; int bFirstFace = 1; // flag for first face int mode = 1; // Mode 1 - Haar Traing Sample Creation, 2 - HMM sample creation, Mode = 3 - Both Harr and HMM. //int startImgeNo = 1; bool isEqualRation = false; //Weidth to height ratio is equal //Selected Image data IplImage *selectedImage = 0; int selectedX = 0, selectedY = 0, currentImageNo = 0, selectedWidth = 0, selectedHeight= 0; CvRect selectedROI; void saveFroHarrTraining(IplImage *src, int x, int y, int width, int height, int imageCount); void saveForHMMTraining(IplImage *src, CvRect roi,int imageCount); // Code for draw ROI Cropping Image void on_mouse( int event, int x, int y, int flags, void* param ) { char f[200]; CvRect reg; if( !image ) return; if( event == CV_EVENT_LBUTTONDOWN ) { bLButtonDown = true; pt1.x = x; pt1.y = y; } else if ( event == CV_EVENT_MOUSEMOVE ) //Draw the selected area rectangle { pt2.x = x; pt2.y = y; if(bLButtonDown) { if( !image1 ) { /* allocate all the buffers */ image1 = cvCreateImage( cvGetSize(image), 8, 3 ); image1->origin = image->origin; points[0] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); points[1] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); status = (char*)cvAlloc(MAX_COUNT); flags = 0; } cvCopy( image, image1, 0 ); //Equal Weight-Height Ratio if(isEqualRation) { pt2.y = pt1.y + (pt2.x-pt1.x); } //Max Height and Width is the image width and height if(pt2.x>image->width) { pt2.x = image->width; } if(pt2.y>image->height) { pt2.y = image->height; } CvPoint InnerPt1 = pt1; CvPoint InnerPt2 = pt2; if ( InnerPt1.x > InnerPt2.x) { int tempX = InnerPt1.x; InnerPt1.x = InnerPt2.x; InnerPt2.x = tempX; } if ( pt2.y < InnerPt1.y ) { int tempY = InnerPt1.y; InnerPt1.y = InnerPt2.y; InnerPt2.y = tempY; } InnerPt1.y = image->height - InnerPt1.y; InnerPt2.y = image->height - InnerPt2.y; CvFont font; double hScale=1.0; double vScale=1.0; int lineWidth=1; cvInitFont(&font,CV_FONT_HERSHEY_SIMPLEX|CV_FONT_ITALIC, hScale,vScale,0,lineWidth); char size [200]; reg.x = pt1.x; reg.y = image->height - pt2.y; reg.height = abs (pt2.y - pt1.y); reg.width = InnerPt2.x -InnerPt1.x; //print width and heght of the selected reagion sprintf(size, "(%dx%d)",reg.width, reg.height); cvPutText (image1,size,cvPoint(10,10), &font, cvScalar(255,255,0)); cvRectangle(image1, InnerPt1, InnerPt2, CV_RGB(255,0,0), 1); //Mark Selected Reagion selectedImage = image; selectedX = pt1.x; selectedY = pt1.y; selectedWidth = reg.width; selectedHeight = reg.height; selectedROI = reg; //Show the modified image cvShowImage("HMM-Harr Positive Image Creator",image1); } } else if ( event == CV_EVENT_LBUTTONUP ) { bLButtonDown = false; // pt2.x = x; // pt2.y = y; // // if ( pt1.x > pt2.x) // { // int tempX = pt1.x; // pt1.x = pt2.x; // pt2.x = tempX; // } // // if ( pt2.y < pt1.y ) // { // int tempY = pt1.y; // pt1.y = pt2.y; // pt2.y = tempY; // // } // //reg.x = pt1.x; //reg.y = image->height - pt2.y; // //reg.height = abs (pt2.y - pt1.y); ////reg.width = reg.height/3; //reg.width = pt2.x -pt1.x; ////reg.height = (2 * reg.width)/3; #ifdef FULL_IMAGE_AS_OUTPUT_FILE CvRect FullImageRect; FullImageRect.x = 0; FullImageRect.y = 0; FullImageRect.width = image->width; FullImageRect.height = image->height; IplImage *regionFullImage =0; regionFullImage = cvCreateImage(cvSize (FullImageRect.width, FullImageRect.height), image->depth, image->nChannels); image->roi = NULL; //cvSetImageROI (image, FullImageRect); //cvCopy (image, regionFullImage, 0); #else IplImage *region =0; region = cvCreateImage(cvSize (reg.width, reg.height), image1->depth, image1->nChannels); image->roi = NULL; cvSetImageROI (image1, reg); cvCopy (image1, region, 0); #endif //cvNamedWindow("Result", CV_WINDOW_AUTOSIZE); //selectedImage = image; //selectedX = pt1.x; //selectedY = pt1.y; //selectedWidth = reg.width; //selectedHeight = reg.height; ////currentImageNo = startImgeNo; //selectedROI = reg; /*if(mode == 1) { saveFroHarrTraining(image,pt1.x,pt1.y,reg.width,reg.height,startImgeNo); } else if(mode == 2) { saveForHMMTraining(image,reg,startImgeNo); } else if(mode ==3) { saveFroHarrTraining(image,pt1.x,pt1.y,reg.width,reg.height,startImgeNo); saveForHMMTraining(image,reg,startImgeNo); } else { printf("Invalid mode."); } startImgeNo++;*/ } } /* Save popsitive samples for Harr Training. Also add an entry to the PositiveSample.txt with the location of the item of interest. */ void saveFroHarrTraining(IplImage *src, int x, int y, int width, int height, int imageCount) { char f[255] ; sprintf(f,"%s\\%s\\harr_%s%d%d.jpg",strImageDir,strItemName,strItemName,imageCount/10, imageCount%10); cvNamedWindow("Harr", CV_WINDOW_AUTOSIZE); cvShowImage("Harr", src); cvSaveImage(f, src); printf("output%d%d \t ", imageCount/10, imageCount%10); printf("width %d \t", width); printf("height %d \t", height); printf("x1 %d \t", x); printf("y1 %d \t\n", y); char f1[255]; sprintf(f1,"%s\\PositiveSample.txt",strImageDir); FileDest = fopen(f1, "a"); fprintf(FileDest, "%s\\harr_%s%d.jpg 1 %d %d %d %d \n",strItemName,strItemName, imageCount, x, y, width, height); fclose(FileDest); } /* Create Sample Images for HMM recognition algorythm trai ning. */ void saveForHMMTraining(IplImage *src, CvRect roi,int imageCount) { char f[255] ; printf("x=%d, y=%d, w= %d, h= %d\n",roi.x,roi.y,roi.width,roi.height); //Create the file name sprintf(f,"%s\\%s\\hmm_%s%d.pgm",strImageDir,strItemName,strItemName, imageCount); //Create storage for grayscale image IplImage* gray = cvCreateImage(cvSize(roi.width,roi.height), 8, 1); //Create storage for croped reagon IplImage* regionFullImage = cvCreateImage(cvSize(roi.width,roi.height),8,3); //Croped marked region cvSetImageROI(src,roi); cvCopy(src,regionFullImage); cvResetImageROI(src); //Flip croped image - otherwise it will saved upside down cvConvertImage(regionFullImage, regionFullImage, CV_CVTIMG_FLIP); //Convert croped image to gray scale cvCvtColor(regionFullImage,gray, CV_BGR2GRAY); //Show final grayscale image cvNamedWindow("HMM", CV_WINDOW_AUTOSIZE); cvShowImage("HMM", gray); //Save final grayscale image cvSaveImage(f, gray); } int maina( int argc, char** argv ) { CvCapture* capture = 0; //if( argc == 1 || (argc == 2 && strlen(argv[1]) == 1 && isdigit(argv[1][0]))) // capture = cvCaptureFromCAM( argc == 2 ? argv[1][0] - '0' : 0 ); //else if( argc == 2 ) // capture = cvCaptureFromAVI( argv[1] ); char* video; if(argc ==7) { mode = atoi(argv[1]); strImageDir = argv[2]; strItemName = argv[3]; video = argv[4]; currentImageNo = atoi(argv[5]); int a = atoi(argv[6]); if(a==1) { isEqualRation = true; } else { isEqualRation = false; } } else { printf("\nUsage: TSCreator.exe <Mode> <Sample Image Save Path> <Sample Image Save Directory> <Video File Location> <Start Image No> <Is Equal Ratio>\n"); printf("Mode = 1 - Haar Traing Sample Creation. \nMode = 2 - HMM sample creation.\nMode = 3 - Both Harr and HMM\n"); printf("Is Equal Ratio = 0 or 1. 1 - Equal weidth and height, 0 - custom."); printf("Note: You have to create the image save directory in correct path first.\n"); printf("Eg: TSCreator.exe 1 E:\Projects\TSCreator\Images A 11.avi 1 1\n\n"); return 0; } capture = cvCaptureFromAVI(video); if( !capture ) { fprintf(stderr,"Could not initialize capturing...\n"); return -1; } cvNamedWindow("HMM-Harr Positive Image Creator", CV_WINDOW_AUTOSIZE); cvSetMouseCallback("HMM-Harr Positive Image Creator", on_mouse, 0); //cvShowImage("Test", image1); for(;;) { IplImage* frame = 0; int i, k, c; frame = cvQueryFrame( capture ); if( !frame ) break; if( !image ) { /* allocate all the buffers */ image = cvCreateImage( cvGetSize(frame), 8, 3 ); image->origin = frame->origin; //grey = cvCreateImage( cvGetSize(frame), 8, 1 ); //prev_grey = cvCreateImage( cvGetSize(frame), 8, 1 ); //pyramid = cvCreateImage( cvGetSize(frame), 8, 1 ); // prev_pyramid = cvCreateImage( cvGetSize(frame), 8, 1 ); points[0] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); points[1] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); status = (char*)cvAlloc(MAX_COUNT); flags = 0; } cvCopy( frame, image, 0 ); // cvCvtColor( image, grey, CV_BGR2GRAY ); cvShowImage("HMM-Harr Positive Image Creator", image); cvSetMouseCallback("HMM-Harr Positive Image Creator", on_mouse, 0); c = cvWaitKey(0); if((char)c == 's') { //Save selected reagion as training data if(selectedImage) { printf("Selected Reagion Saved\n"); if(mode == 1) { saveFroHarrTraining(selectedImage,selectedX,selectedY,selectedWidth,selectedHeight,currentImageNo); } else if(mode == 2) { saveForHMMTraining(selectedImage,selectedROI,currentImageNo); } else if(mode ==3) { saveFroHarrTraining(selectedImage,selectedX,selectedY,selectedWidth,selectedHeight,currentImageNo); saveForHMMTraining(selectedImage,selectedROI,currentImageNo); } else { printf("Invalid mode."); } currentImageNo++; } } } cvReleaseCapture( &capture ); //cvDestroyWindow("HMM-Harr Positive Image Creator"); cvDestroyAllWindows(); return 0; } #ifdef _EiC main(1,"lkdemo.c"); #endif If I put... #include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { return 0; } ... before the previous code (and link it to the correct OpenCV .lib files) it compiles without errors, but does nothing at the command line. How do I make it work?

