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  • Binary Tree operator overloading and recursion

    - by furious.snail
    I was wondering how to overload the == operator for a binary tree to compare if two trees have identical data at same nodes. So far this is what I have: bool TreeType::operator==(const TreeType& otherTree) const { if((root == NULL) && (otherTree.root == NULL)) return true; //two null trees are equal else if((root != NULL) && (otherTree.root != NULL)) { return((root-info == otherTree.root-info) && //this part doesn't actually do anything recursively... //(root-left == otherTree.root-left) && //(root-right == otherTree.root-right)) } else return false; //one tree is null the other is not } I have a similar function that takes two TreeNode pointers as parameters but I've been stuck on how to convert it to this function.

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  • Limiting input to specified regexp with uppercase chars in IE

    - by pixelboy
    I'm trying to limit what our users will be able to type in inputs, using javascript/jquery. Problem is, I have to limit this to Uppercase chars only, and numbers. Here's what I coded previously : $(input).keydown(function(e){ if ($(input).attr("class")=="populationReference"){ var ValidPattern = /^[A-Z_0-9]*$/; var char = String.fromCharCode(e.charCode); if (!ValidPattern.test(char) && e.charCode!=0){ return false; e.preventDefault(); } } }); If Firefox supports charCode, IE doesn't. How then, could I test if the user is typing uppercase or lowercase characters ? Thanks for any help !

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  • getnameinfo specifies socklen_t

    - by bobby
    The 2nd arg for the getnameinfo prototype asks for a socklen_t type but sizeof uses size_t. So how can I get socklen_t ? Prototype: int getnameinfo(const struct sockaddr *restrict sa, socklen_t salen, char *restrict node, socklen_t nodelen, char *restrict service, socklen_t servicelen, int flags); Example: struct sockaddr_in SIN; memset(&SIN, 0, sizeof(SIN)); // This should also be socklen_t ? SIN.sin_family = AF_INET; SIN.sin_addr.s_addr = inet_addr(IP); SIN.sin_port = 0; getnameinfo((struct sockaddr *)&SIN, sizeof(SIN) /* socklen_t */, BUFFER, NI_MAXHOST, NULL, 0, 0);

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  • C++ - Opening a file inside a function using fopen. (Noob problem)

    - by Josh
    I am using Visual Studio 2005 (C++). I am passing a string into a function as a char array. I want to open the file passed in as a parameter and use it. I know my code works to an extent, because if I hardcode the filename as the first parameter it works perfectly. I do notice if I look at the value as a watch, the value includes the address aside the string literal. I have tried passing in the filename as a pointer, but it then complains about type conversion with __w64. As I said before it works fine with "filename.txt" in place of fileName. I am stumped. void read(char fileName[50],int destArray[MAX_R][MAX_C],int demSize[2]) { int rows=0; int cols=0; int row=0; int col=0; FILE * f = fopen(fileName,"r"); ...

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  • union marshalling issue in C#

    - by senthil
    I have union inside structure and the structure looks like struct tDeviceProperty { DWORD Tag; DWORD Size; union _DP value; }; typedef union _DP { short int i; LONG l; ULONG ul; float flt; double dbl; BOOL b; double at; FILETIME ft; LPSTR lpszA; LPWSTR lpszW; LARGE_INTEGER li; struct tBinary bin; BYTE reserved[40]; } __UDP; struct tBinary { ULONG size; BYTE * bin; }; from the tBinary structure bin has to be converted to tImage (structure is given below) struct tImage { DWORD x; DWORD y; DWORD z; DWORD Resolution; DWORD type; DWORD ID; diccid_t SourceID; const void *buffer; const char *Info; const char *UserImageID; }; to use the same in c# I have done marshaling but not giving proper values when converting the pointer to structure. The C# code is follows, tBinary tBin = new tBinary(); IntPtr tBinbuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(tBin)); Marshal.StructureToPtr(tBin.bin, tBinbuffer, false); tDeviceProperty tDevice = new tDeviceProperty(); tDevice.bin = tBinbuffer; IntPtr tDevicebuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(tDevice)); Marshal.StructureToPtr(tDevice.bin, tDevicebuffer, false); Battary tbatt = new Battary(); tbatt.value = tDevicebuffer; IntPtr tbattbuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(tbatt)); Marshal.StructureToPtr(tbatt.value, tbattbuffer, false); result = GetDeviceProperty(ref tbattbuffer); Battary v = (Battary)Marshal.PtrToStructure(tbattbuffer, typeof(Battary)); tDeviceProperty v2 = (tDeviceProperty)Marshal.PtrToStructure(tDevicebuffer, typeof(tDeviceProperty)); tBinary v3 = (tBinary)Marshal.PtrToStructure(tBinbuffer, typeof(tBinary));

