Search Results

Search found 7500 results on 300 pages for 'const char'.

Page 215/300 | < Previous Page | 211 212 213 214 215 216 217 218 219 220 221 222  | Next Page >

• How do I make a class whose interface matches double, but upon which templates can be specialized?

  - by Neil G

  How do I make a class whose interface matches double, but whose templated types do not dynamic cast to double? The reason is that I have a run-time type system, and I want to be able to have a type that works just like double: template<int min_value, int max_value> class BoundedDouble: public double {}; And then inherit use template specialization to get run-time information about that type: template<typename T> class Type { etc. } template<int min_value, int max_value> class Type<BoundedDouble<min_value, max_value>> { int min() const { return min_value; } etc. } But, you can't inherit from double...

  Read the article

• INET_ATON() and INET_NTOA() in PHP?

  - by blerh

  I want to store IP addresses in my database, but I also need to use them throughout my application. I read about using INET_ATON() and INET_NTOA() in my MySQL queries to get a 32-bit unsigned integer out of an IP address, which is exactly what I want as it will make searching through the database faster than using char(15). The thing is, I can't find a function that does the same sort of thing in PHP. The only thing I came across is: http://php.net/manual/en/function.ip2long.php So I tested it: $ip = $_SERVER['REMOTE_ADDR']; echo ip2long($ip); And it outputs nothing. In the example they gave it seems to work, but then again I'm not exactly sure if ip2long() does the same thing as INET_ATON(). Does someone know a PHP function that will do this? Or even a completely new solution to storing an IP address in a database? Thanks.

  Read the article

• iPhone OpenGL Template is cheating?

  - by carrots

  XCode's OpenGL template seems to be cheating to solve this "stretched" viewport problem I've been trying to understand for the last 3 hours. In the iphone "OpenGL ES Application" template, the colorful square that bounces up and down on the screen is not really a square at all! ES1Renderer.m (the ES2 file as well) static const GLfloat squareVertices[] = { -0.5f, -0.33f, 0.5f, -0.33f, -0.5f, 0.33f, 0.5f, 0.33f, }; But it comes out looking square on the device/simulator due to the stretching/squashing effect of a non-square viewport. I tried to fix it by fiddling with glFrustumf() but that doesn't seem to change the aspect ratio. I was able to get things looking good (not-stretched) when I fed glViewport() with a 1:1 widht:height.. But this doesn't seem like the answer because it offsets the viewport placement. What's the right way to correct for this stretching and why doesn't XCode do it that way?

  Read the article

• Determine if a string contains only alphanumeric characters (or a space)

  - by dreamlax

  I'm learning C++ and I am writing a function that determines whether a string contains only alphanumeric characters and spaces. I suppose I am effectively testing whether it matches the regular expression ^[[:alnum:] ]+$ but without using regular expressions. I have seen a lot of algorithms revolve around iterators, so I tried to find a solution that made use of iterators, and this is what I have: #include <algorithm> static inline bool is_not_alnum_space(char c) { return !(isalpha(c) || isdigit(c) || (c == ' ')); } bool string_is_valid(const std::string &str) { return find_if(str.begin(), str.end(), is_not_alnum_space) == str.end(); } Is there a better solution, or a “more C++” way to do this?

  Read the article

• Implementing implicitly shared classes outside of Qt

  - by Timothy Baldridge

  I'm familiar with the way Qt uses D-pointers for managing data. How do I do this in my code? I tried this method: 1) move all data into a struct 2) add a QAtomicInt to the struct 3) implement a = operator and change my constructor/deconstructor to check-up on the reference count. The issue is, when I go to do a shallow copy of the object, I get an error about QObject declaring = as private. How then do I accomplish this? Here's an example of my copy operator: HttpRequest & HttpRequest::operator=(const HttpRequest &other) { other.d->ref.ref(); if (!d->ref.deref()) delete d; d = other.d; return *this; } Am I going about this the wrong way?

  Read the article

• printing menu in terminal and choosing an option, how to?