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  • Streamed mp3 only plays for 1 second

    - by angel6
    Hi, I'm using the plaympeg.c (modified) code of smpeg as a media player. I've got ffserver running as a streaming server. I'm a streaming an mp3 file over http. But when I run plaympeg.c, it plays the streamed file only for a second. When I run plaympeg again, it starts off from where it left and plays for 1 second. Does anyone know why this happens an how to fix it? I've tested it out on WMP and it plays the entire file in one go. So, i guess it's not a problem with the streaming or ffserver.conf include include include include /* #ifdef unix */ include include include include include include include define NET_SUPPORT /* General network support */ define HTTP_SUPPORT /* HTTP support */ ifdef NET_SUPPORT include include include include endif include "smpeg.h" ifdef NET_SUPPORT int tcp_open(char * address, int port) { struct sockaddr_in stAddr; struct hostent * host; int sock; struct linger l; memset(&stAddr,0,sizeof(stAddr)); stAddr.sin_family = AF_INET ; stAddr.sin_port = htons(port); if((host = gethostbyname(address)) == NULL) return(0); stAddr.sin_addr = *((struct in_addr *) host-h_addr_list[0]) ; if((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) return(0); l.l_onoff = 1; l.l_linger = 5; if(setsockopt(sock, SOL_SOCKET, SO_LINGER, (char*) &l, sizeof(l)) < 0) return(0); if(connect(sock, (struct sockaddr *) &stAddr, sizeof(stAddr)) < 0) return(0); return(sock); } ifdef HTTP_SUPPORT int http_open(char * arg) { char * host; int port; char * request; int tcp_sock; char http_request[1024]; char c; printf("\nin http_open passed parameter = %s\n",arg); /* Check for URL syntax */ if(strncmp(arg, "http://", strlen("http://"))) return(0); /* Parse URL */ port = 80; host = arg + strlen("http://"); if((request = strchr(host, '/')) == NULL) return(0); request++ = 0; if(strchr(host, ':') != NULL) / port is specified */ { port = atoi(strchr(host, ':') + 1); *strchr(host, ':') = 0; } /* Open a TCP socket */ if(!(tcp_sock = tcp_open(host, port))) { perror("http_open"); return(0); } /* Send HTTP GET request */ sprintf(http_request, "GET /%s HTTP/1.0\r\n" "User-Agent: Mozilla/2.0 (Win95; I)\r\n" "Pragma: no-cache\r\n" "Host: %s\r\n" "Accept: /\r\n" "\r\n", request, host); send(tcp_sock, http_request, strlen(http_request), 0); /* Parse server reply */ do read(tcp_sock, &c, sizeof(char)); while(c != ' '); read(tcp_sock, http_request, 4*sizeof(char)); http_request[4] = 0; if(strcmp(http_request, "200 ")) { fprintf(stderr, "http_open: "); do { read(tcp_sock, &c, sizeof(char)); fprintf(stderr, "%c", c); } while(c != '\r'); fprintf(stderr, "\n"); return(0); } return(tcp_sock); } endif endif void update(SDL_Surface *screen, Sint32 x, Sint32 y, Uint32 w, Uint32 h) { if ( screen-flags & SDL_DOUBLEBUF ) { SDL_Flip(screen); } } /* Flag telling the UI that the movie or song should be skipped */ int done; void next_movie(int sig) { done = 1; } int main(int argc, char *argv[]) { int use_audio, use_video; int fullscreen; int scalesize; int scale_width, scale_height; int loop_play; int i, pause; int volume; Uint32 seek; float skip; int bilinear_filtering; SDL_Surface *screen; SMPEG *mpeg; SMPEG_Info info; char *basefile; SDL_version sdlver; SMPEG_version smpegver; int fd; char buf[32]; int status; printf("\nchecking command line options "); /* Get the command line options */ use_audio = 1; use_video = 1; fullscreen = 0; scalesize = 1; scale_width = 0; scale_height = 0; loop_play = 0; volume = 100; seek = 0; skip = 0; bilinear_filtering = 0; fd = 0; for ( i=1; argv[i] && (argv[i][0] == '-') && (argv[i][1] != 0); ++i ) { if ( strcmp(argv[i], "--fullscreen") == 0 ) { fullscreen = 1; } else if ((strcmp(argv[i], "--seek") == 0)||(strcmp(argv[i], "-S") == 0)) { ++i; if ( argv[i] ) { seek = atol(argv[i]); } } else if ((strcmp(argv[i], "--volume") == 0)||(strcmp(argv[i], "-v") == 0)) { ++i; if (i >= argc) { fprintf(stderr, "Please specify volume when using --volume or -v\n"); return(1); } if ( argv[i] ) { volume = atoi(argv[i]); } if ( ( volume < 0 ) || ( volume 100 ) ) { fprintf(stderr, "Volume must be between 0 and 100\n"); volume = 100; } } else { fprintf(stderr, "Warning: Unknown option: %s\n", argv[i]); } } printf("\nuse video = %d, use audio = %d\n",use_video, use_audio); printf("\ngoing to check input parameters\n"); if defined(linux) || defined(FreeBSD) /* Plaympeg doesn't need a mouse */ putenv("SDL_NOMOUSE=1"); endif /* Play the mpeg files! */ status = 0; for ( ; argv[i]; ++i ) { /* Initialize SDL */ if ( use_video ) { if ((SDL_Init(SDL_INIT_VIDEO) < 0) || !SDL_VideoDriverName(buf, 1)) { fprintf(stderr, "Warning: Couldn't init SDL video: %s\n", SDL_GetError()); fprintf(stderr, "Will ignore video stream\n"); use_video = 0; } printf("\ninitialised video\n"); } if ( use_audio ) { if ((SDL_Init(SDL_INIT_AUDIO) < 0) || !SDL_AudioDriverName(buf, 1)) { fprintf(stderr, "Warning: Couldn't init SDL audio: %s\n", SDL_GetError()); fprintf(stderr, "Will ignore audio stream\n"); use_audio = 0; } } /* Allow Ctrl-C when there's no video output */ signal(SIGINT, next_movie); printf("\nchecking defined supports\n"); /* Create the MPEG stream */ ifdef NET_SUPPORT printf("\ndefined NET_SUPPORT\n"); ifdef HTTP_SUPPORT printf("\ndefined HTTP_SUPPORT\n"); /* Check if source is an http URL */ printf("\nabout to call http_open\n"); printf("\nhere we go\n"); if((fd = http_open(argv[i])) != 0) mpeg = SMPEG_new_descr(fd, &info, use_audio); else endif endif { if(strcmp(argv[i], "-") == 0) /* Use stdin for input */ mpeg = SMPEG_new_descr(0, &info, use_audio); else mpeg = SMPEG_new(argv[i], &info, use_audio); } if ( SMPEG_error(mpeg) ) { fprintf(stderr, "%s: %s\n", argv[i], SMPEG_error(mpeg)); SMPEG_delete(mpeg); status = -1; continue; } SMPEG_enableaudio(mpeg, use_audio); SMPEG_enablevideo(mpeg, use_video); SMPEG_setvolume(mpeg, volume); /* Print information about the video */ basefile = strrchr(argv[i], '/'); if ( basefile ) { ++basefile; } else { basefile = argv[i]; } if ( info.has_audio && info.has_video ) { printf("%s: MPEG system stream (audio/video)\n", basefile); } else if ( info.has_audio ) { printf("%s: MPEG audio stream\n", basefile); } else if ( info.has_video ) { printf("%s: MPEG video stream\n", basefile); } if ( info.has_video ) { printf("\tVideo %dx%d resolution\n", info.width, info.height); } if ( info.has_audio ) { printf("\tAudio %s\n", info.audio_string); } if ( info.total_size ) { printf("\tSize: %d\n", info.total_size); } if ( info.total_time ) { printf("\tTotal time: %f\n", info.total_time); } /* Set up video display if needed */ if ( info.has_video && use_video ) { const SDL_VideoInfo *video_info; Uint32 video_flags; int video_bpp; int width, height; /* Get the "native" video mode */ video_info = SDL_GetVideoInfo(); switch (video_info->vfmt->BitsPerPixel) { case 16: case 24: case 32: video_bpp = video_info->vfmt->BitsPerPixel; break; default: video_bpp = 16; break; } if ( scale_width ) { width = scale_width; } else { width = info.width; } width *= scalesize; if ( scale_height ) { height = scale_height; } else { height = info.height; } height *= scalesize; video_flags = SDL_SWSURFACE; if ( fullscreen ) { video_flags = SDL_FULLSCREEN|SDL_DOUBLEBUF|SDL_HWSURFACE; } video_flags |= SDL_ASYNCBLIT; video_flags |= SDL_RESIZABLE; screen = SDL_SetVideoMode(width, height, video_bpp, video_flags); if ( screen == NULL ) { fprintf(stderr, "Unable to set %dx%d video mode: %s\n", width, height, SDL_GetError()); continue; } SDL_WM_SetCaption(argv[i], "plaympeg"); if ( screen->flags & SDL_FULLSCREEN ) { SDL_ShowCursor(0); } SMPEG_setdisplay(mpeg, screen, NULL, update); SMPEG_scaleXY(mpeg, screen->w, screen->h); } else { SDL_QuitSubSystem(SDL_INIT_VIDEO); } /* Set any special playback parameters */ if ( loop_play ) { SMPEG_loop(mpeg, 1); } /* Seek starting position */ if(seek) SMPEG_seek(mpeg, seek); /* Skip seconds to starting position */ if(skip) SMPEG_skip(mpeg, skip); /* Play it, and wait for playback to complete */ SMPEG_play(mpeg); done = 0; pause = 0; while ( ! done && ( pause || (SMPEG_status(mpeg) == SMPEG_PLAYING) ) ) { SDL_Event event; while ( use_video && SDL_PollEvent(&event) ) { switch (event.type) { case SDL_VIDEORESIZE: { SDL_Surface *old_screen = screen; SMPEG_pause(mpeg); screen = SDL_SetVideoMode(event.resize.w, event.resize.h, screen->format->BitsPerPixel, screen->flags); if ( old_screen != screen ) { SMPEG_setdisplay(mpeg, screen, NULL, update); } SMPEG_scaleXY(mpeg, screen-w, screen-h); SMPEG_pause(mpeg); } break; case SDL_KEYDOWN: if ( (event.key.keysym.sym == SDLK_ESCAPE) || (event.key.keysym.sym == SDLK_q) ) { // Quit done = 1; } else if ( event.key.keysym.sym == SDLK_RETURN ) { // toggle fullscreen if ( event.key.keysym.mod & KMOD_ALT ) { SDL_WM_ToggleFullScreen(screen); fullscreen = (screen-flags & SDL_FULLSCREEN); SDL_ShowCursor(!fullscreen); } } else if ( event.key.keysym.sym == SDLK_UP ) { // Volume up if ( volume < 100 ) { if ( event.key.keysym.mod & KMOD_SHIFT ) { // 10+ volume += 10; } else if ( event.key.keysym.mod & KMOD_CTRL ) { // 100+ volume = 100; } else { // 1+ volume++; } if ( volume 100 ) volume = 100; SMPEG_setvolume(mpeg, volume); } } else if ( event.key.keysym.sym == SDLK_DOWN ) { // Volume down if ( volume 0 ) { if ( event.key.keysym.mod & KMOD_SHIFT ) { volume -= 10; } else if ( event.key.keysym.mod & KMOD_CTRL ) { volume = 0; } else { volume--; } if ( volume < 0 ) volume = 0; SMPEG_setvolume(mpeg, volume); } } else if ( event.key.keysym.sym == SDLK_PAGEUP ) { // Full volume volume = 100; SMPEG_setvolume(mpeg, volume); } else if ( event.key.keysym.sym == SDLK_PAGEDOWN ) { // Volume off volume = 0; SMPEG_setvolume(mpeg, volume); } else if ( event.key.keysym.sym == SDLK_SPACE ) { // Toggle play / pause if ( SMPEG_status(mpeg) == SMPEG_PLAYING ) { SMPEG_pause(mpeg); pause = 1; } else { SMPEG_play(mpeg); pause = 0; } } else if ( event.key.keysym.sym == SDLK_RIGHT ) { // Forward if ( event.key.keysym.mod & KMOD_SHIFT ) { SMPEG_skip(mpeg, 100); } else if ( event.key.keysym.mod & KMOD_CTRL ) { SMPEG_skip(mpeg, 50); } else { SMPEG_skip(mpeg, 5); } } else if ( event.key.keysym.sym == SDLK_LEFT ) { // Reverse if ( event.key.keysym.mod & KMOD_SHIFT ) { } else if ( event.key.keysym.mod & KMOD_CTRL ) { } else { } } else if ( event.key.keysym.sym == SDLK_KP_MINUS ) { // Scale minus if ( scalesize > 1 ) { scalesize--; } } else if ( event.key.keysym.sym == SDLK_KP_PLUS ) { // Scale plus scalesize++; } else if ( event.key.keysym.sym == SDLK_f ) { // Toggle filtering on/off if ( bilinear_filtering ) { SMPEG_Filter *filter = SMPEGfilter_null(); filter = SMPEG_filter( mpeg, filter ); filter-destroy(filter); bilinear_filtering = 0; } else { SMPEG_Filter *filter = SMPEGfilter_bilinear(); filter = SMPEG_filter( mpeg, filter ); filter-destroy(filter); bilinear_filtering = 1; } } break; case SDL_QUIT: done = 1; break; default: break; } } SDL_Delay(1000/2); } SMPEG_delete(mpeg); } SDL_Quit(); if defined(HTTP_SUPPORT) if(fd) close(fd); endif return(status); }