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  • Where to split a string literal

    - by quinmars
    Every time I have to split a long string literal into two (or more) pieces, because it does not fit into a single line, I have to decide if I split the text before or after a space. For example: const char * long_text1 = "This is a long text, which does not fit " "in one line"; /* or */ const char * long_text2 = "This is a long text, which does not fit" " in one line"; I tend to use the first way, but I do not have a real reason for it. So I wonder is there any advantage to favor one of them? I know this questions tend to be coding style question, but that's not my intend. I only want to know if there is a convincing reason why one of those two ways might be preferable.

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  • Using read() directly into a C++ std:vector

    - by Joe
    I'm wrapping up user space linux socket functionality in some C++ for an embedded system (yes, this is probably reinventing the wheel again). I want to offer a read and write implementation using a vector. Doing the write is pretty easy, I can just pass &myvec[0] and avoid unnecessary copying. I'd like to do the same and read directly into a vector, rather than reading into a char buffer then copying all that into a newly created vector. Now, I know how much data I want to read, and I can allocate appropriately (vec.reserve). I can also read into &myvec[0], though this is probably a VERY BAD IDEA. Obviously doing this doesn't allow myvec.size to return anything sensible. Is there any way of doing this that 1) Doesn't completely feel yucky from a safety/C++ perspective and 2) Doesn't involve two copies of the data block - once from kernel to user space and once from a C char * style buffer into a C++ vector. Any thoughts collective?

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  • [C] Signed Hexadecimal string to long int function

    - by Ben
    I am trying to convert a 24bit Hexadecimal string (6 characters) signed in two's complement to a long int in C. This is the function I have come up with: long int hex2li (char string[]) { char *pEnd; long int result = strtol (string, &pEnd, 16); if (strcmp (pEnd, "") == 0) { if (toupper (string[0]) == 'F') { return result - 16777216; } else { return result; } } return LONG_MIN; } Is it valid? Is there a better way of doing this?

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  • Can I mix compile time string comparison with MPL templates?

    - by Negative Zero
    I got this compile time string comparison from another thread using constexpr and C++11 (http://stackoverflow.com/questions/5721813/compile-time-assert-for-string-equality). It works with constant strings like "OK" constexpr bool isequal(char const *one, char const *two) { return (*one && *two) ? (*one == *two && isequal(one + 1, two + 1)) : (!*one && !*two); } I am trying to use it in the following context: static_assert(isequal(boost::mpl::c_str<boost::mpl::string<'ak'>>::value, "ak"), "should not fail"); But it gives me an compilation error of static_assert expression is not an constant integral expression. Can I do this?

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  • alternative to strdup

    - by Alexander
    I am using strdup here to copy the value of the parameter name into nm in the constructor... is there an alternative of achieving the same result without using strdup and without using the C++ STL library and using the keyword new instead? Book::Book(const char *name, int thickness, int weight):nm(NULL), thck(thickness), wght(weight){ if(name) nm = strdup(name); } class Book { private: char* nm; .......... ............ .......... ........... };

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  • How to listen for file system changes MAC - kFSEventStreamCreateFlagWatchRoot

