c++

What is the copy constructor bug causing parsing errors?

I'm writing a compiler for a small language, and my Parser class is currently in charge of building an AST for use later. However, recursive expressions are not working correctly because the vector in each AST node that holds child nodes are not working correctly. Currently my AST's header file looks like this: class AST { public: e...

Member value changes between successive calls of the same function

Hi all! I have a CognitiveEntity class, defined this way: class CognitiveEntity : public Object { public: CognitiveEntity (FuzzyCognitiveMap fcm, SystemState s); ~CognitiveEntity (); template <typename T> void RegisterChange (std::string context, T value); bool operator!= (const CognitiveEntity& rhs) const; private: FuzzyC...

Multi-statement Macros in C++

In C++, is it possible to make a multi-statement macro with nested if statements inside of it like the one below? I've been attempting it for a while now and I'm getting a scope issue for the second if statement not being able to see 'symbol'. Maybe I need to understand macros further. #define MATCH_SYMBOL( symbol, token) if(someth...

C++ pass pointer by reference and assign default value

hi! I would like to pass a pointer by reference to a function, such that i can actually change the address the passed pointer is pointing to and i'd like to assign this argument a default value. something like this: in the declaration void myFunc(SomeType* &var=NULL); and the definition: void MyClass::myFunc(SomeType* &var){ i...

How to call erase with a reverse iterator

I am trying to do something like this: for ( std::list< Cursor::Enum >::reverse_iterator i = m_CursorStack.rbegin(); i != m_CursorStack.rend(); ++i ) { if ( *i == pCursor ) { m_CursorStack.erase( i ); break; } } However erase takes an iterator and not a reverse iterator. is there a way to convert a reverse ...

How do I free SQLServerCE's COM instance from the current running process?

It's been a while since I touched COM so be nice ;) This is under WindowsCE 5.0 with SQLServerCE 2.0. After calling this to load SQLServerCE 2.0 : - IDBInitialize *pIDBInitialize = NULL; CoCreateInstance(CLSID_SQLSERVERCE_2_0, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize, (void**)&pIDBInitialize); Module load occurs for SSCE20.dll w...

How can I interface with a third party module that only provides JTAPI API From C++?

I'm supporting a large system written in C++ and we now have a requirement for our application to talk with a third party system which only provides a JTAPI interface. It would appear that I am stuck writing a JTAPI proxy in Java that talks JTAPI on one side and some more language-neutral API on the other. However, this feels like it sho...

How to draw the graph in framebuffer using c language..?

Hi friends, i am new to this linux framebuffer so do anybody guide me to draw the line-graph in framebuffer. And i have the code to draw graph in turbo c but now in linux. So please help me out. Thank You, Rahul ...

Finding definitions/references to C++ class members in Vim

I'm using Vim for a C++ project that I've started working on and I've been spending a lot of time lately browsing through the existing code to get a hang of it. To make the browsing easier, I've setup ctags and cscope in Vim to jump to definitions and find references. However, I find that neither of them are intelligent enough to know w...

Bignum implementation that has efficient addition of small integers

I have been using python's native bignums for an algorithm and decided to try and speed it up by converting it to C++. When I used long longs, the C++ was about 100x faster than the python, but when I used GMP bindings in C++, it was only 10x faster than the python (for the same cases that fit in long longs). Is there a better bignum im...

Static variable initialization?

I want to know why exactly static variables in C, C++ and Java are initialized by zero by default? And why this is not true for local variables? ...

Is this undefined?

Well, I'm not really in serious need of this answer, I am just inquisitive. Expressions like *ptr++ = a are perfectly valid since we are operating on two objects ptr and *ptr but if i write *ptr++ = *ptr + a is it still valid ? For example consider the following snippet: int main(void){ int a[] = {5,7,8,9,2}; int* p =a; *p+...

Writing binary files using C++: does the default locale matter?

I have code that manipulates binary files using fstream with the binary flag set and using the unformatted I/O functions read and write. This works correctly on all systems I've ever used (the bits in the file are exactly as expected), but those are basically all U.S. English. I have been wondering about the potential for these bytes to ...

UMFPACK, using with Microsoft Visual Studio 2008 ( C++ )

Hi I've seen this topic about UMFPack and its usage. http://stackoverflow.com/questions/1242190/c-memory-efficient-solution-for-axb-linear-algebra-system But I couldn't implement it in Visual Studio 2008! I want to use C++ and UMFPACK to solve a triplet mode (Sparse Matrix) and nothing else! I dont wnat any report or something, I just...

Is C++ code generation in ANTLR 3.2 ready?

Hi, I was trying hard to make ANTLR 3.2 generate parser/lexer in C++. It was fruitless. Things went well with Java & C though. I was using this tutorial to get started: http://www.ibm.com/developerworks/aix/library/au-c%5Fplusplus%5Fantlr/index.html When I checked the *.stg files, I found that: CPP has only ./tool/src/main/resources/...

vptr - virtual tables

hey, there is something i still don't get. for every class i declare there is a hidden vptr member pointing to the class virtual table. let's say i have this declaration : class BASE { virtual_table* vptr; //that's hidden of course , just stating the obvious virtual void foo(); } class DERIVED : public BASE { virtual_tabl...

c++ error - help needed

Thanks eveyerone for giveing me some idea's to try and I'll try them. The code it runs now. **** IT RUNS LIKE THIS Input room dimensions Length? ( I enter 12 ) Width? ( I enter 10) Height? ( I enter 8) MY Answer = You will need the following amount of paint in gallons: 3 Press any key to continue …. But I need it to say ( You ...

C++ beginner question on Tuple-at-a-time join implementation

Hi All,I am just browsing through this very old webpage, http://www.cs.cornell.edu/Info/Courses/Fall-97/CS432/proj3/index.html and find this project interesting,since I just started learning C++,I really like to try doing the simplest "Tuple-At-A-Time" join as mentioned on the page using C++. I know how Tuple-at-a-time works,but had a...

"Error in the program" Can anybody clear this error..? (LINUX FRAMEBUFFER PROGRAM)

#include <unistd.h> #include <stdio.h> #include <fcntl.h> #include <linux/fb.h> #include <sys/mman.h> int main() { int fbfd = 0; struct fb_var_screeninfo vinfo; struct fb_fix_screeninfo finfo; long int screensize = 0; char fbp = 0; int x = 0, y = 0; long int location = 0; // Open the file for reading and writing fbfd = open("/dev/fb0",...

C++: Safe way to cast an integer to a pointer

I need to convert an integral type which contains an address to the actual pointer type. I could use reinterpret_cast as follows: MyClass *mc1 = reinterpret_cast<MyClass*>(the_integer); However, this does not perform any run-time checks to see if the address in question actually holds a MyClass object. I want to know if there is any b...