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  • Fread binary file dynamic size string [C]

    - by Blackbinary
    I've been working on this assignment, where I need to read in "records" and write them to a file, and then have the ability to read/find them later. On each run of the program, the user can decide to write a new record, or read an old record (either by Name or #) The file is binary, here is its definition: typedef struct{ char * name; char * address; short addressLength, nameLength; int phoneNumber; }employeeRecord; employeeRecord record; The way the program works, it will store the structure, then the name, then the address. Name and address are dynamically allocated, which is why it is necessary to read the structure first to find the size of the name and address, allocate memory for them, then read them into that memory. For debugging purposes I have two programs at the moment. I have my file writing program, and file reading. My actual problem is this, when I read a file I have written, i read in the structure, print out the phone # to make sure it works (which works fine), and then fread the name (now being able to use record.nameLength which reports the proper value too). Fread however, does not return a usable name, it returns blank. I see two problems, either I haven't written the name to the file correctly, or I haven't read it in correctly. Here is how i write to the file: where fp is the file pointer. record.name is a proper value, so is record.nameLength. Also i am writing the name including the null terminator. (e.g. 'Jack\0') fwrite(&record,sizeof record,1,fp); fwrite(record.name,sizeof(char),record.nameLength,fp); fwrite(record.address,sizeof(char),record.addressLength,fp); And i then close the file. here is how i read the file: fp = fopen("employeeRecord","r"); fread(&record,sizeof record,1,fp); printf("Number: %d\n",record.phoneNumber); char *nameString = malloc(sizeof(char)*record.nameLength); printf("\nName Length: %d",record.nameLength); fread(nameString,sizeof(char),record.nameLength,fp); printf("\nName: %s",nameString); Notice there is some debug stuff in there (name length and number, both of which are correct). So i know the file opened properly, and I can use the name length fine. Why then is my output blank, or a newline, or something like that? (The output is just Name: with nothing after it, and program finishes just fine) Thanks for the help.

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  • function parameter used to store value

    - by user248247
    Hi, I have to define an interface. The API in my homework is stated below: int generate_codes(char * ssn, char * student_id); int denotes 0 or 1 for pass or fail. studentid is an output param should return a 6 digit id. ssn is a 9 digit input param they school program will take ssn's and use my code to generate the student id. now from an API perspective should I not be using const char * for both parameters. should the studentid not be passed in by reference? rather than by pointer? can someone tell me how i can easily use the pointer in my test app which uses my api to get the pointer such that it prints a std::string from a char *? my app code looks something like const char * ssn = "987098765" const char * studnt_id = new char [7]; int value = -1; value = generate_codes(ssn,studnt_id); std::string test(studnt_id); std::cout<<"student id= "<<test<<" Pass/fail= "<<value<<std::endl; delete [] studnt_id; return 0; I basically got an error about << not being compatible with the right hand side of the operand. When i changed the code to std::cout<<"student id= "<<test.c_str()<<" Pass/fail= "<<value<<std::endl; then it worked but i get garbage for the value. not sure how to do get the value form the pointer. THe value inside the function prints just fine. but when i try to print it outside of the function it prints garbage. Inside the above function I do set the studndt_id like so std::string str_studnt_id = studnt_id; should that make the address of the str_studnt point to the address of studnt_id and thus any changes I make to the value that its pointing to it should reflect outside the function?

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  • OpenGL Shader Compile Error

    - by Tomas Cokis
    I'm having a bit of a problem with my code for compiling shaders, namely they both register as failed compiles and no log is received. This is the shader compiling code: /* Make the shader */ Uint size; GLchar* file; loadFileRaw(filePath, file, &size); const char * pFile = file; const GLint pSize = size; newCashe.shader = glCreateShader(shaderType); glShaderSource(newCashe.shader, 1, &pFile, &pSize); glCompileShader(newCashe.shader); GLint shaderCompiled; glGetShaderiv(newCashe.shader, GL_COMPILE_STATUS, &shaderCompiled); if(shaderCompiled == GL_FALSE) { ReportFiler->makeReport("ShaderCasher.cpp", "loadShader()", "Shader did not compile", "The shader " + filePath + " failed to compile, reporting the error - " + OpenGLServices::getShaderLog(newCashe.shader)); } And these are the support functions: bool loadFileRaw(string fileName, char* data, Uint* size) { if (fileName != "") { FILE *file = fopen(fileName.c_str(), "rt"); if (file != NULL) { fseek(file, 0, SEEK_END); *size = ftell(file); rewind(file); if (*size > 0) { data = (char*)malloc(sizeof(char) * (*size + 1)); *size = fread(data, sizeof(char), *size, file); data[*size] = '\0'; } fclose(file); } } return data; } string OpenGLServices::getShaderLog(GLuint obj) { int infologLength = 0; int charsWritten = 0; char *infoLog; glGetShaderiv(obj, GL_INFO_LOG_LENGTH,&infologLength); if (infologLength > 0) { infoLog = (char *)malloc(infologLength); glGetShaderInfoLog(obj, infologLength, &charsWritten, infoLog); string log = infoLog; free(infoLog); return log; } return "<Blank Log>"; } and the shaders I'm loading: void main(void) { gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); } void main(void) { gl_Position = ftransform(); } In short I get From: ShaderCasher.cpp, In: loadShader(), Subject: Shader did not compile Message: The shader Data/Shaders/Standard/standard.vs failed to compile, reporting the error - <Blank Log> for every shader I compile I've tried replacing the file reading with just a hard coded string but I get the same error so there must be something wrong with how I'm compiling them. I have run and compiled example programs with shaders, so I doubt my drivers are the issue, but in any case I'm on a Nvidia 8600m GT. Can anyone help?