    - by Cocoa Newbie
    Hi All, I am listening for Directory and disk changes in a COCOA project using FSEvents. I need to get events when a root folder is renamed or deleted. So, I passed kFSEventStreamCreateFlagWatchRoot while creating the FSEventStream.But even if I delete or rename the root folder I am not getting corresponding FSEventStreamEventFlags. Any idea what could possibly be the issue. I am listening for changes in a USB mounted device. I used both FSEventStreamCreate and FSEventStreamCreateRelativeToDevice. One thing I notices is when I try with FSEventStreamCreate I get the following error message while creating FSEventStream: (CarbonCore.framework) FSEventStreamCreate: watch_all_parents: error trying to add kqueue for fd 7 (/Volumes/NO NAME; Operation not supported) But with FSEventStreamCreateRelativeToDevice there are no errors but still not getting kFSEventStreamEventFlagRootChanged in event flags. Also, while creation using FSEventStreamCreateRelativeToDevice apple say's if I want to listen to root path changes pass emty string "". But I am not able to listen to root path changes by passing empty string. But when I pass "/" it works. But even for "/" I do not get any proper FSEventStreamEventFlags. I am pasting the code here: -(void) subscribeFileSystemChanges:(NSString*) path { PRINT_FUNCTION_BEGIN; // if already subscribed then unsubscribe if (stream) { FSEventStreamStop(stream); FSEventStreamInvalidate(stream); /* will remove from runloop */ FSEventStreamRelease(stream); } FSEventStreamContext cntxt = {0}; cntxt.info = self; CFArrayRef pathsToWatch = CFArrayCreate(NULL, (const void**)&path, 1, NULL); stream = FSEventStreamCreate(NULL, &feCallback, &cntxt, pathsToWatch, kFSEventStreamEventIdSinceNow, 1, kFSEventStreamCreateFlagWatchRoot ); FSEventStreamScheduleWithRunLoop(stream, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode); FSEventStreamStart(stream); } call back function: static void feCallback(ConstFSEventStreamRef streamRef, void* pClientCallBackInfo, size_t numEvents, void* pEventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[]) {? char** ppPaths = (char**)pEventPaths; int i; for (i = 0; i < numEvents; i++) { NSLog(@"Event Flags %lu Event Id %llu", eventFlags[i], eventIds[i]); NSLog(@"Path changed: %@", [NSString stringWithUTF8String:ppPaths[i]]); } } Thanks a lot in advance.

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  • newline character on text area

    - by Prady
    I have a custom field called Current_Address__c which is of datatype textarea. I need to populate this field in the format below. ie a newline char after street and another newline after zip. street City state Zip Country The values of city state zip country etc are been taken from contact object. I dont want to use this as a formula field. So i need to populate it in my controller and display it on my VF page. I am trying to add a newline char by using the code below this.customobj.Current_Address__c = currentStreet + '\\n ' + currentCity + ' ' + currentState + ' ' + currentZIP + '\\n ' + currentCountry ; i had also used \n instead of \n. It still show the field in one line instead of 3 lines

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  • c99 goto past initialization

    - by R Samuel Klatchko
    While debugging a crash, I came across this issue in some code: int func() { char *p1 = malloc(...); if (p1 == NULL) goto err_exit; char *p2 = malloc(...); if (p2 == NULL) goto err_exit; ... err_exit: free(p2); free(p1); return -1; } The problem occurs when the first malloc fails. Because we jump across the initialization of p2, it contains random data and the call to free(p2) can crash. I would expect/hope that this would be treated the same way as in C++ where the compiler does not allow a goto to jump across an initialization. My question: is jumping across an initialization allowed by the standard or is this a bug in gcc's implementation of c99?

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  • GWT AbstractColumnDefinition (Need to add style to certain Columns)

    - by Mario
    I have a column Definition for each colume that extends AbstractColumnDefinition these columns are put in a DefaultTableDefinition. example: NAME | SIZE | RES | DELETE | this style (AT THE END OF THE PAGE ) is added to the column names if you notice all of them are with a cursor pointer , meaning a hand shows up when i hover above each one. my question is would I be able to remove the coursor for delete or in general for a certain column and keeping it for another one .. i tried to do that with each column Definition but there is no such thing as remove or addstyle even to like put my own style. THANK YOU .gwt-ScrollTable .headerTable td { border-bottom:1px solid black; border-left:1px solid #CCCCCC; border-right:1px solid #CCCCCC; cursor:pointer; vertical-align:bottom; }

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  • SQL Server Conditional Mailing Address Formatting

