Search Results

Search found 10366 results on 415 pages for 'const char pointer'.

Page 97/415 | < Previous Page | 93 94 95 96 97 98 99 100 101 102 103 104  | Next Page >

  • format specifier for short integer

    - by cateof
    I don't use correctly the format specifiers in C. A few lines of code: int main() { char dest[]="stack"; unsigned short val = 500; char c = 'a'; char* final = (char*) malloc(strlen(dest) + 6); snprintf(final, strlen(dest)+6, "%c%c%hd%c%c%s", c, c, val, c, c, dest); printf("%s\n", final); return 0; } I want my executable to print aa500aastack and not aa500aasta Why I am loosing 2 byte? What is the correct format specifier for an unsighed short integer? thanks.

    Read the article

  • Compilation errors calling find_if using a functor

    - by Jim Wong
    We are having a bit of trouble using find_if to search a vector of pairs for an entry in which the first element of the pair matches a particular value. To make this work, we have defined a trivial functor whose operator() takes a pair as input and compares the first entry against a string. Unfortunately, when we actually add a call to find_if using an instance of our functor constructed using a temporary string value, the compiler produces a raft of error messages. Oddly (to me, anyway), if we replace the temporary with a string that we've created on the stack, things seem to work. Here's what the code (including both versions) looks like: typedef std::pair<std::string, std::string> MyPair; typedef std::vector<MyPair> MyVector; struct MyFunctor: std::unary_function <const MyPair&, bool> { explicit MyFunctor(const std::string& val) : m_val(val) {} bool operator() (const MyPair& p) { return p.first == m_val; } const std::string m_val; }; bool f(const char* s) { MyFunctor f(std::string(s)); // ERROR // std::string str(s); // MyFunctor f(str); // OK MyVector vec; MyVector::const_iterator i = std::find_if(vec.begin(), vec.end(), f); return i != vec.end(); } And here's what the most interesting error message looks like: /usr/include/c++/4.2.1/bits/stl_algo.h:260: error: conversion from ‘std::pair, std::allocator , std::basic_string, std::allocator ’ to non-scalar type ‘std::string’ requested Because we have a workaround, we're mostly curious as to why the first form causes problems. I'm sure we're missing something, but we haven't been able to figure out what it is.

    Read the article

  • How to set a keybinding which is valid in all modes in Emacs

    - by AnotherEmacsLearner
    Hi, I've configured my emacs to use M-j as backward-char by (global-set-key (kbd "M-j") 'backward-char) ; was indent-new-comment-line in my .emacs file. This works fine in many modes (text/org/lisp). But in c++-mode & php-mode it is bound to the default c-indent-new-comment-line How can I bind M-j to use backward-char in these modes too. And in general for ALL modes. Thanks, AnotherEmacsLearner

    Read the article

  • C++0x rvalue references - lvalues-rvalue binding

    - by Doug
    This is a follow-on question to http://stackoverflow.com/questions/2748866/c0x-rvalue-references-and-temporaries In the previous question, I asked how this code should work: void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } It seems that the move overload should probably be called because of the implicit temporary, and this happens in GCC but not MSVC (or the EDG front-end used in MSVC's Intellisense). What about this code? void f(std::string &&); //NB: No const string & overload supplied void g1(const char * arg) { f(arg); } void g2(const std::string & arg) { f(arg); } It seems that, based on the answers to my previous question that function g1 is legal (and is accepted by GCC 4.3-4.5, but not by MSVC). However, GCC and MSVC both reject g2 because of clause 13.3.3.1.4/3, which prohibits lvalues from binding to rvalue ref arguments. I understand the rationale behind this - it is explained in N2831 "Fixing a safety problem with rvalue references". I also think that GCC is probably implementing this clause as intended by the authors of that paper, because the original patch to GCC was written by one of the authors (Doug Gregor). However, I don't this is quite intuitive. To me, (a) a const string & is conceptually closer to a string && than a const char *, and (b) the compiler could create a temporary string in g2, as if it were written like this: void g2(const std::string & arg) { f(std::string(arg)); } Indeed, sometimes the copy constructor is considered to be an implicit conversion operator. Syntactically, this is suggested by the form of a copy constructor, and the standard even mentions this specifically in clause 13.3.3.1.2/4, where the copy constructor for derived-base conversions is given a higher conversion rank than other implicit conversions: A conversion of an expression of class type to the same class type is given Exact Match rank, and a conversion of an expression of class type to a base class of that type is given Conversion rank, in spite of the fact that a copy/move constructor (i.e., a user-defined conversion function) is called for those cases. (I assume this is used when passing a derived class to a function like void h(Base), which takes a base class by value.) Motivation My motivation for asking this is something like the question asked in http://stackoverflow.com/questions/2696156/how-to-reduce-redundant-code-when-adding-new-c0x-rvalue-reference-operator-over ("How to reduce redundant code when adding new c++0x rvalue reference operator overloads"). If you have a function that accepts a number of potentially-moveable arguments, and would move them if it can (e.g. a factory function/constructor: Object create_object(string, vector<string>, string) or the like), and want to move or copy each argument as appropriate, you quickly start writing a lot of code. If the argument types are movable, then one could just write one version that accepts the arguments by value, as above. But if the arguments are (legacy) non-movable-but-swappable classes a la C++03, and you can't change them, then writing rvalue reference overloads is more efficient. So if lvalues did bind to rvalues via an implicit copy, then you could write just one overload like create_object(legacy_string &&, legacy_vector<legacy_string> &&, legacy_string &&) and it would more or less work like providing all the combinations of rvalue/lvalue reference overloads - actual arguments that were lvalues would get copied and then bound to the arguments, actual arguments that were rvalues would get directly bound. Questions My questions are then: Is this a valid interpretation of the standard? It seems that it's not the conventional or intended one, at any rate. Does it make intuitive sense? Is there a problem with this idea that I"m not seeing? It seems like you could get copies being quietly created when that's not exactly expected, but that's the status quo in places in C++03 anyway. Also, it would make some overloads viable when they're currently not, but I don't see it being a problem in practice. Is this a significant enough improvement that it would be worth making e.g. an experimental patch for GCC?