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  • C++ beginner question regarding chars

    - by Samwhoo
    I'm just messing around with some C++ at the moment trying to make a simple tic-tac-toe game and I'm running into a bit of a problem. This is my code: #include <iostream> using namespace std; class Square { public: char getState() const; void setState(char); Square(); ~Square(); private: char * pState; }; class Board { public: Board(); ~Board(); void printBoard() const; Square getSquare(short x, short y) const; private: Square board[3][3]; }; int main() { Board board; board.getSquare(1,2).setState('1'); board.printBoard(); return 0; } Square::Square() { pState = new char; *pState = ' '; } Square::~Square() { delete pState; } char Square::getState() const { return *pState; } void Square::setState(char set) { *pState = set; } Board::~Board() { } Board::Board() { } void Board::printBoard() const { for (int x = 0; x < 3; x++) { cout << "|"; for (int y = 0; y < 3; y++) { cout << board[x][y].getState(); } cout << "|" << endl; } } Square Board::getSquare(short x, short y) const { return board[x][y]; } Forgive me if there are blatantly obvious problems with it or it's stupidly written, this is my first program in C++ :p However, the problem is that when I try and set the square 1,2 to the char '1', it doesn't print out as a 1, it prints out as some strange character I didn't recognise. Can anyone tell me why? :) Thanks in advance.

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  • best alternative to in-definition initialization of static class members? (for SVN keywords)

    - by Jeff
    I'm storing expanded SVN keyword literals for .cpp files in 'static char const *const' class members and want to store the .h descriptions as similarly as possible. In short, I need to guarantee single instantiation of a static member (presumably in a .cpp file) to an auto-generated non-integer literal living in a potentially shared .h file. Unfortunately the language makes no attempt to resolve multiple instantiations resulting from assignments made outside class definitions and explicitly forbids non-integer inits inside class definitions. My best attempt (using static-wrapping internal classes) is not too dirty, but I'd really like to do better. Does anyone have a way to template the wrapper below or have an altogether superior approach? // Foo.h: class with .h/.cpp SVN info stored and logged statically class Foo { static Logger const verLog; struct hInfoWrap; public: static hInfoWrap const hInfo; static char const *const cInfo; }; // Would like to eliminate this per-class boilerplate. struct Foo::hInfoWrap { hInfoWrapper() : text("$Id$") { } char const *const text; }; ... // Foo.cpp: static inits called here Foo::hInfoWrap const Foo::hInfo; char const *const Foo::cInfo = "$Id$"; Logger const Foo::verLog(Foo::cInfo, Foo::hInfo.text); ... // Helper.h: output on construction, with no subsequent activity or stored fields class Logger { Logger(char const *info1, char const *info2) { cout << info0 << endl << info1 << endl; } }; Is there a way to get around the static linkage address issue for templating the hInfoWrap class on string literals? Extern char pointers assigned outside class definitions are linguistically valid but fail in essentially the same manner as direct member initializations. I get why the language shirks the whole resolution issue, but it'd be very convenient if an inverted extern member qualifier were provided, where the definition code was visible in class definitions to any caller but only actually invoked at the point of a single special declaration elsewhere. Anyway, I digress. What's the best solution for the language we've got, template or otherwise? Thanks!

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  • processing an audio wav file with C

    - by sa125
    Hi - I'm working on processing the amplitude of a wav file and scaling it by some decimal factor. I'm trying to wrap my head around how to read and re-write the file in a memory-efficient way while also trying to tackle the nuances of the language (I'm new to C). The file can be in either an 8- or 16-bit format. The way I thought of doing this is by first reading the header data into some pre-defined struct, and then processing the actual data in a loop where I'll read a chunk of data into a buffer, do whatever is needed to it, and then write it to the output. #include <stdio.h> #include <stdlib.h> typedef struct header { char chunk_id[4]; int chunk_size; char format[4]; char subchunk1_id[4]; int subchunk1_size; short int audio_format; short int num_channels; int sample_rate; int byte_rate; short int block_align; short int bits_per_sample; short int extra_param_size; char subchunk2_id[4]; int subchunk2_size; } header; typedef struct header* header_p; void scale_wav_file(char * input, float factor, int is_8bit) { FILE * infile = fopen(input, "rb"); FILE * outfile = fopen("outfile.wav", "wb"); int BUFSIZE = 4000, i, MAX_8BIT_AMP = 255, MAX_16BIT_AMP = 32678; // used for processing 8-bit file unsigned char inbuff8[BUFSIZE], outbuff8[BUFSIZE]; // used for processing 16-bit file short int inbuff16[BUFSIZE], outbuff16[BUFSIZE]; // header_p points to a header struct that contains the file's metadata fields header_p meta = (header_p)malloc(sizeof(header)); if (infile) { // read and write header data fread(meta, 1, sizeof(header), infile); fwrite(meta, 1, sizeof(meta), outfile); while (!feof(infile)) { if (is_8bit) { fread(inbuff8, 1, BUFSIZE, infile); } else { fread(inbuff16, 1, BUFSIZE, infile); } // scale amplitude for 8/16 bits for (i=0; i < BUFSIZE; ++i) { if (is_8bit) { outbuff8[i] = factor * inbuff8[i]; if ((int)outbuff8[i] > MAX_8BIT_AMP) { outbuff8[i] = MAX_8BIT_AMP; } } else { outbuff16[i] = factor * inbuff16[i]; if ((int)outbuff16[i] > MAX_16BIT_AMP) { outbuff16[i] = MAX_16BIT_AMP; } else if ((int)outbuff16[i] < -MAX_16BIT_AMP) { outbuff16[i] = -MAX_16BIT_AMP; } } } // write to output file for 8/16 bit if (is_8bit) { fwrite(outbuff8, 1, BUFSIZE, outfile); } else { fwrite(outbuff16, 1, BUFSIZE, outfile); } } } // cleanup if (infile) { fclose(infile); } if (outfile) { fclose(outfile); } if (meta) { free(meta); } } int main (int argc, char const *argv[]) { char infile[] = "file.wav"; float factor = 0.5; scale_wav_file(infile, factor, 0); return 0; } I'm getting differing file sizes at the end (by 1k or so, for a 40Mb file), and I suspect this is due to the fact that I'm writing an entire buffer to the output, even though the file may have terminated before filling the entire buffer size. Also, the output file is messed up - won't play or open - so I'm probably doing the whole thing wrong. Any tips on where I'm messing up will be great. Thanks!

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  • STL operator= behavior change with Visual Studio 2010?

