Hi, right now i am implementing a Zig-Zag scan in C++. In addition to that i use the libJpeg8a. I want to intervene into the process when encoding images. My questions is: How can i connect to the scanning process out of C++??? Or: And where exactly is the zig zag scan located within the libJpeg??? ...
I have a class that is derived from ostream: class my_ostream: public std::ostream { // ... } I want to make a manipulator (for example do_something), that works specifically to this class, like this: my_ostream s; s << "some text" << do_something << "some more text"; I did the following: std::ostream &do_something(std::ostrea...
Title probably doesn't make a lot of sense, so I'll start with some code: class Foo : public std::vector<Foo> { }; ... Foo f; f.push_back( Foo() ); Why is this allowed by the compiler? My brain is melting at this stage, so can anyone explain whether there are any reasons you would want to do this? Unfortunately I've just seen a sim...
I have some trouble understanding the need for std::result_of in C++0x. If I understood correctly, result_of is used to obtain the resulting type of invoking a function object with certain types of parameters. For example: template <typename F, typename Arg> typename std::result_of<F(Arg)>::type invoke(F f, Arg a) { return f(a); } ...
Dear all I want to know why cant we create object if the constructor is in private section. I know that if i make a method static i can call that method using <classname> :: <methodname(...)>; But why can't we create object is what I don't understand. I also know if my method is not static then also I can call functio...
I'm looking for some STL, boost, or similar container to use the same way indexes are used in databases to search for record using a query like this: select * from table1 where field1 starting with 'X'; or select * from table1 where field1 like 'X%'; I thought about using std::map, but I cannot because I need to search for fields t...
I want to create a simple chat application that supports voice and video (something like Skype or Google Talk). I don't want to write everything from scratch, so my question is do you know some good libraries for that? I stumbled over libjingle (c++) and Smash (Java), both implementing the XMPP extension Jingle. Would you recommend one...
Hey, I'm experiencing some problems with breaking my code to reusable parts using templates and inheritance. I'd like to achieve that my tree class and avltree class use the same node class and that avltree class inherits some methods from the tree class and adds some specific ones. So I came up with the code below. Compiler throws an e...
I have a large number of sets of integers, which I have, in turn, put into a vector of pointers. I need to be able to update these sets of integers in parallel without causing a race condition. More specifically. I am using OpenMP's "parallel for" construct. For dealing with shared resources, OpenMP offers a handy "atomic directive," w...
I am using the C++ interface to Prolog (the classes and methods of SWI-cpp.h). For working out a simple backtracking that john likes mary and emma and sara: likes(john, mary). likes(john, emma). likes(john, ashley). I can just do: { PlFrame fr; PlTermv av(2); av[0] = PlCompound("john"); PlQuery q("likes", av); while (q.nex...
Hello, I stumble upon a problem, and can't find a solution. So what I want to do is uncompress data in qt, using qUncompress(QByteArray), send from www in gzip format. I used wireshark to determine that this is valid gzip stream, also tested with zip/rar and both can uncompress it. Code so far, is like this: static const char dat...
Hey all, I'm building OpenCV2.1 from top of branch in 64 bit mode, when I link the libraries against my code (that works in 32 bit mode on XP), I get the dialog: "The application was unable to start correctly (0xc0150002) Click OK to close the application" When I start the application. The event viewer is pointing at one of the OpenC...
Hello All, I have the following piece of snippet Class Sample { Obj_Class1 o1; Obj_Class2 o2;}; But the size of Obj_Class1 and Obj_Class2 is huge so that the compiler shows a warning "Consider moving some space to heap". I was asked to replace Obj_Class1 o1 with Obj_Class1* o1 = new Obj_Class1(); But I feel that there is no use of ...
how can i transform a method (that performs a+b and returns the result) from add(a,b) to a.add(b)? i read this somewhere and i can't remember what is the technique called... does it depends on the language? is this possible in javascript? ...
Hi, I have 3 function in my class B. These three function have to access member function of other class A. I did this by creating object of class A in class B constructor and tried to access that object in functions of class B. But its showing error. How can i assess the same object in these three functions. Where i have to create obj...
I am using gcc. I am aware how the virtual destructors solve the problem when we destroy a derived class object pointed by a base class pointer. I want to know how do they work? class A { public: A(){cout<<"A constructor"<<endl;} ~A(){cout<<"A destructor"<<endl;} }; class B:public A { public: B(){cout<<"B ...
Hey everybody, I need a bit of a hand with declaring a string array in my class header file in C++. atm it looks like this: //Maze.h #include <string> class Maze { GLfloat mazeSize, mazeX, mazeY, mazeZ; string* mazeLayout; public: Maze ( ); void render(); }; and the constructor looks like this: //Maze.cpp #include...
Hi, Recently I found a C library that I want to use in my C++ project. This code is configured with global variables and writes it's output to memory pointed by static pointers. When I execute my project I would like 2 instances of the C program to run: one with configuration A and one with configuration B. I can't afford to run my prog...
Why does the following not invoke the overloaded operator== (const String &, const String &)? "cobble" == "stone" ...
I'm building a small BigInt library in C++ for use in my programming language. The structure is like the following: short digits[ 1000 ]; int len; I have a function that converts a string into a bigint by splitting it up into single chars and putting them into digits. The numbers in digits are all reversed, so the number 123 woul...