class a { virtual void foo(void) ; }; class b : public a { public: virtual void foo(void) { cout<< "class b"; } }; int main ( ) { class a *b_ptr = new b ; b_ptr->foo(); } please guide me why the b_ptr->foo() will not call the foo() function of the class b? ...
I tried searching documentation but couldn't find an equivalent of keyset function for maps in C++ stl. Is it C++ really that poor. ...
Hi I have a question about debugging a running C++ program in Linux. If a programming is already running and can't be interrupted, how to do that. I can find three ways, but I don't know too much about details, I am grateful if any one can elaborate it deeper. 1) we can use GDB by specifying the process ID gdb -p PID In this case...
I currently have a machine with an Opteron 275 (2.2Ghz), which is a dual core CPU, and 4GB of RAM, along with a very fast hard drive. I find that when compiling even somewhat simple projects that use C++ templates (think boost, etc.), my compile times can take quite a while (minutes for small things, much longer for bigger projects). Unf...
What is the most memory efficient way to remove duplicate lines in a large text file using C++? Let me clarify, I'm not asking for code, just the best method. The duplicate lines are not guaranteed to be adjacent. I realize that an approach optimized for minimal memory usage would result in slower speeds however this is my restriction...
Hi all, I need an array to hold member-function-pointers of different classes. How can I define the array? The code should look like this : arr[0] = &CMyClass::FuncX; arr[1] = &CYourClass::FuncY; arr[2] = &CHerClass::FuncZ; I tried void*, but it doesn't work. Thanks. Best regards, Zach@Shine ...
Previously, I am using STL map to perform the mentioned task. struct ltstr { bool operator()(std::string s1, std::string s2) const { const int l1 = s1.length(); const int l2 = s2.length(); if (l1 == l2) { // In alphabetical order. return s1.compare(s2) < 0; } // From longest leng...
Hello all, First to give you some background: I have some research code which performs a Monte Carlo simulation, essential what happens is I iterate through a collection of objects, compute a number of vectors from their surface then for each vector I iterate through the collection of objects again to see if the vector hits another obje...
This might be a repeat, but my google-fu failed to find it. I want to print numbers to a file using the stl with the number of decimal places, rather than overall precision. So, if I do this: int precision = 16; std::vector<double> thePoint(3); thePoint[0] = 86.3671436; thePoint[0] = -334.8866574; thePoint[0] = 24.2814; ofstream file...
Is TeeChart .NET built from the same source as TeeChart VCL? I'm just wandering as we have a VCL application heavily dependent on TeeChart and I would like to redevelop the GUI component in .NET so I can switch from the Codegear IDE to Visual Studio. ...
Hi, I have a vector of Rect: vector<Rect> myRecVec; I would like to remove the ones which are overlapping in the vector: So I have 2 nested loop like this: vector<Rect>::iterator iter1 = myRecVec.begin(); vector<Rect>::iterator iter2 = myRecVec.begin(); while( iter1 != myRecVec.end() ) { Rectangle r1 = *iter1; while( iter2 ...
Just come up with this question. Any hint? ...
Can C/C++ be choice of keeping all your logic (business/domain) for web application? Why? I've two resources (cousins) having knowledge on C/C++ and me also good in C/C++, Python, HTML, CSS and JavaScript. We like to utilize our free time to work on our some good ideas we developed together. The ideas require knowledge of web applica...
I am trying to make the raycast give me the distance of the terrain and nothing else. But I'm not sure how to use the group Mask Filter. virtual NxShape* raycastClosestShape ( const NxRay& worldRay, NxShapesType shapeType, NxRaycastHit& hit, NxU32 groups=0xffffffff, NxReal maxDist=NX_MAX_F32, NxU32 hintFlags=0xffffffff...
I am playing with C++ and pthreads and so far so good. I can access a class member function if it's static and I've read that I can access a normal class member functions if I pass "this" as an argument with pthread_create, because c++ does this to, under the hood. But my problem is that I want to give an int to that function, and I don'...
void foo() { struct Foo { .. }; std::vector<Foo> vec; // why is this illegal? } I'm not returning Foo to the outside world. It's just a temporary type that I use within the function. ...
The size of a class with no data members is returned as 1 byte, even though there is an implicit 'this' pointer declared. Shouldn't the size returned be 4 bytes(on a 32 bit machine)? I came across articles which indicated that 'this' pointer is not counted for calculating the size of the object. But I am unable to understand the reason f...
On certain error cases ATL invokes AtlThrow() which is implemented as ATL::AtlThrowImpl() which in turn throws CAtlException. The latter is not very good - CAtlException is not even derived from std::exception and also we use our own exceptions hierarchy and now we will have to catch CAtlException separately here and there which is lots ...
I trying to allocate memory for 10 bytes BYTE* tmp; tmp = new BYTE[10]; //or tmp = (BYTE*)malloc(10*sizeof(BYTE)); But after new or malloc operation length of *tmp more than 10 (i.e. '\0' char not in 10 position in tmp array) Why? ...
Every now and then I need to call new[] for built-in types (usually char). The result is an array with uninitialized values and I have to use memset() or std::fill() to initialize the elements. How do I make new[] default-initialize the elements? ...