    - by augnob
    Hi, I am attempting to compile QtScriptGenerator (gitorious) with Visual Studio 2010 (C++) and have run into a compile error. In searching for a solution, I have seen occasional references to compile breakages introduced since VS2008 due to changes in VS2010's implementation of STL and/or c++0x conformance changes. Any ideas what is happening below, or how I could go about fixing it? If the offending code appeared to be QtScriptGenerator's, I think I would have an easier time fixing it.. but it appears to me that the offending code may be in VS2010's STL implementation and I may be required to create a workaround? PS. I am pretty unfamiliar with templates and STL. I have a background in embedded and console projects where such things have until recently often been avoided to reduce memory consumption and cross-compiler risks. C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xutility(275) : error C2679: binary '=' : no operator found which takes a right-hand operand of type 'rpp::pp_output_iterator<_Container>' (or there is no acceptable conversion) with [ _Container=std::string ] c:\qt\qtscriptgenerator\generator\parser\rpp\pp-iterator.h(75): could be 'rpp::pp_output_iterator<_Container> &rpp::pp_output_iterator<_Container>::operator =(const char &)' with [ _Container=std::string ] while trying to match the argument list '(rpp::pp_output_iterator<_Container>, rpp::pp_output_iterator<_Container>)' with [ _Container=std::string ] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xutility(2176) : see reference to function template instantiation '_Iter &std::_Rechecked<_OutIt,_OutIt>(_Iter &,_UIter)' being compiled with [ _Iter=rpp::pp_output_iterator<std::string>, _OutIt=rpp::pp_output_iterator<std::string>, _UIter=rpp::pp_output_iterator<std::string> ] c:\qt\qtscriptgenerator\generator\parser\rpp\pp-internal.h(83) : see reference to function template instantiation '_OutIt std::copy<std::_String_iterator<_Elem,_Traits,_Alloc>,_OutputIterator>(_InIt,_InIt,_OutIt)' being compiled with [ _OutIt=rpp::pp_output_iterator<std::string>, _Elem=char, _Traits=std::char_traits<char>, _Alloc=std::allocator<char>, _OutputIterator=rpp::pp_output_iterator<std::string>, _InIt=std::_String_iterator<char,std::char_traits<char>,std::allocator<char>> ] c:\qt\qtscriptgenerator\generator\parser\rpp\pp-engine-bits.h(500) : see reference to function template instantiation 'void rpp::_PP_internal::output_line<_OutputIterator>(const std::string &,int,_OutputIterator)' being compiled with [ _OutputIterator=rpp::pp_output_iterator<std::string> ] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xutility(275) : error C2582: 'operator =' function is unavailable in 'rpp::pp_output_iterator<_Container>' with [ _Container=std::string ] Here's some context.. pp-internal.h-- #ifndef PP_INTERNAL_H #define PP_INTERNAL_H #include <algorithm> #include <stdio.h> namespace rpp { namespace _PP_internal { .. 68 template <typename _OutputIterator> 69 void output_line(const std::string &__filename, int __line, _OutputIterator __result) 70 { 71 std::string __msg; 72 73 __msg += "# "; 74 75 char __line_descr[16]; 76 pp_snprintf (__line_descr, 16, "%d", __line); 77 __msg += __line_descr; 78 79 __msg += " \""; 80 81 if (__filename.empty ()) 82 __msg += "<internal>"; 83 else 84 __msg += __filename; 85 86 __msg += "\"\n"; 87 std::copy (__msg.begin (), __msg.end (), __result); 88 }

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  • Can printf change its parameters??

    - by martani_net
    EDIT: complete code with main is here http://codepad.org/79aLzj2H and once again this is were the weird behavious is happening for (i = 0; i<tab_size; i++) { //CORRECT OUTPUT printf("%s\n", tableau[i].capitale); printf("%s", tableau[i].pays); printf("%s\n", tableau[i].commentaire); //WRONG OUTPUT //printf("%s --- %s --- %s |\n", tableau[i].capitale, tableau[i].pays, tableau[i].commentaire); } I have an array of the following strcuture struct T_info { char capitale[255]; char pays[255]; char commentaire[255]; }; struct T_info *tableau; This is how the array is populated int advance(FILE *f) { char c; c = getc(f); if(c == '\n') return 0; while(c != EOF && (c == ' ' || c == '\t')) { c = getc(f); } return fseek(f, -1, SEEK_CUR); } int get_word(FILE *f, char * buffer) { char c; int count = 0; int space = 0; while((c = getc(f)) != EOF) { if (c == '\n') { buffer[count] = '\0'; return -2; } if ((c == ' ' || c == '\t') && space < 1) { buffer[count] = c; count ++; space++; } else { if (c != ' ' && c != '\t') { buffer[count] = c; count ++; space = 0; } else /* more than one space*/ { advance(f); break; } } } buffer[count] = '\0'; if(c == EOF) return -1; return count; } void fill_table(FILE *f,struct T_info *tab) { int line = 0, column = 0; fseek(f, 0, SEEK_SET); char buffer[MAX_LINE]; char c; int res; int i = 0; while((res = get_word(f, buffer)) != -999) { switch(column) { case 0: strcpy(tab[line].capitale, buffer); column++; break; case 1: strcpy(tab[line].pays, buffer); column++; break; default: strcpy(tab[line].commentaire, buffer); column++; break; } /*if I printf each one alone here, everything works ok*/ //last word in line if (res == -2) { if (column == 2) { strcpy(tab[line].commentaire, " "); } //wrong output here printf("%s -- %s -- %s\n", tab[line].capitale, tab[line].pays, tab[line].commentaire); column = 0; line++; continue; } column = column % 3; if (column == 0) { line++; } /*EOF reached*/ if(res == -1) return; } return ; } Edit : trying this printf("%s -- ", tab[line].capitale); printf("%s --", tab[line].pays); printf("%s --\n", tab[line].commentaire); gives me as result -- --abi -- Emirats arabes unis I expect to get Abu Dhabi -- Emirats arabes unis -- Am I missing something?

