Questions about C++, a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language.

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0
votes
0answers
26 views

Why does my c++ code run fine on Windows 7 but crashes on Windows 8? [migrated]

Ok, I added the following code to a mod menu for a game and everything works fine for me in Windows 7. But when I send it to my friend on Windows 8, he tries to select a button (which calls the ...
2
votes
2answers
76 views

Blocking function call with asynchronous content

I am sure that this is a common design pattern, but I seem to have a blind-spot. I have a requirement that the function call from Application to Service be blocking, but service needs to do ...
12
votes
7answers
286 views

When NOT to use virtual destructors?

I believed I searched many times about virtual destructors, most mention the purpose of virtual destructors, and why you need virtual destructors. Also I think in most cases destructors need to be ...
-1
votes
1answer
36 views

Qt connection Sql Server (universal connection string)

I am developing a software to connect to sql server. The problem is, ¿i don't know wich sql server is used?, and my question is ¿if exist a universal connection String?. I read many cases and in ...
0
votes
0answers
82 views

Member vs free function [duplicate]

I've read similiar topics and also the following great article: http://www.gotw.ca/publications/mill02.htm I'm still not quite sure how to apply it though. Basically I have a class that is an ...
21
votes
1answer
2k views

Why does C++ not have a “pure” keyword for virtual functions?

I have always wondered why we code virtual void MyFunction() = 0; and not pure virtual void MyFunction(); Is there a reference for the basis of this decision?
-3
votes
0answers
25 views

How to transfer signed integers with libusb? [on hold]

I want to communicate with an arduino and sent integers it. I code this program in C++. I initialy used bulk_transfer(), but it sends only 1 byte char data. I want to send signed integers. The ...
3
votes
3answers
189 views

Is this a good method to create class hierarchies?

Is it a good design to store the type of the object in the base class as an enum? For example, consider the following hierarchy Expr --Unary --Binary --Const ----Int ----Float How to represent the ...
0
votes
0answers
134 views

C/C++ for algorithm development [on hold]

I developed an algorithm and prototyped it in python. Now I need a high performance executable. I've never programmed in C/C++, but know they're the right tools for the job. I'd rather do it in C ...
-1
votes
0answers
33 views

Tcp server language choice [on hold]

Is there any reason to use a specific programming language for TCP server programming? Or java, c# can achieve same as c++ without any noticeable performance loss?
2
votes
2answers
147 views

Is there any advantage to c-style bit manipulation over std::bitset?

I work almost exclusively in c++11/14, and usually cringe when I see code like this: std::int64_t mArray; mArray |= someMask << 1; This is just an example; I'm talking about bit-wise ...
0
votes
3answers
231 views

What arguments are there to use a coding style for each distinct language? [duplicate]

I recently had a discussion about our coding style for C# projects. Two things in particular were very hard to agree upon. Method Naming C# has the de-facto standard of naming (at least public, ...
2
votes
1answer
120 views

Does the LGPL apply if I rewrite a portion of JasperReports in C++?

I would like to rewrite a portion of the JasperReports library in C++. The library will read from the same XML format used by JasperReports. If I integrate this C++ library to my proprietary ...
0
votes
3answers
178 views

Is there a use for non-const reference parameters?

Given a function like: void do_stuff( Thing & thing ) { // at this point, I can inadvertently or purposefully change thing } Is there a reason to purposefully change thing? Changing thing ...
0
votes
2answers
72 views

Should I set values using the return or by giving a reference?

Suppose I have a mouse position watcher, which should let the user extract the mouse position. Should the mouse position be set in the method and returned: Mouse_Position ...
3
votes
1answer
253 views

In C++, why does the main function use 'char *argv[]'?