  - by carlos

  I'm a haskell beginner. I'm trying to make a program that shows a menu through terminal and ask user to introduce an option. Here is the code: main :: IO () main = do putStrLn "0 <- quit" putStrLn "1 <- Hello" putStr "Choose an option: " c <- getChar case c of '0' -> return () '1' -> putChar '\n' >> putStrLn "Hello World" >> main When I use this module in the ghci interpreter everything works like it's suposed to do. But if i compile this with: ghc hello.hs and run it in the terminal, it doesn't display the line "Choose an option:" before ask for a char to be introduced. I think this may be caused because of haskell lazy nature and I don't know how to fix it. Any ideas?

  Read the article

• Why my print current date time (C language) gives different answer

  - by vodkhang

  I want to get the current date (day, mon and year). I found out there are some functions in C to do that like ctime (get the string of time), localtime and gmtime. I tried with following code but the output are different. I get this output: The date and time is Tue Apr 20 2010 (which is correct) The year is : 110 The year is : 110. Does anybody know why? int main(int argc, char** argv) { time_t now; if((now = time(NULL)) == (time_t)-1) { puts("Failure in getting time"); } else { printf("The date and time is: %s\n", ctime(&now)); printf("The year is: %ld\n", localtime(&now)->tm_year); printf("The year is: %ld\n", gmtime(&now)->tm_year); } getchar(); }

  Read the article

• How do I simplify this templated vector initializer loop using lambdas or some kind of STL transform

  - by Neil G

  How do I simplify this templated vector initializer loop using lambdas or some kind of STL transform? template<typename T> template<typename... Args> DotProduct<T>::DotProduct(int n, RNG& rng, Args const&... args) { myBasis.resize(n); for (auto it = myBasis.begin(); it != myBasis.end(); ++it) { typename T::CPDDist cpd(rng, args...); *it = T(cpd); } }

  Read the article

• How to free an Oracle Object-Type passed to an external procedure

  - by chila

  I'm using OTT to pass and load an Object Type from a C++ external procedure. The problem I have is that I don't know how to somehow mark the object for deallocation once extproc has done marshalling it. The object remains in extproc's memory forever making it grow in memory consumtion. Here's part of the code: void decodeFromBuffer(OCIExtProcContext *ctx, GPRS_GPRSCHARGINGRECORD *record, GPRS_GPRSCHARGINGRECORD_ind *recordInd, const unsigned char *buffer, int buffLen, OCIInd *bufferInd) { . . . assert(OCIExtProcGetEnv(ctx, &envh, &svch, &errh) == OCI_SUCCESS); recordInd->_atomic = OCI_IND_NOTNULL; // somehow I should mark the object for deallocation after extproc has done marshalling it // using OCINumberFromInt and OCIStringAssignText to load the object (this memory is never deallocated) . . . } How could I mark the object (and subobjects) for deallocation?

  Read the article

• Does C# compile code inside an if(false) block?

  - by aximili

  I am just wondering if these code blocks gets compiled into .dll I don't think this one gets compiled at all #if SOMETHING_UNDEFINED // some code - this is ignored by the compiler #endif Now what about these? 1. if(false) { // some code - is this compiled? } 2. const bool F = false; if(F) { // some code - is this compiled? } 3. bool F = false; if(F) { // some code - is this compiled? }

  Read the article

• C++ initializing constants and inheritance

  - by pingvinus

  I want to initialize constant in child-class, instead of base class. And use it to get rid of dynamic memory allocation (I know array sizes already, and there will be a few child-classes with different constants). So I try: class A { public: const int x; A() : x(0) {} A(int x) : x(x) {} void f() { double y[this->x]; } }; class B : A { B() : A(2) {} }; Pretty simple, but compiler says: error C2057: expected constant expression How can I say to compiler, that it is really a constant?

  Read the article

• Operator Overloading in C++ as int + obj

  - by Azher

  Hi Guys, I have following class:- class myclass { size_t st; myclass(size_t pst) { st=pst; } operator int() { return (int)st; } int operator+(int intojb) { return int(st) + intobj; } }; this works fine as long as I use it like this:- char* src="This is test string"; int i= myclass(strlen(src)) + 100; but I am unable to do this:- int i= 100+ myclass(strlen(src)); Any idea, how can I achieve this?? Thanks in advance. Regards,

  Read the article

• MySQL encoding problem

  - by heffaklump

  I use Java and JDBC to save japanese characters and it works perfectly on my local MySQL. But when I tried doing the same thing on my web hotels MySQL i get ????? instead of japanese characters. I have made the exact same tables and use exact same code. The only difference I have found is SHOW VARIABLES LIKE 'CHAR%' character_set_client utf8 character_set_connection utf8 character_set_database latin1 character_set_filesystem binary character_set_results utf8 character_set_server latin1 character_set_system utf8 character_sets_dir /s/usr-local/share/mysql/charsets/ character_set_datbase is set to latin1. But I can't change it! Any tips?

