Code snippet (normal pointer) int *pi = new int; int i = 90; pi = &i; int k = *pi + 10; cout<<k<<endl; delete pi; [Output: 100] Code snippet (auto pointer) Case 1: std::auto_ptr<int> pi(new int); int i = 90; pi = &i; int k = *pi + 10; //Throws unhandled exception error at this point while debugging. cout<<k<<endl; //delete pi; (It...
I have these two functions (with Point2D & LineVector (has 2 Point2D member variables) classes and SQUARE macro predefined) inline float distance(const Point2D &p1,const Point2D &p2) { return sqrt(SQUARE(p2.getX()-p1.getX())+SQUARE(p2.getY()-p1.getY())); } inline float maxDistance(const LineVector &lv1,const LineVector &lv2) { ...
Hi, compare vector with other kind of container in stl? Thanks, Arul ...
Due to specific requirements [*], I need a singly-linked list implementation that uses integer indices instead of pointers to link nodes. The indices are always interpreted with respect to a vector containing the list nodes. I thought I might achieve this by defining my own allocator, but looking into the gcc's implementation of , they...
Consider this program: #include <map> #include <vector> typedef std::vector<int> IntVector; typedef std::map<IntVector,double> Map; void foo(Map& m,const IntVector& v) { Map::iterator i = m.find(v); i->first.push_back(10); }; int main() { Map m; IntVector v(10,10); foo(m,v); return 0; } Using g++ 4.4.0, I get his com...
Hi, I have non-template class with a templatized constructor. This code compiles for me. But i remember that somewhere i have referred that constructors cannot be templates. Can someone explain whether this is a valid usage? typedef double Vector; //enum Method {A, B, C, D, E, F}; struct A {}; class Butcher { public: template <cla...
I was perusing section 13.5 after refuting the notion that built-in operators do not participate in overload resolution, and noticed that there is no section on operator->*. It is just a generic binary operator. Its brethren, operator->, operator*, and operator[], are all required to be non-static member functions. This precludes defini...
I am using mmap call to read from a very big file using simple pointer arithmetic in C++. The problem is that when I read small chunks of data (in the order of KBs) multiple times, each read take the same amount of time as the previous one. How can I know if the disk is being accessed to fulfill my request or whether the request is being...
Hi! I want to create a small code in C++ with the same functionality as "tail-f": watch for new lines in a text file and show them in the standard output. The idea is to have a thread that monitors the file Is there an easy way to do it without opening and closing the file each time? ...
"Introduction" I'm relatively new to C++. I went through all the basic stuff and managed to build 2-3 simple interpreters for my programming languages. The first thing that gave and still gives me a headache: Implementing the type system of my language in C++ Think of that: Ruby, Python, PHP and Co. have a lot of built-in types which ...
I'm currently trying to optimize the sluggish process of retrieving a page of log entries from the SQLite database. I noticed I almost always retrieve next entries along with count of available entries: SELECT time, level, type, text FROM Logs WHERE level IN (%s) ORDER BY time DESC, id DESC LIMIT LOG_...
I am not sure how to approach this problem: 'Player' class mantains a list of Bullet* objects: class Player { protected: std::list< Bullet* > m_pBullet_list; } When the player fires a Bullet, it is added to this list. Also, inside the constructor of bullet, a reference of the same object is updated in CollisionMgr, where Collisio...
I know that CppUnit will handle the exceptions through: CPPUNIT_ASSERT_THROW(expression,ExceptionType); Can anybody explain theoretically how CppUnit will handle the exception? ...
I have images which have line segments, rays etc. I am representing these line segments using Bresenham algorithm (means whatever coordinates I get using this algorithm between two points). Now I want to do operations such as finding intersection point between two line segments, finding the projection of one vector onto other etc... The...
Hi All, I am trying to run a console C++ application linking with my DLL files from the command prompt in a XP windows machine. Recently I have started getting "This program cannot be run in DOS mode." as an error message. As I understand this is a filler message in all DLL's to print if this exe was invoked in a pure MS-DOS environment...
Hi All, I am using WMI to get SMBIOS data and for that I am using following code to initialize the IWbemLocator interface through a call to CoCreateInstance. CoCreateInstance(CLSID_WbemLocator, 0, CLSCTX_INPROC_SERVER, IID_IWebLocator, (LPVOID *) &pLoc); But it always returns FAILURE. I think its due to some environment issue but w...
typedef boost::interprocess::managed_shared_memory::segment_manager segment_manager_t; // Works fine, segment_manager is a class typedef boost::interprocess::adaptive_pool allocator_t; // Can't do this, adaptive_pool is a template The idea is that if I want to switch between boost interprocess' several different options for sh...
Hello I'm doing batch-testing on our win32 c++ programs. Some of them crash. What's the best way to catch those crash from the command line and report it? thanks edit: answer: 1) you can't catch another process's exception from batch / command line 2) example to do it right in c#: http://stackoverflow.com/questions/673036/how-to-ha...
I am using boost::interprocess::message_queue, with VC++ (in Microsoft Visual Studio 2005). It is working properly in Debug mode. Then when I compile my program in Release mode it stops working, every time I call "try_send" it returns false. I don't understand what could be the settings that are different between Release and Debug mode, ...
I'm making an injected .dll written in C++, and I want to communicate with a C# app using named pipes. Now, I am using the built in System.IO.Pipe .net classes in the C# app, and I'm using the regular functions in C++. I don't have much experience in C++ (Read: This is my first C++ code..), tho I'm experienced in C#. It seems that the...