I was wondering why C++ uses the following function prototype for the main() function: int main(int argc, char *argv[]); instead of something like: int main(std::vector<std::string> argv); ...
-3
votes
0answers
46 views

C++ or Python: Best investment for a Medic/Software developer who wants to do complex medical image analysis [closed]

I am an intermediate programmer who uses RoR and previously PHP to create web applications to aid my clinical research - I am a radiologist. I am trying to develop some image processing tools to ...
1
vote
1answer
90 views

A little confused with virtual functions

Please see the following code: #include<iostream.h> #include<string.h> class father { char fname[20]; public: father() { strcpy(fname,"eshwarappa"); ...
0
votes
0answers
46 views

data structure with best match lookup

Let me explain my question with one example: I have the following structs: struct Box{ unsigned char color; unsigned double width; unsigned double height; unsigned double weight; }; struct ...
0
votes
1answer
58 views

How Do I Create A Module* For A Class That Relies On Another Module?

*I'm using "Module" to mean some extension of a class, either through inheritance or composition. Say I have one of the following declarations of an Entity: using EUnit = int; class Entity : /*With ...
2
votes
1answer
69 views

C++: Make classes immutable or compatible with STL containers

Making types immutable is often desireable, especially for multi-threaded applications. There's no need to worry about concurrent access and no need for any synchronization. The common STL containers ...
1
vote
2answers
106 views

“Sweep” a vector of pointers

I'm using a vector to store pointers to objects. In some cases I destroy one or more of these objects (setting the vector spaces to NULL after each delete call), which are externally selected: for ...
0
votes
0answers
5 views

Undefined reference error [migrated]

I know that there are a lot of questions about undefined reference out there, but I couldn't find any that is like my case, probably because I am new to C++. I am developing a little project ...
0
votes
0answers
32 views

How to design an application with a settings widget [closed]

I have three major parts in my application. The main UI, the logic code, which is pretty well separated by MVC, and the settings UI. I have problems designing this bunch and I am constantly rewriting ...
-1
votes
0answers
17 views

Implement settings, common practice? [migrated]

Assume I save my settings of a widget with QSettings. How is QSettings meant to be used? As a member of my widget, accessed everytime one of the settings is used, or created and used once on widget ...
0
votes
1answer
87 views

AST processing and usefulness of visitor pattern

I know the visitor pattern is typically used to traverse a hierarchy of heterogeneous objects (inheriting a same abstract object) and dissociate the processing of these objects from the data within ...
2
votes
2answers
528 views

When and why should a destructor be declared as virtual?

As in class TestA { TestA(); virtual ~TestA(); } So why and when should the destructor for TestA be virtual??
2
votes
1answer
84 views

Including standard library headers only once across multiple program headers

I am writing a program with multiple headers and code files, as so: message.h message.cpp option.h option.cpp main.cpp message.h includes option.h as message.cpp requires the definition of the ...
2
votes
1answer
207 views

Refactoring code with just a few lines different

I have two for loops in a function which look like these: for (int i=0; i < MAX; ++i) { identical_lines identical_lines identical_lines first_for_specific_line identical_lines ...
1
vote
2answers
119 views

Is returning a reference to inside a private vector bad practice?

I have the following trimmed class: #include <vector> #include "Tile.h" class Board { std::vector<Tile> boardArr; // VVV Bad Practice? Safe? Tile& getTileAt(unsigned ...
2
votes
2answers
138 views

Alternative to using getters/setters in a simple class

I'm writing a minesweeper game with curses. To represent each tile, I wrote small Tile class that contains information about the possible state of each tile (whether or not it's flagged, whether or ...
2
votes
0answers
57 views

Heavy-duty use of C++ initializer_lists of containers [closed]

I've proposed and developed an optimization bringing move semantics to std::initializer_list. It seems like a slam dunk, but some on the committee saw the proposal as a waste of time, never mind ...
4
votes
1answer
227 views

How does modulus work?

I am not asking asking how the mathematical concept of modulus works, or how 20 % 3 == 2 I understand this fine. I'm more curious how the compiler/interpreter determines this. I can think of a very ...
-1
votes
0answers
21 views

Using Command Line Arguments to Choose a Datatype? [migrated]

Basically, based on whether a user inputs a 0 or 1 as a command line argument, I want my data class to either have a vector or an array (static) as its data member. I don't believe you can add if ...
0
votes
2answers
138 views

Style question: To use overloaded version or not?

