c++

C++ packing a typedef enum

typedef enum BeNeLux { BELGIUM, NETHERLANDS, LUXEMBURG } _ASSOCIATIONS_ BeNeLux; When I try to compile this with C++ Compiler, I am getting errors, but it seems to work fine with a C compiler. So here's the question. Is it possible to pack an enum in C++, or can someone see why I would get the error? The error is: "semico...

What was Tim Sweeney thinking? (How does this C++ parser work?)

Tim Sweeney of Epic MegaGames is the lead developer for Unreal and a programming language geek. Many years ago posted the following screen shot to VoodooExtreme: As a C++ programmer and Sweeney fan, I was captivated by this. It shows generic C++ code that implements some kind of scripting language where that language itself seems to b...

C++ exam question on string class implementation

I just took an exam where i was asked the following: Write the function body of each of the methods GenStrLen, InsertChar and StrReverse for the given code bellow. You must take into consideration the following; How strings are constructed in C++ The string must not overflow Insertion of character increases its length by ...

Why can't I access a const vector with iterator?

My example is as below. I found out the problem is with "const" in function void test's parameter. I don't know why the compiler does not allow. Could anybody tell me? Thanks. vector<int> p; void test(const vector<int> &blah) { vector<int>::iterator it; for (it=blah.begin(); it!=blah.end(); it++) { cout<<*it<<" "; } }...

initializer_list not working in VC10

hi i wrote this program in VC++ 2010: class class1 { public: class1 (initializer_list<int> a){}; int foo; float Bar; }; void main() { class1 c = {2,3}; getchar(); } but i get this errors when i compile project: Error 1 error C2552: 'c' : non-aggregates cannot be initialized with initializer list c:\users\pswin\documents...

Boost.Python wrapping hierarchies avoiding diamond inheritance

I'm having some trouble seeing what the best way to wrap a series of classes with Boost.Python while avoiding messy inheritance problems. Say I have the classes A, B, and C with the following structure: struct A { virtual void foo(); virtual void bar(); virtual void baz(); }; struct B : public A { virtual void quux(); }...

variable scope when adding a value to a vector in class constructor

I have a level class and a Enemy_control class that is based off an vector that takes in Enemys as values. in my level constructor I have: Enemy tmp( 1200 ); enemys.Add_enemy( tmp ); // this adds tmp to the vector in Enemy_control enemys being a variable of type Enemy_control. My program crashes after these statements complaining abou...

Finding the centroid of a polygon?

I have tried: for each vertex, add to total, divide by number of verities to get center. I'v also tried: Find the topmost, bottommost -> get midpoint... find leftmost, rightmost, find midpoint. Both of these did not return the perfect center because I'm relying on the center to scale a polygon. I want to scale my polygons so I may put...

use qt and django to create desktop apps

Hi guys, I had this idea of creating desktop apps using django. The principe being: - Write the django app, and use something like cherrypy to serve it. - Write a Qt app in C++ to access it and this by using QtWebview (webkit) I'd like to "bundle" this in a single app. The lighter, the better :) So here are my questions and if you have...

Compiling a Windows C++ program in g++

I'm trying to compile a Windows C++ program in g++. This is what I get. /usr/include/c++/4.4/backward/backward_warning.h:28:2: warning: #warning This file includes at least one deprecated or antiquated header which may be removed without further notice at a future date. Please use a non-deprecated interface with equivalent functionalit...

library for simple GUI appications

I tried to use WTL, but i couldn't make it to work on VS2008 Express, there is any other option? I would like to test if any, before recur to the plain API :/ need to be small and have no external dependencies Thanks in advance! ...

How to use gdb to find a floating point exception in g++ code

I have a g++ program that runs without user input. Somewhere the program is interrupted and it says "Floating point exception." Can gdb help me find what's causing this in my code? How? ...

Accessing a webpage in C++

Is there a good, simple library which allows C++ to load a webpage? I just want to grab the source as text. I'm not using any IDE or significant library, just straight command line. Tangentially, is there something fundamental I'm missing about programming in C++? I would think any language in common use today would have droves of web-b...

C++ HW - defining classes - objects that have objects of other class problem in header file (out of scope?), (also redefining operators, read in out)

This is my first time with much of this code. With this instancepool.h file below I get errors saying I can't use vector (line 14) or have instance& as a return type (line 20). It seems it can't use the instance objects despite the fact that I have included them. #ifndef _INSTANCEPOOL_H #define _INSTANCEPOOL_H #include "instance.h" #inc...

C++ - Print Out Objects From Set

If I have a C++ set and iterator: set<Person> personList; set<Person>::const_iterator location; How can I print out the contents of the set? They are all person objects, and I have overloaded operator<< for Person. The line that errors is in a basic for loop: cout << location Netbeans gives: proj.cpp:78: error: no match for ‘o...

removing subset transactions form file

I have a file containing data as follows 10 20 30 40 70 20 30 70 30 40 10 20 29 70 80 90 20 30 40 40 45 65 10 20 80 45 65 20 I want to remove all subset transaction from this file. output file should be like follows 10 20 30 40 70 29 70 80 90 20 30 40 40 45 65 10 20 80 Where records like 20 30 70 30 40 10 20 45 65 ...

Need help in reading callgrind output

Hi, I have run callgrind with my application like this "valgrind --tool=callgrind MyApplication" and then call 'callgrind_annotate --auto=yes ./callgrind.out.2489' I see output like 768,097,560 PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function ------------------...

Seeking to a line in a file in g++

Is there a way that I can seek to a certain line in a file to read or write data? Let's say I want to write some data starting on the 10th line in a text file. There might be some data already in the first few lines, or the file could even be empty. Is there a way I can seek directly to the line I want without having to worry about wh...

two classes contain objects of each other

hi, i hope there's a simple answer to this. without getting too complicated i have two classes. an "Animal" and a "Cell" Cell contains an Animal as a member. Animal has methods that accept Cells in their parameters. i'm just confused as to how i #include each class the others header? i've only ever had to go up a chain of classes and ju...

Dynamic allocating of const member structures

I've got class which is using plain-only-data struct with const variables and I'm not sure, if I'm allocating these structures in a proper way. It looks more or less like: #include <cstdlib> #include <iostream> using std::cout; using std::endl; struct some_const_struct { const int arg1; const int arg2; }; class which_is_usi...