  Read the article

• Limit scope of #define

  - by Ujjwal Singh

  What is the correct strategy to limit the scope of #define and avoid unwarrented token collisions. In the following configuration: Main.c # include "Utility_1.h" # include "Utility_2.h" VOID Utility() // Was written without knowing of: Utility_1 & Utility_2 { const UINT ZERO = 0; } VOID Main() { ... } // Collision; for Line:5 Compiler does not indicate what replaced Utility_1.h # define ZERO "Zero" # define ONE "One" BOOL Utility_1(); Utility_2.h # define ZERO '0' # define ONE '1' BOOL Utility_2(); Utility_2.c # include "Utility_2.h" BOOL Utility_2() { // Using: ZERO & ONE } //Collision: Character Literal replaced with String {Edit} Note: This is supposed to be a generic quesition so do not limit yourself to enum or other defined types. i.e. What to do when: I MUST USE #define Please comment on my proposed solution below.. _

  Read the article

• buffer overflow with boost::program_options

  - by f4

  Hello, I have a problem using boost:program_options this simple program, copy-pasted from boosts' documentation : #include <boost/program_options.hpp> int main( int argc, char** argv ) { namespace po = boost::program_options; po::options_description desc("Allowed options"); desc.add_options() ("help", "produce help message") ("compression", po::value<int>(), "set compression level") ; return 0; } fails with a buffer overflow. I have activated the "buffer security switch", and when I run it I get an "unknown exception (0xc0000409)" when I step over the line desc.add_options()... I use Visual Studio 2005 and boost 1.43.0. By the way it does run if I deactivate the switch but I don't feel comfortable doing so... unless it's possible to deactivate it locally. So do you have a solution to this problem? EDIT I found the problem I was linking against libboost_program_options-vc80-mt.lib which wasn't the good library.

  Read the article

• Lazy evaluation with ostream C++ operators

  - by SavinG

  I am looking for a portable way to implement lazy evaluation in C++ for logging class. Let's say that I have a simple logging function like void syslog(int priority, const char *format, ...); then in syslog() function we can do: if (priority < current_priority) return; so we never actually call the formatting function (sprintf). On the other hand, if we use logging stream like log << LOG_NOTICE << "test " << 123; all the formating is always executed, which may take a lot of time. Is there any possibility to actually use all the goodies of ostream (like custom << operator for classes, type safety, elegant syntax...) in a way that the formating is executed AFTER the logging level is checked ?

  Read the article

• How to set up a Bitmap with unmanaged data?

  - by Danvil

  I have int width, height; and IntPtr data; which comes from a unmanaged unsigned char* pointer and I would like to create a Bitmap to show the image data in a GUI. Please consider, that width must not be a multiple of 4, i do not have a "stride" and my image data is aligned as BGRA. The following code works: byte[] pixels = new byte[4*width*height]; System.Runtime.InteropServices.Marshal.Copy(data, pixels, 0, pixels.Length); var bmp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb); for(int i=0; i<height; i++) { for(int j=0; j<width; j++) { int p = 4*(width*i + j); bmp.SetPixel(j, i, Color.FromArgb(pixels[p+3], pixels[p+2], pixels[p+1], pixels[p+0])); } } Is there a more direct way to copy the data?

  Read the article

• Treat a void function as a value

  - by Brendan Long

  I'm writing some terrible, terrible code, and I need a way to put a free() in the middle of a statement. The actual code is: int main(){ return printf("%s", isPalindrome(fgets(malloc(1000), 1000, stdin))?"Yes!\n":"No!\n") >= 0; // leak 1000 bytes of memory } I was using alloca(), but I can't be sure that will actually work on my target computer. My problem is that free returns void, so my code has this error message: error: void value not ignored as it ought to be The obvious idea I had was: int myfree(char *p){ free(p); return 0; } Which is nice in that it makes the code even more unreadable, but I'd prefer not to add another function. I also briefly tried treating free() as a function pointer, but I don't know if that would work, and I don't know enough about C to do it properly. Note: I know this is a terrible idea. Don't try this at home kids.

