c++

how to solve the errors of this program

#include <iostream> using std::cout; using std::cin; using std::endl; #include <cstring> void initialize(char[],int*); void input(const char[] ,int&); void print ( const char*,const int); void growOlder (const char [], int* ); bool comparePeople(const char* ,const int*,const char*,const int*); int main(){ char name1[25]; ...

Receiving data from a USB device in C or C++

It starts to bore me that I always have to ask questions about trifles. I simply need a list of all plugged in USB devices and have the user select one to let the console application receive any data the USB device sends. I can then start playing around with the data in my program. I don't want to use library's, only standard C++ func...

boost::function & boost::lambda - call site invocation & accessing _1 and _2 as the type

Sorry for the confusing title. Let me explain via code: #include <string> #include <boost\function.hpp> #include <boost\lambda\lambda.hpp> #include <iostream> int main() { using namespace boost::lambda; boost::function<std::string(std::string, std::string)> f = _1.append(_2); std::string s = f("Hello", "There"); ...

Does the following indicate a bad design?

Hello, I was wondering whether you think the following code usually indicates a bad design ... class X { public: ... private: Y y; }; Class Y { public: Y( X& value ){ x = value; }; private: X& x; } (i.e. there is some sort of cyclic dependency between the classes X and Y). ...

How to draw to screen in c++ ?

How would I draw something on the screen ? not the console window but the entire screen, preferably with the console minimised. Also, would it show up on a printscreen ? What I want to do is create something like a layer on top of the screen that only me and my aplication are aware of yet still be able to use aplications as usual. Here...

Boost::Thread linking error on OSX?

So I'm going nuts trying to figure this one out. Here's my basic setup: I'm compiling a shared library with a bunch of core functionality that uses a lot of boost stuff. We'll call this library libpf_core.so. It's linked with the boost static libraries, specifically the python, system, filesystem, thread, and program_options librarie...

boost::function & boost::lambda again

Follow-up to post: http://stackoverflow.com/questions/2978096/using-width-precision-specifiers-with-boostformat I'm trying to use boost::function to create a function that uses lambdas to format a string with boost::format. Ultimately what I'm trying to achieve is using width & precision specifiers for strings with format. boost::forma...

Algorithm to match list of regular expressions

I have two algorithmic questions for a project I am working on. I have thought about these, and have some suspicions, but I would love to hear the community's input as well. Suppose I have a string, and a list of N regular expressions (actually they are wildcard patterns representing a subset of full regex functionality). I want to k...

Strict pointer aliasing: is access through a 'volatile' pointer/reference a solution?

On the heels of a specific problem, a self-answer and comments to it, I'd like to understand if it is a proper solution, workaround/hack or just plain wrong. Specifically, I rewrote code: T x = ...; if (*reinterpret_cast <int*> (&x) == 0) ... As: T x = ...; if (*reinterpret_cast <volatile int*> (&x) == 0) ... with a volatile q...

How can I use cout<<myclass?

myclass is a c++ class writed by me . and when I write myclass x; cout << x; // how to output is " 10 " or "20" like intger or float value ...

C++ switch table performance

Does the time taken by a switch statement (or jump table in compiled form) to "decide" where to jump rise by the number of casees it contains? ...

Drawing N-width lines?

Given a series of points, how could I calculate the vector for that line 5 pixels away? Ex: Given: \ \ \ How could I find the vector for \ \ \ \ \ \ The ones on the right. I'm trying to figure out how programs like Flash can make thick outlines. Thanks ...

How do I get the size of the boost buffer

I am trying to make an asynchronised server in visual studio and I use boost::asio::async_read(m_socket, boost::asio::buffer(m_buffer), boost::bind(&tcp_connection::handle_read, shared_from_this(), boost::asio::placeholders::error)); to get the buffer to be put in m_buffer ...

Storing UTF-8 XML using Word's CustomXMLPart or any other supported way

I am writing a Word add-in which is supposed to store some own XML data per document using Word object model and its CustomXMLPart. The problem I am now facing is the lack of IStream-like functionality for reading/writing XML to/from a CustomXMLPart. It only provides BSTR interface and I am puzzled how to handle UTF-8 XMLs with BSTRs. To...

c++ function overloading, making fwrite/fread act like PHP versions

I'm used to the PHP fwrite/fread parameter orders, and i want to make them the same in C++ too. I want it to work with char and string types, and also any data type i put in it (only if length is defined). I am total noob on c++, this is what i made so far: Edit: fixed the std::string &buf size_t fwrite(FILE *fp, const std::string &bu...

Integration (math) in C++

Hi all, I'm looking for a library to find the integral of a given set of random data (rather than a function) in C++ (or C, but preferably C++). There is another question asking about integration in C but the answers discuss more how to integrate a function (I think...). I understand that this can be done simply by calculating the ar...

Access element of pointed std::vector

I have a function where I provide a pointer to a std::vector. I want to make x = to vector[element] but i'm getting compiler errors. I'm doing: void Function(std::vector<int> *input) { int a; a = *input[0]; } What is the right way to do this? Thanks ...

How to operate different class just one functionsone

class A {}; class B {}; class C {}; class D {}; //A+B , A+C, B+C , A+D, D+C namely all of these combinations will be possible just one functions ...

Quantifying the Performance of Garbage Collection vs. Explicit Memory Management

I found this article here: Quantifying the Performance of Garbage Collection vs. Explicit Memory Management http://www.cs.umass.edu/~emery/pubs/gcvsmalloc.pdf In the conclusion section, it reads: Comparing runtime, space consumption, and virtual memory footprints over a range of benchmarks, we show that the runtime performan...

rand () for c++ with variables...

int userHP = 100; int enemyHP = rand() % ((userHP - 50) - (userHP - 75)) + 1; okay, for some reason this doesnt seem to work right, im trying to get 50 -25 hp for enemys. also id rather it be a percentage... like int enemyHP = rand() % ((userHP / 50%) - (userHP / 75%)) + 1; but id like to stick with integers and not mess with flo...