I have a project that has a GUI (written in QT) and a command-line version. I made use of the rectangle class included in QT: QRect. I would like to break the command-line version's dependency on QT, so I need a drop-in rectangle class that supports intersection and union. I could write one, but I'd prefer including one if possible. ...
Sorry to put a post up about something so simple, but I don't see what I'm doing wrong here. char data[1024]; DWORD numRead; ReadFile(handle, data, 1024, &numRead, NULL); if (numRead > 0) printf(data, "%.5s"); My intention with the above is to read data from a file, and then only print out 5 characters. However, it prints out al...
Maybe this is a compiler specific thing. If so, how about for gcc (g++)? If you use a variable reference/alias like this: int x = 5; int& y = x; y += 10; Does it actually require more cycles than if we didn't use the reference. int x = 5; x += 10; In other words, does the machine code change, or does the "alias" happen only at the ...
I need to calculate an ntp time stamp using gettimeofday. Below is how I've done it with comments on method. Look good to you guys? (minus error checking). Also, here's a codepad link. #include <unistd.h> #include <sys/time.h> const unsigned long EPOCH = 2208988800UL; // delta between epoch time and ntp time const double NTP_SCALE_FRAC...
I have a derived derived class from an abstract class. The code is below. I have a FishTank class which is derived from an Aquarium and Aquarium is derived from item. My question is that should I put the definition of virtual int minWidth() const = 0; in aquarium again or is the code below sufficient? class Item{ public: virtual int ...
I thought one of the best ways to familiarise myself with C/C++, is to make a helpful library. I was maybe thinking like a geometry library, like to calculate areas, surface area, etc. It would be useful in game programming. Or maybe an algebra library, like for different formulas like the distance formula, quadratic formula, etc. Or may...
Most common re-usable reference counted objects use private inheritance to implement re-use. I'm not a huge fan of private inheritance, and I'm curious if this is an acceptable way of handling things: class ReferenceCounter { std::size_t * referenceCount; public: ReferenceCounter() : referenceCount(NULL) {}; Referenc...
I am creating a GUI to manipulate a robot arm. The location of the arm can be described by 6 floats (describing the positions of the various arm joints. The interface consists of a QGraphicsView with a diagram of the arm (which can be clicked to change the arm position - adjusting the 6 floats). The interface also has 6 lineEdit boxes,...
Let's say that I have an application frame, and I want to show a popup QCalendarWidget over on the right side of the frame. Normally, QT will clip the edges of the QCalendarWidget, cutting it in half and not displaying the rest, as it would be over the right side border. Is there a way to work around this limitation without resorting ...
How to implement a static function in an abstract class?? Where do I implement this? class Item{ public: // // Enable (or disable) debug descriptions. When enabled, the String produced // by descrip() includes the minimum width and maximum weight of the Item. // Initially, debugging is disabled. static enableDebug(bool); }; ...
This is a very very basic question and I know one way is to do the following: char buffer[33]; itoa(aq_width, buffer,10); where aq_width is the int, but then I can't guarantee what size of buffer I would need in order to do this... I can always allocate a very large buffer size, but that wouldn't be very nice... any other pretty and s...
I have some odd self modifying code, but at the root of it is a pretty simple problem: I want to be able to execute a jmp (or a call) and then from that arbitrary point throw an exception and have it caught by the try/catch block that contained the jmp/call. But when I do this (in gcc 4.4.1 x86_64) the exception results in a terminate...
I'm trying to include : #include <commctl.h> into my win32 API program; however, it looks like it does not exist. What is the problem ? ...
Also, how does it compare to throwing an exception when something goes wrong ? ...
Hello everyone! I am trying to use Netbeans 6.7 (on a Mac) to create C++ applications. I started out with the standard "Hello World," just to test if everything was working correctly. First try std and could not be found. So I tried reinstalling the developer tools on my Mac OS X disk. After that Netbeans updated its c++ compiler info,...
What is the proper way to remove elements from a C++ vector while iterating through it? I am iterating over an array and want to remove some elements that match a certain condition. I've been told that it's a bad thing to modify it during traversal. I guess I should also mention that this is an array of pointers that I need to free befo...
I have the following code: void foo() { vector<double> v(100,1); // line 1 // some code v = vector<double>(200,2); // line 2 // some code } what happened to the vector of size 100 after the second line? Is it gets cleared by itself? If the answer is yes, how and when it is cleared? By the way, is there any o...
Hi, Just a quick question. I've written some code that returns a custom class Command, and the code I've written seems to work fine. I was wondering if there are any reasons that I shouldn't be doing it this way. It's something like this: Command Behavior::getCommand () { char input = 'x'; return Command (input, -1, -1); } Any...
Who can give me a link for the operator= of vector in MSDN? Why I can only find operator[]? If operator= is just something default, like copy everything in A to B, how this following code works? vector<double> v(100,1); v = vector<double>(200,2); // if operator= is just a trivail version, how to make sure the old v get cleared? ...
'??' gets converted into '^' if I compile mn VC++ program and run it e.g. sprintf( ch, "??") prints out ^ But if I run the same code in Turbo C/C++, there is no such problem. Why is it happening on VC++ on Windows? ...