Consider the following code: std::string my_error_string = "Some error message"; // ... throw std::runtime_error(std::string("Error: ") + my_error_string); The string passed to runtime_error is a temporary returned by string's operator+. Suppose this exception is handled something like: catch (const std::runtime_error& e) { st...
How can we find if a character belongs to a particular codepage? or How can we determine whether a charcter fits into currently active IME for an application. ...
I need to create a map, from integers to sets of tuples, the tuples in a single set have the same size. The problem is that the size of a tuple and its parameter types can be determined at runtime, not compile time. I am imagining something like: std::map<int, std::set<boost::tuple> > but not exctly sure how to exactly do this, bossib...
class Base { public: Base(){} Base(int k):a(k) { } int a; }; class X:virtual public Base { public: X():Base(10){} int x; }; class Y:virtual public Base { public: Y():Base(10){} int y; }; class Z:public X,public Y...
Does the default constructor (created by the compiler) initialize built-in-types? ...
I'm writing system-level code for an embedded system without memory protection (on an ARM Cortex-M1, compiling with gcc 4.3) and need to read/write directly to a memory-mapped register. So far, my code looks like this: #define UART0 0x4000C000 #define UART0CTL (UART0 + 0x30) volatile unsigned int *p; p = UART0CTL; *p &= ~1; Is t...
I wrote several simulation programs in C++ and want to connect their outputs/inputs with pipes (best solution would probably be to use the C++ streams). For this I would like to serialize some objects (for example the simulations output/input are tensors and matrices). How should I handle this problem? I searched around for some time fo...
Hi, I have a c++/windows program that receives data from another c++ program via a WM_COPYDATA message. It is then supposed to use Sockets/winsock to send this message on to a server written in Java. The client connects to the server fine, but it doesn't seem to be able to send messages in a timely fashion. However, once the client is c...
Hi all, I have a c# dll and a c++ dll . I need to pass a string variable as reference from c# to c++ . My c++ dll will fill the variable with data and I will be using it in C# how can I do this. I tried using ref. But my c# dll throwed exception . "Attempted to read or write protected memory. ... This is often an indication that other m...
I'm not sure how to fix this or what I did wrong, but whenever I enter in a value it just closes out the run prompt. So, seems I do have a problem somewhere in my coding. Whenever I run the program and input a variable, it always returns the same answer.."The content at location 76 is 0." On that note, someone told me that "I don't kno...
I am writing an application needs to use large audio multi-samples, usually around 50 mb in size. One file contains approximately 80 individual short sound recordings, which can get played back by my application at any time. For this reason all the audio data gets loaded into memory for quick access. However, when loading one of these f...
Hey, what's the easiest way to convert a C++ std::string to another std::string, which has all the unprintable characters escaped? for example for the string of length two which the content 0x61,0x01 - the result string might be "a\x01", or "a%01" Just looking for the easiest already-implemented solution. Specific output format is les...
After learning good amount of c++, i'm now into STL containers and algorithms template library, my major concerns are, 1) Is this library same across different platforms like MS, linux n other os? 2) will quality or efficiency of program c++ module decrease with more use of STL containers and algorithms, i think i can't customize it to...
I wrote a function to count vowels. If there is a vowel at the end of the stream it gets counted twice. Why? #include <iostream> #include <string> #include <map> using namespace std; void countChars(istream& in, string theChars, ostream& out) { map<char, int> charMap; map<char, int>::iterator mapIt; for (string::iterator i = the...
I'm trying to read some OpenGL tutorials on the net. the problem is that I found some old ones that use gluPerspective(). gluPerspective was deprecated in OpenGL 3.0 and removed in 3.1. What function can I use instead? I'm using C++ with latest FreeGlut installed. ...
I am trying to represent a relation (table) in C++ code: The columns of the relation are integers. The number of columns in the relation is fixed at runtime. No duplicates should be allowed (this is the major source of cost). I want to have a map from names to relations. Any ideas for an efficient implementation, the main issue here ...
Hello, this code: template <class tB> struct A{ typedef float atype; typedef typename tB::btype typeB; }; template <class tA> struct B{ typedef float btype; typedef typename tA::atype typeA; }; struct MyB; struct MyA: public A<MyB>{}; struct MyB: public B<MyA>{}; int main(int argc, char *argv[]) { } does not compile because ...
I am pretty new to Ubuntu, but I can't seem to get this to work. It works fine on my school computers and I don't know what I am not doing. I have checked usr/include and time.h is there just fine. Here is the code: #include <iostream> #include <time.h> using namespace std; int main() { timespec time1, time2; int temp; c...
I'm working on project involving c programming for my mathematics course at university. I need to be able to handle large integers, larger than those that can be stored in a 'long int' datatype. So I tried using 'long long int', but if I try something like this: long long int number; number = 10000000000; Then the error message says ...
I currently have a program which use busy pooling and a bunch of thread to monitor states of object, process data, and pass data.. This is all very hard to manage/waste cpu time. I am looking at removing thread and using signal / slot as there is none of my code which "block". So I will signal states of my object, which is easy. What's ...