  Read the article

• STL member variable initalization issue with windows API

  - by Django

  I am creating a windows app that uses a vector of stings as a member variable. For some reason, I can compile but when it tries to get at any of the vectors members is crashes. the error is 0xC0000005: Access violation reading location 0xcdcdcdd9. in the member function of the vector class. this is the size() function where it breaks. size_type capacity() const { // return current length of allocated storage return (this->_Myend - this->_Myfirst); } I am using visual studios 2010. thank you Django

  Read the article

• How to print an isosceles triangle

  - by Steve

  Hello, I'm trying to learn programming by myself, I'm working from a book that has the following problem which I can't solve: Allow the user to input two values: a character to be used for printing an isosceles triangle and the size of the peak for the triangle. For example, if the user inputs # for the character and 6 for the peak, you should produce the following display: # ## ### #### ##### ###### ##### #### ### ## # This is the code I've got so far: char character; int peak; InputValues(out character, out peak); for (int row = 1; row < peak * 2; row++) { for (int col = 1; col <= row; col++) { Console.Write(character); } Console.WriteLine(); } Console.Read() // hold console open Thanks in advance.

  Read the article

• Glib hash table replace

  - by Robert

  I'm using GLib Hash Table. I'm trying to get the current value of the key that I found and then increment its value. I'm not quite sure how can I replace the existing value. typedef struct { gchar *key; guint my_int; } my_struct; char *v; v = g_hash_table_lookup(table, my_struct.key); if (v == NULL) g_hash_table_insert(table, g_strdup(my_struct.key), (gpointer)(my_struct.my_int)); else g_hash_table_replace() // here I'd like to do something like current_val+1 Any ideas will be appreciate it.

  Read the article

• Retain cycle on `self` with blocks

  - by Jonathan Sterling

  I'm afraid this question is pretty basic, but I think it's relevant to a lot of Objective-C programmers who are getting into blocks. What I've heard is that since blocks capture local variables referenced within them as const copies, using self within a block can result in a retain cycle, should that block be copied. So, we are supposed to use __block to force the block to deal directly with self instead of having it copied. __block typeof(self) bself = self; [someObject messageWithBlock:^{ [bself doSomething]; }]; instead of just [someObject messageWithBlock:^{ [self doSomething]; }]; What I'd like to know is the following: if this is true, is there a way that I can avoid the ugliness (aside from using GC)?

  Read the article

• How to log C++ exception if running outside debugger, otherwise rethrow

  - by Stefan Monov

  I wanna do something like this: int main() { try { runApp(); } catch(std::exception const& ex) { if(runningInDebugger()) throw; // let the IDE show me what went wrong else displayMsgBox("Something went wrong! " + ex.what()); } } Needs to work at least in VS2008 but the more debuggers it supports, the better. I want it to check for a debugger at runtime. I don't want to do "#ifdef NDEBUG", because I prefer not to do release builds at all (can't be bothered). So what should I use as a "runningInDebugger()" check?

  Read the article

• Operator() as a subscript (C++)

  - by Ivan Gromov

  I use operator() as a subscript operator this way: double CVector::operator() (int i) const { if (i >= 0 && i < this->size) return this->data[i]; else return 0; } double& CVector::operator() (int i) { return (this->data[i]); } It works when I get values, but I get an error when I try to write assign a value using a(i) = 1; UPD: Error text: Unhandled exception at 0x651cf54a (msvcr100d.dll) in CG.exe: 0xC0000005: Access violation reading location 0xccccccc0.

  Read the article

• Template class implicit copy constructor issues

  - by Nate

  Stepping through my program in gdb, line 108 returns right back to the calling function, and doesn't call the copy constructor in class A, like (I thought) it should: template <class S> class A{ //etc... A( const A & old ){ //do stuff... } //etc... }; template <class T> class B{ //etc... A<T> ReturnsAnA(){ A<T> result; // do some stuff with result return result; //line 108 } //etc... }; Any hints? I've banged my head against the wall about this for 4 hours now, and can't seem to come up with what's happening here.

  Read the article

< Previous Page | 211 212 213 214 215 216 217 218 219 220 221 222  | Next Page >