    Read the article

  • MS Detours Library, detouring non win api function

    - by flavour404
    Hi, I want to use the windows detours library to detour a non win api function. The function is part of the Qt library (QtGui4.dll). I am wondering how I would set up the function signature for : void QPainter::drawText ( const QPointF & position, const QString & text ) I had a go with this and it received my usual share of errors, a little explanation of requirements would be interesting as well: void (QPainter * real_drawText)(const QPointF & position, const QString & text) = drawText This is what they look like for TextOut, under the windows API: BOOL (WINAPI * Real_TextOut)(HDC a0, int a1, int a2, LPCWSTR a3, int a4) = TextOutW; BOOL WINAPI Mine_TextOut(HDC hdc,int X,int Y,LPCWSTR text,int textLen) { BOOL rv = Real_TextOut(hdc, X, Y, text, textLen); HWND hWindow = WindowFromDC(hdc); SendTextMessage(hWindow, text); return rv; } Thanks.

    Read the article

  • (C++) Linking with namespaces causes duplicate symbol error

    - by user577072
    Hello. For the past few days, I have been trying to figure out how to link the files for a CLI gaming project I have been working on. There are two halves of the project, the Client and the Server code. The client needs two libraries I've made. The first is a general purpose game board. This is split between GameEngine.h and GameEngine.cpp. The header file looks something like this namespace gfdGaming { // struct sqr_size { // Index x; // Index y; // }; typedef struct { Index x, y; } sqr_size; const sqr_size sPos = {1, 1}; sqr_size sqr(Index x, Index y); sqr_size ePos; class board { // Prototypes / declarations for the class } } And the CPP file is just giving everything content #include "GameEngine.h" type gfdGaming::board::functions The client also has game-specific code (in this case, TicTacToe) split into declarations and definitions (TTT.h, Client.cpp). TTT.h is basically #include "GameEngine.h" #define TTTtar "localhost" #define TTTport 2886 using namespace gfdGaming; void* turnHandler(void*); namespace nsTicTacToe { GFDCON gfd; const char X = 'X'; const char O = 'O'; string MPhostname, mySID; board TTTboard; bool PlayerIsX = true, isMyTurn; char Player = X, Player2 = O; int recon(string* datHolder = NULL, bool force = false); void initMP(bool create = false, string hn = TTTtar); void init(); bool isTie(); int turnPlayer(Index loc, char lSym = Player); bool checkWin(char sym = Player); int mainloop(); int mainloopMP(); }; // NS I made the decision to put this in a namespace to group it instead of a class because there are some parts that would not work well in OOP, and it's much easier to implement later on. I have had trouble linking the client in the past, but this setup seems to work. My server is also split into two files, Server.h and Server.cpp. Server.h contains exactly: #include "../TicTacToe/TTT.h" // Server needs a full copy of TicTacToe code class TTTserv; struct TTTachievement_requirement { Index id; Index loc; bool inUse; }; struct TTTachievement_t { Index id; bool achieved; bool AND, inSameGame; bool inUse; bool (*lHandler)(TTTserv*); char mustBeSym; int mustBePlayer; string name, description; TTTachievement_requirement steps[safearray(8*8)]; }; class achievement_core_t : public GfdOogleTech { public: // May be shifted to private TTTachievement_t list[safearray(8*8)]; public: achievement_core_t(); int insert(string name, string d, bool samegame, bool lAnd, int lSteps[8*8], int mbP=0, char mbS=0); }; struct TTTplayer_t { Index id; bool inUse; string ip, sessionID; char sym; int desc; TTTachievement_t Ding[8*8]; }; struct TTTgame_t { TTTplayer_t Player[safearray(2)]; TTTplayer_t Spectator; achievement_core_t achievement_core; Index cTurn, players; port_t roomLoc; bool inGame, Xused, Oused, newEvent; }; class TTTserv : public gSserver { TTTgame_t Game; TTTplayer_t *cPlayer; port_t conPort; public: achievement_core_t *achiev; thread threads[8]; int parseit(string tDat, string tsIP); Index conCount; int parseit(string tDat, int tlUser, TTTplayer_t** retval); private: int parseProto(string dat, string sIP); int parseProto(string dat, int lUser); int cycleTurn(); void setup(port_t lPort = 0, bool complete = false); public: int newEvent; TTTserv(port_t tlPort = TTTport, bool tcomplete = true); TTTplayer_t* userDC(Index id, Index force = false); int sendToPlayers(string dat, bool asMSG = false); int mainLoop(volatile bool *play); }; // Other void* userHandler(void*); void* handleUser(void*); And in the CPP file I include Server.h and provide main() and the contents of all functions previously declared. Now to the problem at hand I am having issues when linking my server. More specifically, I get a duplicate symbol error for every variable in nsTicTacToe (and possibly in gfdGaming as well). Since I need the TicTacToe functions, I link Client.cpp ( without main() ) when building the server ld: duplicate symbol nsTicTacToe::PlayerIsX in Client.o and Server.o collect2: ld returned 1 exit status Command /Developer/usr/bin/g++-4.2 failed with exit code 1 It stops once a problem is encountered, but if PlayerIsX is removed / changed temporarily than another variable causes an error Essentially, I am looking for any advice on how to better organize my code to hopefully fix these errors. Disclaimers: -I apologize in advance if I provided too much or too little information, as it is my first time posting -I have tried using static and extern to fix these problems, but apparently those are not what I need Thank you to anyone who takes the time to read all of this and respond =)