    - by Rob Packwood
    I have the following SQL to format a US address into each line for a mailing address but it is rather ugly. Is there a better way to solve this problem or does it have to be this ugly? declare @NL varchar(2); set @NL = char(13) + char(10); select case when rtrim(coalesce(AttentionLine,'') ) != '' then rtrim(AttentionLine ) + @NL else '' end + case when rtrim(coalesce(Recipient,'') ) != '' then rtrim(Recipient ) + @NL else '' end + case when rtrim(coalesce(AddlAddrLine,'') ) != '' then rtrim(AddlAddrLine ) + @NL else '' end + case when rtrim(coalesce(DeliveryAddr,'') ) != '' then rtrim(DeliveryAddr ) + @NL else '' end + case when rtrim(coalesce(LastLine,'') ) != '' then rtrim(LastLine ) + @NL else '' end + case when rtrim(coalesce(Country,'') ) != '' then rtrim(Country ) + @NL else '' end as FormattedMailingAddress from Address where Id = 1

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  • Need help configuring SQL Server CE connections string in Fluent NHibernate

    - by Yoav
    Hi, I'm trying to return a session factory using this code: return Fluently.Configure() .Database(MsSqlCeConfiguration.Standard.ShowSql().ConnectionString(path)) .Mappings(m => m.FluentMappings.AddFromAssemblyOf<Project>()) .BuildSessionFactory(); Path is the full path to an .sdf file. And get this exception: System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0. at System.Data.SqlServerCe.ConStringUtil.GetKeyValuePair(Char[] connectionString, Int32 currentPosition, String& key, Char[] valuebuf, Int32& vallength, Boolean& isempty) What am I doing wrong?

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  • C/C++ - Convert 24-bit signed integer to float

    - by e-t172
    I'm programming in C++. I need to convert a 24-bit signed integer (stored in a 3-byte array) to float (normalizing to [-1.0,1.0]). The platform is MSVC++ on x86 (which means the input is little-endian). I tried this: float convert(const unsigned char* src) { int i = src[2]; i = (i << 8) | src[1]; i = (i << 8) | src[0]; const float Q = 2.0 / ((1 << 24) - 1.0); return (i + 0.5) * Q; } I'm not entirely sure, but it seems the results I'm getting from this code are incorrect. So, is my code wrong and if so, why?

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  • Glib convert epoch time to string.

    - by PP
    I am using glibs functions to convert epoch time to string as follows. But each time it is giving me some random time. //Convert Time in string. GDate *date = g_date_new_julian(timestampsecs); gchar date_string[50]; g_date_strftime(date_string, 50, (const gchar*)"%a, %I:%M %p", (const GDate*)date); printf("Date String [%s]\n", date_string ); Why this might be happening? am i missing anything? Thanks, PP.

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  • how to get the type of a deferred template parameter

    - by smerlin
    Is there a way to get the defered type of a class template parameter ? template <class TPtr> struct foo { typedef TPtr ptr_type; typedef ??? element_type; /* shall be the type of a deferred TPtr*/ }; so foo<const char*>::element_type results in const char, and foo<std::vector<int>::iterator_type>::element_type results in int. i am aware of that i can use the value_type typedef for c++ iterators (like std::vector<int>::iterator_type::value_type), but raw pointers havent got a value_type typedef, so i am out of luck there.

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  • global std::unordered_map com server init problems

    - by PrettyFlower
    I want to have a static global std::unordered_map in the cpp of my entry point for my COM server. relevant header code: typedef unordered_map<HWND,IMyInterface*> MyMapType; relevant body: static MyMapType MyMap; void MyFunction(HWND hWnd, IMyInterface* pObj){ MyMap[HWND] = pObj; } HINSTANCE g_hInstModule = NULL; BOOL WINAPI DllMain ( __in HINSTANCE hInstDLL, __in DWORD fdwReason, __in LPVOID lpvReserved ) { if( fdwReason == DLL_PROCESS_ATTACH ) { g_hInstModule = hInstDLL; return true; } else if( fdwReason == DLL_PROCESS_DETACH ) { return true; } return false; } MyCoClass::MyCoClass() { DRM_Refcount = 1; } HRESULT STDMETHODCALLTYPE MyCoClass::InitMyCoClass() { CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); //replace with make window code MyFunction(hWnd,ISomeInterface); return S_OK; } The only way I can get this to work is be making a map_type pointer and creating an instance of map_type on the heap and pointing at it with the global pointer. :/ WHY?