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  • Segmentation. strcmp [C]

    - by FILIaS
    Hello, I have a file with format: [name][number][amount] number is taken as a string. and im using it in a strcmp. Problem is that i get a segmentation fault. I know that on most cases when strcmp signs segmentation fault it means that one of the parameters is null or cant find its "end" ('\0'). I checked with gdb and i cant say if this is the problem.Take a look: > (gdb) bt full > #0 0x08048729 in lookup (hashtable=0x804b008, hashval=27, > number=0x804b740 "6900101001") > list = 0xffffffff > #1 0x080487ac in add (hashtable=0x804b008, > number=0x804b740 "9900101001", name=0x804b730 "Smithpolow", > time=6943) > new_elem = 0xffffffff > hashval = 27 > #2 0x08048b25 in main (argc=1, argv=0xbffff4b4) > number = 0x804b740 "9900101001" > name = 0x804b730 "Smithpolow" > time = 6943 > i = 2 Code: clientsList *lookup_on_Clients(clientsHashTable *hashtable,int hashval,char number[10]) { printf("NUMBER:%s\n",number); clientsList *list=hashtable[hashval].head; for(list; list!=NULL; list=list->next){ if (strcmp(number,list->number)==0) //SEGMENTATION! return list; } return NULL; } int add ( HashTable* hashtable,char number[10],char* name,int time) { List *new_elem; int hashval=hash (hashtable,number); new_elem=hashtable[hashval].head; if(hashtable[hashval].length>0) { if ((lookup (hashtable,hashval,number))!=NULL) {return 0;} } //an den uparxei stoixeio sth lista if (!(new_elem=malloc(sizeof(struct clientsList)))){ return -1;} //insert values for the new elem new_elem->number=strdup(number); new_elem->name=strdup(name); new_elem->time=time; hashtable[hashval].head=new_elem; new_elem->next=NULL; hashtable[hashval].length++; /* rehash existing entries if necessary */ if(hashTableSize(hashtable)>= 2*primes[PrimesIndex]) { hashtable = expand(hashtable); if (hashtable ==NULL){ return 0; } PrimesIndex++; } return 1; } and the main: FILE * File2; if ( ( File2=fopen(" File.txt","r")) !=NULL ) { // File.txt format: [name number time] e.g lountemis 6900254565 700651 int li = 0; char *lin = (char *) malloc(MAX_LINE * sizeof(char)); while(fgets(lin, MAX_LINE, clientFile2) != NULL) { token = my_linetok(lin, " "); if(token != NULL) { char* number ; char* name; int time; int i; for(i = 0; token[i] != NULL; i++) { name=strdup(token[0]); number=strdup(token[1]); time=atoi(token[2]); if (i==2) { int insertDone=0; insertDone =add(my_hash_table,number,name,time); } } free(name); free(number); free(token); } else { printf("Error reading line %s\n", lin); exit(1); } } } else { printf("Error opening file \nEXIT!"); exit(0); }

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  • How do you read from a file into an array of struct?

    - by Thomas.Winsnes
    I'm currently working on an assignment and this have had me stuck for hours. Can someone please help me point out why this isn't working for me? struct book { char title[25]; char author[50]; char subject[20]; int callNumber; char publisher[250]; char publishDate[11]; char location[20]; char status[11]; char type[12]; int circulationPeriod; int costOfBook; }; void PrintBookList(struct book **bookList) { int i; for(i = 0; i < sizeof(bookList); i++) { struct book newBook = *bookList[i]; printf("%s;%s;%s;%d;%s;%s;%s;%s;%s;%d;%d\n",newBook.title, newBook.author, newBook.subject, newBook.callNumber,newBook.publisher, newBook.publishDate, newBook.location, newBook.status, newBook.type,newBook.circulationPeriod, newBook.costOfBook); } } void GetBookList(struct book** bookList) { FILE* file = fopen("book.txt", "r"); struct book newBook[1024]; int i = 0; while(fscanf(file, "%s;%s;%s;%d;%s;%s;%s;%s;%s;%d;%d", &newBook[i].title, &newBook[i].author, &newBook[i].subject, &newBook[i].callNumber,&newBook[i].publisher, &newBook[i].publishDate, &newBook[i].location, &newBook[i].status, &newBook[i].type,&newBook[i].circulationPeriod, &newBook[i].costOfBook) != EOF) { bookList[i] = &newBook[i]; i++; } /*while(fscanf(file, "%s;%s;%s;%d;%s;%s;%s;%s;%s;%d;%d", &bookList[i].title, &bookList[i].author, &bookList[i].subject, &bookList[i].callNumber, &bookList[i].publisher, &bookList[i].publishDate, &bookList[i].location, &bookList[i].status, &bookList[i].type, &bookList[i].circulationPeriod, &bookList[i].costOfBook) != EOF) { i++; }*/ PrintBookList(bookList); fclose(file); } int main() { struct book *bookList[1024]; GetBookList(bookList); } I get no errors or warnings on compile it should print the content of the file, just like it is in the file. Like this: OperatingSystems Internals and Design principles;William.S;IT;741012759;Upper Saddle River;2009;QA7676063;Available;circulation;3;11200 Communication skills handbook;Summers.J;Accounting;771239216;Milton;2010;BF637C451;Available;circulation;3;7900 Business marketing management:B2B;Hutt.D;Management;741912319;Mason;2010;HF5415131;Available;circulation;3;1053 Patient education rehabilitation;Dreeben.O;Education;745121511;Sudbury;2010;CF5671A98;Available;reference;0;6895 Tomorrow's technology and you;Beekman.G;Science;764102174;Upper Saddle River;2009;QA76B41;Out;reserved;1;7825 Property & security: selected essay;Cathy.S;Law;750131231;Rozelle;2010;D4A3C56;Available;reference;0;20075 Introducing communication theory;Richard.W;IT;714789013;McGraw-Hill;2010;Q360W47;Available;circulation;3;12150 Maths for computing and information technology;Giannasi.F;Mathematics;729890537;Longman;Scientific;1995;QA769M35G;Available;reference;0;13500 Labor economics;George.J;Economics;715784761;McGraw-Hill;2010;HD4901B67;Available;circulation;3;7585 Human physiology:from cells to systems;Sherwood.L;Physiology;707558936;Cengage Learning;2010;QP345S32;Out;circulation;3;11135 bobs;thomas;IT;701000000;UC;1006;QA7548;Available;Circulation;7;5050 but when I run it, it outputs this: OperatingSystems;;;0;;;;;;0;0 Internals;;;0;;;;;;0;0 and;;;0;;;;;;0;0 Design;;;0;;;;;;0;0 principles;William.S;IT;741012759;Upper;41012759;Upper;;0;;;;;;0;0 Saddle;;;0;;;;;;0;0 River;2009;QA7676063;Available;circulation;3;11200;lable;circulation;3;11200;;0;;;;;;0;0 Communication;;;0;;;;;;0;0 Thanks in advance, you're a life saver

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