    Read the article

  • How to programatically read native DLL imports in C#?

    - by Eric
    The large hunk of C# code below is intended to print the imports of a native DLL. I copied it from from this link and modified it very slightly, just to use LoadLibraryEx as Mike Woodring does here. I find that when I call the Foo.Test method with the original example's target, MSCOREE.DLL, it prints all the imports fine. But when I use other dlls like GDI32.DLL or WSOCK32.DLL the imports do not get printed. What's missing from this code that would let it print all the imports as, for example, DUMPBIN.EXE does? (Is there a hint I'm not grokking in the original comment that says, "using mscoree.dll as an example as it doesnt export any thing"?) Here's the extract that just shows how it's being invoked: public static void Test() { // WORKS: var path = @"c:\windows\system32\mscoree.dll"; // NO ERRORS, BUT NO IMPORTS PRINTED EITHER: //var path = @"c:\windows\system32\gdi32.dll"; //var path = @"c:\windows\system32\wsock32.dll"; var hLib = LoadLibraryEx(path, 0, DONT_RESOLVE_DLL_REFERENCES | LOAD_IGNORE_CODE_AUTHZ_LEVEL); TestImports(hLib, true); } And here is the whole code example: namespace PETest2 { [StructLayout(LayoutKind.Explicit)] public unsafe struct IMAGE_IMPORT_BY_NAME { [FieldOffset(0)] public ushort Hint; [FieldOffset(2)] public fixed char Name[1]; } [StructLayout(LayoutKind.Explicit)] public struct IMAGE_IMPORT_DESCRIPTOR { #region union /// <summary> /// CSharp doesnt really support unions, but they can be emulated by a field offset 0 /// </summary> [FieldOffset(0)] public uint Characteristics; // 0 for terminating null import descriptor [FieldOffset(0)] public uint OriginalFirstThunk; // RVA to original unbound IAT (PIMAGE_THUNK_DATA) #endregion [FieldOffset(4)] public uint TimeDateStamp; [FieldOffset(8)] public uint ForwarderChain; [FieldOffset(12)] public uint Name; [FieldOffset(16)] public uint FirstThunk; } [StructLayout(LayoutKind.Explicit)] public struct THUNK_DATA { [FieldOffset(0)] public uint ForwarderString; // PBYTE [FieldOffset(4)] public uint Function; // PDWORD [FieldOffset(8)] public uint Ordinal; [FieldOffset(12)] public uint AddressOfData; // PIMAGE_IMPORT_BY_NAME } public unsafe class Interop { #region Public Constants public static readonly ushort IMAGE_DIRECTORY_ENTRY_IMPORT = 1; #endregion #region Private Constants #region CallingConvention CALLING_CONVENTION /// <summary> /// Specifies the calling convention. /// </summary> /// <remarks> /// Specifies <see cref="CallingConvention.Winapi" /> for Windows to /// indicate that the default should be used. /// </remarks> private const CallingConvention CALLING_CONVENTION = CallingConvention.Winapi; #endregion CallingConvention CALLING_CONVENTION #region IMPORT DLL FUNCTIONS private const string KERNEL_DLL = "kernel32"; private const string DBGHELP_DLL = "Dbghelp"; #endregion #endregion Private Constants [DllImport(KERNEL_DLL, CallingConvention = CALLING_CONVENTION, EntryPoint = "GetModuleHandleA"), SuppressUnmanagedCodeSecurity] public static extern void* GetModuleHandleA(/*IN*/ char* lpModuleName); [DllImport(KERNEL_DLL, CallingConvention = CALLING_CONVENTION, EntryPoint = "GetModuleHandleW"), SuppressUnmanagedCodeSecurity] public static extern void* GetModuleHandleW(/*IN*/ char* lpModuleName); [DllImport(KERNEL_DLL, CallingConvention = CALLING_CONVENTION, EntryPoint = "IsBadReadPtr"), SuppressUnmanagedCodeSecurity] public static extern bool IsBadReadPtr(void* lpBase, uint ucb); [DllImport(DBGHELP_DLL, CallingConvention = CALLING_CONVENTION, EntryPoint = "ImageDirectoryEntryToData"), SuppressUnmanagedCodeSecurity] public static extern void* ImageDirectoryEntryToData(void* Base, bool MappedAsImage, ushort DirectoryEntry, out uint Size); } static class Foo { // From winbase.h in the Win32 platform SDK. // const uint DONT_RESOLVE_DLL_REFERENCES = 0x00000001; const uint LOAD_IGNORE_CODE_AUTHZ_LEVEL = 0x00000010; [DllImport("kernel32.dll"), SuppressUnmanagedCodeSecurity] static extern uint LoadLibraryEx(string fileName, uint notUsedMustBeZero, uint flags); public static void Test() { //var path = @"c:\windows\system32\mscoree.dll"; //var path = @"c:\windows\system32\gdi32.dll"; var path = @"c:\windows\system32\wsock32.dll"; var hLib = LoadLibraryEx(path, 0, DONT_RESOLVE_DLL_REFERENCES | LOAD_IGNORE_CODE_AUTHZ_LEVEL); TestImports(hLib, true); } // using mscoree.dll as an example as it doesnt export any thing // so nothing shows up if you use your own module. // and the only none delayload in mscoree.dll is the Kernel32.dll private static void TestImports( uint hLib, bool mappedAsImage ) { unsafe { //fixed (char* pszModule = "mscoree.dll") { //void* hMod = Interop.GetModuleHandleW(pszModule); void* hMod = (void*)hLib; uint size = 0; uint BaseAddress = (uint)hMod; if (hMod != null) { Console.WriteLine("Got handle"); IMAGE_IMPORT_DESCRIPTOR* pIID = (IMAGE_IMPORT_DESCRIPTOR*)Interop.ImageDirectoryEntryToData((void*)hMod, mappedAsImage, Interop.IMAGE_DIRECTORY_ENTRY_IMPORT, out size); if (pIID != null) { Console.WriteLine("Got Image Import Descriptor"); while (!Interop.IsBadReadPtr((void*)pIID->OriginalFirstThunk, (uint)size)) { try { char* szName = (char*)(BaseAddress + pIID->Name); string name = Marshal.PtrToStringAnsi((IntPtr)szName); Console.WriteLine("pIID->Name = {0} BaseAddress - {1}", name, (uint)BaseAddress); THUNK_DATA* pThunkOrg = (THUNK_DATA*)(BaseAddress + pIID->OriginalFirstThunk); while (!Interop.IsBadReadPtr((void*)pThunkOrg->AddressOfData, 4U)) { char* szImportName; uint Ord; if ((pThunkOrg->Ordinal & 0x80000000) > 0) { Ord = pThunkOrg->Ordinal & 0xffff; Console.WriteLine("imports ({0}).Ordinal{1} - Address: {2}", name, Ord, pThunkOrg->Function); } else { IMAGE_IMPORT_BY_NAME* pIBN = (IMAGE_IMPORT_BY_NAME*)(BaseAddress + pThunkOrg->AddressOfData); if (!Interop.IsBadReadPtr((void*)pIBN, (uint)sizeof(IMAGE_IMPORT_BY_NAME))) { Ord = pIBN->Hint; szImportName = (char*)pIBN->Name; string sImportName = Marshal.PtrToStringAnsi((IntPtr)szImportName); // yes i know i am a lazy ass Console.WriteLine("imports ({0}).{1}@{2} - Address: {3}", name, sImportName, Ord, pThunkOrg->Function); } else { Console.WriteLine("Bad ReadPtr Detected or EOF on Imports"); break; } } pThunkOrg++; } } catch (AccessViolationException e) { Console.WriteLine("An Access violation occured\n" + "this seems to suggest the end of the imports section\n"); Console.WriteLine(e); } pIID++; } } } } } Console.WriteLine("Press Any Key To Continue......"); Console.ReadKey(); } }

    Read the article

  • Unable to locate the Bug

    - by tzenes
    I was recently on The Daily WTF when I came across this old post. In it the author mentions that one of the programmers changed this code: int main (int argc, char **argv) { int x; char data_string[15]; ... x = 2; strcpy(data_string,"data data data"); ... } To this code: int main (int argc, char **argv) { int x = 2; char data_string[15] = "data data data"; ... } The author goes on to mention: [the coder] changed every single variable to be initiated on the stack For the life of me I cannot see how this change could be harmful, and I am worried that it is a lapse in my C knowledge. What is the WTF?