Let's say I had an operator() overload that made temp_.matrix[k][j] and temp_(k+1, j+1) equivalent. In my class functions (where matrix belongs), would it be better to have if (temp_.matrix[k][j] == ...
-1
votes
0answers
27 views

how to create a char array in c++? [migrated]

I am trying to create a pointer to a char and pass it to function as a char*. here is my code to define the char array it seems the compiler does not recognize the end of the string because the ...
4
votes
4answers
256 views

What makes a program cross-platform or not?

I have fairly basic programming experience with Java and I've tried C++ and Python. While it makes sense for Java, the basic programs I've written in C++ have run just fine on Windows and OS X. I've ...
0
votes
0answers
38 views

Difficulty designing my EventHandler class that uses a callback to handle key-presses

I wrote an EventHandler class that takes a std::function<void(char)>, and a std::vector<char> of chars (representing keys). If a key in the vector is pressed, the call-back is executed ...
-2
votes
0answers
25 views

Addition and Subtraction giving incorrect results [migrated]

I made a simple program to add and subtract the given numbers. Let's say the 2 numbers give were 5 and 5. It would print 5 + 5 = 10 and 5 - 5 = 0. Right now I'm not sure what's wrong. I might need a ...
-2
votes
0answers
59 views

The correct way to use a for loop in an array C++ [migrated]

I'm having some trouble with a homework assignment dealing with Arrays. I have already read all the text from class (which didn't help me at all), looked up several tutorials on arrays, and searched ...
-2
votes
0answers
16 views

Using getline() with parameters to read through a file and extract specific information? [migrated]

I'm programming a c++ console application for school and I need to read through a .txt file to extract specific informations to use them in classes. For example, here is a portion of the txt file : ...
0
votes
3answers
190 views

Compile-time vs. run-time configuration

I'm starting new project and need to decide on how to handle configuration. I recently run into suckless project. While it has its own issues, I really liked its approach to configuration - just a ...
6
votes
2answers
209 views

Static console object or dependency injection?

For a current project I have created a Console class which wraps up C++'s usual cout, writes output to a file or uses Console::WriteLine depending on the environment. Currently I've setup my code base ...
1
vote
1answer
138 views

Are there real world examples demonstrating reasonable performance improvement by using move semantics?

(I've asked a similar question on SO but unfortunately it might not be proper, so I also put here; please kindly point out if you think it's a duplicate.) I've heard many words about the move ...
-1
votes
2answers
173 views

Mermaid problem (OOP) [closed]

A Mermaid is half fish and half human. It has upper human body and lower fish body. When under water its upper part swims like a human while its lower part swims like a fish. Please explain how can it ...
2
votes
3answers
351 views

In C++, should I ever declare a local variable in the corresponding header?

So for example, I create a class with two functions: foo.h class foo { public: foo(); void bar(); void ey(); bool m_memberBool; bool localBool; // ??? Should I put this here? }; ...
-1
votes
1answer
49 views

One symbol - one meaning?

It's well known recomendations that: 1) class or function should have one responsibility 2) variable should not be reused in different contexts We can generalize this recomendations to general ...
6
votes
8answers
688 views

Structuring Procedural vs OO code

I have spent the vast majority of my programming career using Java and very OO based C++. I am really interested in learning to think more procedurally, so I have been starting to do some practice ...
1
vote
0answers
80 views

Is the behaviour of floating-point arithmetic defined by the c++ standard?

I started writing this as a SO question but I think it's better suited here. While I'm happy for simply an answer I'm also fond of the "Teach a Man to Fish" phylosophy so I'm happy for people to point ...
2
votes
0answers
63 views

Can't figure out class scheduling issue? [closed]

"You are a college advisor trying to help students plan their academic careers. You have the list of courses in each major and their prerequisites. Students often want to take their major courses as ...