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  • when to use strncpy or memmove

    - by robUK
    Hello, gcc 4.4.4 c89 I have always used strncpy to copy strings. I have never really used memmove or memcpy very much. However, I am just wondering when would you decide whether to use strncpy, memmove, or memcpy? The code I am writing is for a client/server application. In the documentation they use bcopy. However, could I do the same with the others? bcopy((char*)server->h_addr, (char*)&serv_addr.sin_addr.s_addr, server->h_length); Many thanks,

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  • Why C++ virtual function defined in header may not be compiled and linked in vtable?

    - by 0xDEAD BEEF
    Situation is following. I have shared library, which contains class definition - QueueClass : IClassInterface { virtual void LOL() { do some magic} } My shared library initialize class member QueueClass *globalMember = new QueueClass(); My share library export C function which returns pointer to globalMember - void * getGlobalMember(void) { return globalMember;} My application uses globalMember like this ((IClassInterface*)getGlobalMember())->LOL(); Now the very uber stuff - if i do not reference LOL from shared library, then LOL is not linked in and calling it from application raises exception. Reason - VTABLE contains nul in place of pointer to LOL() function. When i move LOL() definition from .h file to .cpp, suddenly it appears in VTABLE and everything works just great. What explains this behavior?! (gcc compiler + ARM architecture_)

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  • Threading and pcap issues.

    - by cftmon
    I have a GUI program that allows a user a scan a network, the issue is that when the pcap_loop function is called, my GUI program becomes unresponsive.(the pcap_loop blocks the current thread). When i try to use pthreads, i got a SIGSEGV fault at the pcap_loop function.Why?It's as if the thread can't see the procPacket function itself. void procPacket(u_char *arg, const struct pcap_pkthdr *pkthdr, const u_char *packet) { //show packets here } void* pcapLooper(void* param) { pcap_t* handler = (pcap_t*) param; pcap_loop(handler, 900 ,procPacket, NULL ); } //some function that runs when a button is pressed //handler has been opened through pcap_open_live pthread_t scanner; int t = pthread_create(&scanner,NULL,&pcapLooper, &handler ); if(t) { std::cout << "failed" << std::endl; } pthread_join(scanner,NULL); //do other stuff.

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  • JNI cached jclass global reference variables being garbage collected?

    - by bubbadoughball
    I'm working in the JNI Invocation API, calling into Java from C. I have some upfront initialization to cache 30+ Java classes into global references. The results of FindClass are passed into NewGlobalRef to acquire a global reference to the class. I'm caching these class variables to reuse them later. I have 30+ global references to classes (and 30+ global methodIDs for the class constructors). In the following sample, I've removed exception handling as well as JNI invocation for the purpose of shortening the code snippet. My working code has exception checks after every JNI call and I'm running with -Xcheck:jni. Here's the snippet: jclass aClass; jclass bClass; jmethodID aCtor; jmethodID bCtor; void getGlobalRef(const char* clazz, jclass* globalClass) { jclass local = (*jenv)->FindClass(jenv,clazz); if (local) { *globalClass = (jclass) (*jenv)->NewGlobalRef(jenv,local); (*jenv)->DeleteLocalRef(jenv,local); } } methodID getMethodID(jclass clazz, const char* method, const char* sig) { return (*jenv)->GetMethodID(jenv,clazz,method,sig); } void initializeJNI() { getGlobalRef("MyProj/Testclass1", &aclass); getGlobalRef("MyProj/Testclass2", &bclass); . . aCtor = getMethodID(aclass,"<init>","()V"); bCtor = getMethodID(bclass,"<init>","(I)V"); } The initializeJNI() function sets the global references for jclasses and method IDs for constructors as well as some jfieldID's and some initialization of C data structures. After initialization, when I call into a JNI function using some of the cached jclasses and ctor jmethodIDs, I get a bad global or local reference calling reported from the -Xcheck:jni. In gdb, I break at the last line of initializeJNI(), and print all jclasses and jmethodIDs and the ones causing problems look to have been turned into garbage or garbage-collected (i.e. 0x00 or 0x06). Is it possible for global references to be gc'ed? Any suggestions?

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