    Read the article

  • Looking for marg_setValue fix in iPhoneOS

    - by John Smith
    I am trying to compile a library originally written for Cocoa. Things are good until it looks for the function marg_setValue(). It says there is a syntax error before char in marg_setValue(argumentList,argumentOffset,char,(char)lua_toboolean(state,luaArgument)); (it's talking about the third argument, not (char) ) I am trying to port LuaObjectiveCBridge to the iPhone. It has two choices, either using Runtime or Foundation. I have discovered there are some problems with foundation so I am trying runtime. But the compiler is not co-operating.

    Read the article

  • C Check Substring of a String C

    - by user69514
    I'm trying to check whether or not the second argument in my program is a substring of the first argument. The problem is that it only work if the substring starts with the same letter of the string. EDIT: It must be done in C, not C++. Sorry #include <stdio.h> #include <string.h> int my_strstr( char const *s, char const *sub ) { char const *ret = sub; while ( ret = strchr( ret, *sub ) ) { if ( strcmp( ++ret, sub+1 ) == 0 ) return 1; } return 0; } int main(int argc, char **argv){ if (argc != 3) { printf ("Usage: check <string one> <string two>\n"); } int result = my_strstr(argv[1], argv[2]); if(result == 1){ printf("%s is a substring of %s\n", argv[2], argv[1]); } else{ printf("%s is not a substring of %s\n", argv[2], argv[1]); } return 0; }

    Read the article

  • can javascript process binary data?

    - by Johnny
    admit me describe my questions in situation-oriented way: assume IE is still the dominate web browser(the firefox have document for binary processing): the XMLHttpRequest.responseText or XMLHttpRequest.responseXML in ie desire txt or xml/xhtml/html,but what about the server response the xmlHttprequest whith MIME TYPE application/octet ? would the response string all little than 256 ?(every char of that string < 256), thanks very much for a straight answer, i have no webserver env,so i don't know how to test it out. because use txt or xml have a issue of character set encode, and i don't know how to process #[[[CDDATA node of one encoded xml(ex : utf-8,ascii,gb18030) with javascript, when i getNodeText, does the docObj return me byte or decoded char ? if it was decoded char which according to the header indicated charSet in the httpresponse , it would be all wrong. to avoid mess up with charSet ,i would like the server to response octet data and force strings data to be encoded as utf-8 but another charSet in the binary format. if the response is octal, so i guess the browser would not try to decode the response"txt" does this weird? or miss understanding the fundamental things? EDIT: I believe the question is asking this: Can Javascript safely process strings that aren't encoded in Unicode? What are the problems with trying to do so? EDIT: no no no , i means if http-header: content-type is "application/octet" , would the ie try to decoded it as (16bits Unicode | ie local setting charset ) when i get XMLHttpRequestobj.responseText use javascript ? or it(ie) just wrap every single byte of the response body as a javascript string, then every char in that string little than or equal 256 (char<=256), am i talking Mars language? sadly, if i were Marsizen,i would come as tourist without fuzzy questions. however i am in a country which share at least one property with Mars : RED

    Read the article

  • Interop Structure: Should Unsigned Short be Mapped to byte[]?

    - by Ngu Soon Hui
    I have such a C++ structure: typedef struct _FILE_OP_BLOCK { unsigned short fid; // objective file ID unsigned short offset; // operating offset unsigned char len; // buffer length(update) // read length(read) unsigned char buff[MAX_BUFF_SIZE]; } FILE_OP_BLOCK; And now I want to map it in .Net. The tricky thing is that the I should pass a 2 byte array for fid, and integer for len, even though in C# fid is an unsigned short and len is an unsigned char I wonder whether my structure ( in C#) below is correct? public struct File_OP_Block { [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)] public byte[] fid; public ushort offset; public byte length; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 240)] public char[] buff; }

    Read the article

  • Struct Array Initialization and String Literals

    - by Christian Ammer
    Is following array initialization correct? I guess it is, but i'm not really sure if i can use const char* or if i better should use std::string. Beside the first question, do the char pointers point to memory segments of same sizes? struct qinfo { const char* name; int nr; }; qinfo queues[] = { {"QALARM", 1}, {"QTESTLONGNAME", 2}, {"QTEST2", 3}, {"QIEC", 4} };

    Read the article

  • using 'new' operator

    - by notLikeCpp
    I have simple task concerning 'new' operator. I need to create array of 10 chars and then input those chars using 'cin'. Should it look like this ? : char c = new char[10]; for(int i=0; i < 10; i++) { cin >> char[i] >> endl; }

    Read the article

  • quick java question

    - by j-unit-122
    private static char[] quicksort (char[] array , int left , int right) { if (left < right) { int p = partition(array , left, right); quicksort(array, left, p - 1 ); quicksort(array, p + 1 , right); } for (char i : array) System.out.print(i + ” ”); System.out.println(); return array; } private static int partition(char[] a, int left, int right) { char p = a[left]; int l = left + 1, r = right; while (l < r) { while (l < right && a[l] < p) l++; while (r > left && a[r] >= p) r--; if (l < r) { char temp = a[l]; a[l] = a[r]; a[r] = temp; } } a[left] = a[r]; a[r] = p; return r; } } hi guys just a quick question regarding the above coding, i know that the above coding returns the following B I G C O M P U T E R B C E G I M P U T O R B C E G I M P U T O R B C E G I M P U T O R B C E G I M P U T O R B C E G I M O P T U R B C E G I M O P R T U B C E G I M O P R T U B C E G I M O P R T U B C E G I M O P R T U B C E G I M O P R T U B C E G I M O P R T U B C E G I M O P R T U when the sequence BIGCOMPUTER is used but my question is can someone explain to me what is happening in the code and how? i know abit about the quick-sort algorithm but it doesnt seem to be the same in the above example.

    Read the article

  • Which header files are necessary to run this code snippet?

    - by httpinterpret
    It's from here,but fails when compiling: int main(int argc, char **argv) { struct hostent { char *h_name; // main name char **h_aliases; // alternative names (aliases) int h_addrtype; // address type (usually AF_INET) int h_length; // length of address (in octets) char **h_addr_list; // alternate addresses (in Network Byte Order) }; #define h_addr h_addr_list[0] // First address of h_addr_list. struct hostent *info_stackoverflow; int i = 0; info_stackoverflow = gethostbyname( "www.stackoverflow.com" ); printf("The IP address of %s is %s", info_stackoverflow->h_name, inet_ntoa( * ((struct in_addr *)info_stackoverflow->h_addr ))); /* aliases */ while( *(pc_ip->h_aliases + i) != NULL ) { printf("\n\tAlias: %s", *(pc_ip->h_aliases + i) ); i++; } }

    Read the article

  • how to check if internal storage file has any data

    - by user3720291
    public class Save extends Activity { int levels = 2; int data_block = 1024; //char[] data = new char[] {'0', '0'}; String blankval = "0"; String targetval = "0"; String temp; String tempwrite; String string = "null"; TextView tex1; TextView tex2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.save); Intent intent = getIntent(); Bundle b = intent.getExtras(); tex1 = (TextView) findViewById(R.id.textView1); tex2 = (TextView) findViewById(R.id.textView2); if(b!=null) { string =(String) b.get("string"); } loadprev(); save(); } public void save() { if (string.equals("Blank")) blankval = "1"; if (string.equals("Target")) targetval = "1"; temp = blankval + targetval; try { FileOutputStream fos = openFileOutput("data.gds", MODE_PRIVATE); fos.write(temp.getBytes()); fos.close(); } catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} tex1.setText(blankval); tex2.setText(targetval); } public void loadprev() { String final_data = ""; try { FileInputStream fis = openFileInput("data.gds"); InputStreamReader isr = new InputStreamReader(fis); char[] data = new char[data_block]; int size; while((size = isr.read(data))>0) { String read_data = String.copyValueOf(data, 0, size); final_data += read_data; data = new char[data_block]; } } catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} char[] tempread = final_data.toCharArray();; blankval = "" + tempread[0]; targetval = "" + tempread[1]; } } After much tinkering i have finally managed to get my save/load function to work, but it does have an error, pretty much i got it to work then i did a fresh reintall deleting data.gds, afterwards the save/load function crashes because the data.gds file has no previous values. can i use a if statment to check if data.gds has any values in it, if so how do i do it and if not, then what could i use instead?

    Read the article

  • Access violation using LocalAlloc()

    - by PaulH
    I have a Visual Studio 2008 Windows Mobile 6 C++ application that is using an API that requires the use of LocalAlloc(). To make my life easier, I created an implementation of a standard allocator that uses LocalAlloc() internally: /// Standard library allocator implementation using LocalAlloc and LocalReAlloc /// to create a dynamically-sized array. /// Memory allocated by this allocator is never deallocated. That is up to the /// user. template< class T, int max_allocations > class LocalAllocator { public: typedef T value_type; typedef size_t size_type; typedef ptrdiff_t difference_type; typedef T* pointer; typedef const T* const_pointer; typedef T& reference; typedef const T& const_reference; pointer address( reference r ) const { return &r; }; const_pointer address( const_reference r ) const { return &r; }; LocalAllocator() throw() : c_( NULL ) { }; /// Attempt to allocate a block of storage with enough space for n elements /// of type T. n>=1 && n<=max_allocations. /// If memory cannot be allocated, a std::bad_alloc() exception is thrown. pointer allocate( size_type n, const void* /*hint*/ = 0 ) { if( NULL == c_ ) { c_ = LocalAlloc( LPTR, sizeof( T ) * n ); } else { HLOCAL c = LocalReAlloc( c_, sizeof( T ) * n, LHND ); if( NULL == c ) LocalFree( c_ ); c_ = c; } if( NULL == c_ ) throw std::bad_alloc(); return reinterpret_cast< T* >( c_ ); }; /// Normally, this would release a block of previously allocated storage. /// Since that's not what we want, this function does nothing. void deallocate( pointer /*p*/, size_type /*n*/ ) { // no deallocation is performed. that is up to the user. }; /// maximum number of elements that can be allocated size_type max_size() const throw() { return max_allocations; }; private: /// current allocation point HLOCAL c_; }; // class LocalAllocator My application is using that allocator implementation in a std::vector< #define MAX_DIRECTORY_LISTING 512 std::vector< WIN32_FIND_DATA, LocalAllocator< WIN32_FIND_DATA, MAX_DIRECTORY_LISTING > > file_list; WIN32_FIND_DATA find_data = { 0 }; HANDLE find_file = ::FindFirstFile( folder.c_str(), &find_data ); if( NULL != find_file ) { do { // access violation here on the 257th item. file_list.push_back( find_data ); } while ( ::FindNextFile( find_file, &find_data ) ); ::FindClose( find_file ); } // data submitted to the API that requires LocalAlloc()'d array of WIN32_FIND_DATA structures SubmitData( &file_list.front() ); On the 257th item added to the vector<, the application crashes with an access violation: Data Abort: Thread=8e1b0400 Proc=8031c1b0 'rapiclnt' AKY=00008001 PC=03f9e3c8(coredll.dll+0x000543c8) RA=03f9ff04(coredll.dll+0x00055f04) BVA=21ae0020 FSR=00000007 First-chance exception at 0x03f9e3c8 in rapiclnt.exe: 0xC0000005: Access violation reading location 0x01ae0020. LocalAllocator::allocate is called with an n=512 and LocalReAlloc() succeeds. The actual Access Violation exception occurs within the std::vector< code after the LocalAllocator::allocate call: 0x03f9e3c8 0x03f9ff04 > MyLib.dll!stlp_std::priv::__copy_trivial(const void* __first = 0x01ae0020, const void* __last = 0x01b03020, void* __result = 0x01b10020) Line: 224, Byte Offsets: 0x3c C++ MyLib.dll!stlp_std::vector<_WIN32_FIND_DATAW,LocalAllocator<_WIN32_FIND_DATAW,512> >::_M_insert_overflow(_WIN32_FIND_DATAW* __pos = 0x01b03020, _WIN32_FIND_DATAW& __x = {...}, stlp_std::__true_type& __formal = {...}, unsigned int __fill_len = 1, bool __atend = true) Line: 112, Byte Offsets: 0x5c C++ MyLib.dll!stlp_std::vector<_WIN32_FIND_DATAW,LocalAllocator<_WIN32_FIND_DATAW,512> >::push_back(_WIN32_FIND_DATAW& __x = {...}) Line: 388, Byte Offsets: 0xa0 C++ MyLib.dll!Foo(unsigned long int cbInput = 16, unsigned char* pInput = 0x01a45620, unsigned long int* pcbOutput = 0x1dabfbbc, unsigned char** ppOutput = 0x1dabfbc0, IRAPIStream* __formal = 0x00000000) Line: 66, Byte Offsets: 0x1e4 C++ If anybody can point out what I may be doing wrong, I would appreciate it. Thanks, PaulH

    Read the article

  • Argc/Argv C Problems

    - by Salman
    Hey all, If I have the following code: main(int argc, char *argv[]){ char serveradd[20]; strcpy(serveradd, argv[1]); int port = atoi(argv[2]); printf("%s %d \n", serveradd, port); The first two arguments to the command line are printed. However, if I do this: char serveradd[20]; strcpy(serveradd, argv[1]); int port = atoi(argv[2]); char versionnum[1]; strcpy(versionnum, argv[3]); printf("%s %d %s \n", serveradd, port, versionnum);` The first argument (serveradd) does not print out to the screen and is not being stored... Why is this happening and how can I fix it? Thanks!

    Read the article

  • Partial template specialization for more than one typename

    - by Matt Joiner
    In the following code, I want to consider functions (Ops) that have void return to instead be considered to return true. The type Retval, and the return value of Op are always matching. I'm not able to discriminate using the type traits shown here, and attempts to create a partial template specialization based on Retval have failed due the presence of the other template variables, Op and Args. How do I specialize only some variables in a template specialization without getting errors? Is there any other way to alter behaviour based on the return type of Op? template <typename Retval, typename Op, typename... Args> Retval single_op_wrapper( Retval const failval, char const *const opname, Op const op, Cpfs &cpfs, Args... args) { try { CallContext callctx(cpfs, opname); Retval retval; if (std::is_same<bool, Retval>::value) { (callctx.*op)(args...); retval = true; } else { retval = (callctx.*op)(args...); } assert(retval != failval); callctx.commit(cpfs); return retval; } catch (CpfsError const &exc) { cpfs_errno_set(exc.fserrno); LOGF(Info, "Failed with %s", cpfs_errno_str(exc.fserrno)); } return failval; }

    Read the article

  • Intel MKL memory management and exceptions

    - by Andrew
    Hello everyone, I am trying out Intel MKL and it appears that they have their own memory management (C-style). They suggest using their MKL_malloc/MKL_free pairs for vectors and matrices and I do not know what is a good way to handle it. One of the reasons for that is that memory-alignment is recommended to be at least 16-byte and with these routines it is specified explicitly. I used to rely on auto_ptr and boost::smart_ptr a lot to forget about memory clean-ups. How can I write an exception-safe program with MKL memory management or should I just use regular auto_ptr's and not bother? Thanks in advance. EDIT http://software.intel.com/sites/products/documentation/hpc/mkl/win/index.htm this link may explain why I brought up the question UPDATE I used an idea from the answer below for allocator. This is what I have now: template <typename T, size_t TALIGN=16, size_t TBLOCK=4> class aligned_allocator : public std::allocator<T> { public: pointer allocate(size_type n, const void *hint) { pointer p = NULL; size_t count = sizeof(T) * n; size_t count_left = count % TBLOCK; if( count_left != 0 ) count += TBLOCK - count_left; if ( !hint ) p = reinterpret_cast<pointer>(MKL_malloc (count,TALIGN)); else p = reinterpret_cast<pointer>(MKL_realloc((void*)hint,count,TALIGN)); return p; } void deallocate(pointer p, size_type n){ MKL_free(p); } }; If anybody has any suggestions, feel free to make it better.

    Read the article

  • how to cout a vector of structs (that's a class member, using extraction operator)

    - by Julz
    hi, i'm trying to simply cout the elements of a vector using an overloaded extraction operator. the vector contians Point, which is just a struct containing two doubles. the vector is a private member of a class called Polygon, so heres my Point.h #ifndef POINT_H #define POINT_H #include <iostream> #include <string> #include <sstream> struct Point { double x; double y; //constructor Point() { x = 0.0; y = 0.0; } friend std::istream& operator >>(std::istream& stream, Point &p) { stream >> std::ws; stream >> p.x; stream >> p.y; return stream; } friend std::ostream& operator << (std::ostream& stream, Point &p) { stream << p.x << p.y; return stream; } }; #endif my Polygon.h #ifndef POLYGON_H #define POLYGON_H #include "Segment.h" #include <vector> class Polygon { //insertion operator needs work friend std::istream & operator >> (std::istream &inStream, Polygon &vertStr); // extraction operator friend std::ostream & operator << (std::ostream &outStream, const Polygon &vertStr); public: //Constructor Polygon(const std::vector<Point> &theVerts); //Default Constructor Polygon(); //Copy Constructor Polygon(const Polygon &polyCopy); //Accessor/Modifier methods inline std::vector<Point> getVector() const {return vertices;} //Return number of Vector elements inline int sizeOfVect() const {return vertices.size();} //add Point elements to vector inline void setVertices(const Point &theVerts){vertices.push_back (theVerts);} private: std::vector<Point> vertices; }; and Polygon.cc using namespace std; #include "Polygon.h" // Constructor Polygon::Polygon(const vector<Point> &theVerts) { vertices = theVerts; } //Default Constructor Polygon::Polygon(){} istream & operator >> (istream &inStream, Polygon::Polygon &vertStr) { inStream >> ws; inStream >> vertStr; return inStream; } // extraction operator ostream & operator << (ostream &outStream, const Polygon::Polygon &vertStr) { outStream << vertStr.vertices << endl; return outStream; } i figure my Point insertion/extraction is right, i can insert and cout using it and i figure i should be able to just...... cout << myPoly[i] << endl; in my driver? (in a loop) or even... cout << myPoly[0] << endl; without a loop? i've tried all sorts of myPoly.at[i]; myPoly.vertices[i]; etc etc also tried all veriations in my extraction function outStream << vertStr.vertices[i] << endl; within loops, etc etc. when i just create a... vector<Point> myVect; in my driver i can just... cout << myVect.at(i) << endl; no problems. tried to find an answer for days, really lost and not through lack of trying!!! thanks in advance for any help. please excuse my lack of comments and formatting also there's bits and pieces missing but i really just need an answer to this problem thanks again

    Read the article

  • C++: Templates for static functions?

    - by Rosarch
    I have a static Utils class. I want certain methods to be templated, but not the entire class. How do I do this? This fails: #pragma once #include <string> using std::string; class Utils { private: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); public: static void PrintLine(const string& line, int tabLevel = 0); static string getTabs(int tabLevel); template<class InputIterator, class Predicate> static set<char> Utils::findAll_if(InputIterator begin, InputIterator end, Predicate pred); }; Error: utils.h(10): error C2143: syntax error : missing ';' before '<' utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C2238: unexpected token(s) preceding ';' utils.h(10): error C2988: unrecognizable template declaration/definition utils.h(10): error C2059: syntax error : '<' What am I doing wrong? What is the correct syntax for this? Incidentally, I'd like to templatize the return value, too. So instead of: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); I'd have: template<class return_t, class InputIterator, class Predicate> static return_t findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); How would I specify that: 1) return_t must be a set of some sort 2) InputIterator must be an iterator 3) InputIterator's type must work with return_t's type. Thanks.

    Read the article

  • What's pcap_pkthdr there for?

    - by httpinterpret
    Code snippet from here: void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data) { .... /* retireve the position of the ip header */ ih = (ip_header *) (pkt_data + 14); //length of ethernet header .... What's const struct pcap_pkthdr *header for, when do we need it, how is it populated (since there is no such info in the packet itself as below)?

    Read the article

< Previous Page | 93 94 95 96 97 98 99 100 101 102 103 104  | Next Page >