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

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7
votes
4answers
1k views

Avoid having an initialization method

I have this existing code where they have a class and an initialization method in that class. It is expected that once the object of the class is created, they need to call initialize on it. Reason ...
1
vote
1answer
154 views

Best solution to switch between new and deprecated code

We have a feature that is currently implemented, let's call it implA. ImplA works but can't do many things. So we have decided to rewrite it. But we can't just replace it right away, so we will need ...
0
votes
0answers
101 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 ...
1
vote
2answers
136 views

How can I have objects interacting and communicating with each other without forcing a hierarchy?

I hope these ramblings will make my question clear — I'd totally understand if they wont, though, so let me know if that's the case, and I'll try making myself clearer. Meet BoxPong, a very ...
18
votes
5answers
3k views

Why do all <algorithm> functions take only ranges, not containers?

There are many useful functions in <algorithm>, but all of them operate on "sequences" - pairs of iterators. E.g., if I have a container and like to run std::accumulate on it, I need to write: ...
15
votes
7answers
2k 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 ...
6
votes
5answers
3k views

Alternate string formatting options in C++?

I'm looking at optimizing some string formatting code that's hit a lot in our code. We had been using ostringstream, and I converted the code to use sprintf (actually Microsoft's more secure ...
5
votes
2answers
521 views

Is it possible to refactor inheritance to composition when virtual methods are called inside the base class?

Let's say I have a class called Country and two subclasses called AI and Player. The Country class has a number of virtual methods to allow player-specific or AI-specific behavior. I want to make it ...
26
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?
16
votes
2answers
3k views

What's RAII? Examples?

Always when the term RAII is used, people are actually talking about deconstruction instead of initialisation. I think I have a basic understanding what it might mean but I'm not quite sure. Also: is ...
24
votes
3answers
4k views

C++ strongly typed typedef

I've been trying to think of a way of declaring strongly typed typedefs, to catch a certain class of bugs in the compilation stage. It's often the case that I'll typedef an int into several types of ...
0
votes
4answers
20k views

2 Dimensional Arrays in C++

I started learning arrays in C++ and came over a little side note in the book talking about 2D arrays in breif. I tested it out and i was amazed that it could give the programmer the ability to store ...
3
votes
3answers
215 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 ...
2
votes
2answers
275 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
249 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, ...
0
votes
3answers
224 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 ...
15
votes
5answers
6k views

If a variable has getter and setter, should it be public?

I am an about to graduate Computer Science student so probably this is a stupid question. If I have a class with a variable that is private and the class have getter and setter for that variable. Why ...
2
votes
3answers
206 views

Disallow non-local storage of an object

I need to write a class in C++ that acquires a hardware resource and releases it again when it is destroyed. Basically that can be done in the constructor and destructor of the class. The difficulty ...
2
votes
1answer
141 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 ...
3
votes
1answer
261 views

How can I use the “Non-Member Functions Improve Encapsulation” pattern from C#?

In 2000, Scott Meyers argued that non-member functions improve encapsulation. In C++, a non-member function is a C-style global function: ...
0
votes
2answers
91 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
287 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); ...
7
votes
3answers
11k views

What is meant by Scope of a variable?

I think of the scope of a variable as - "The scope of a particular variable is the range within a program's source code in which that variable is recognized by the compiler". That statement is ...
1
vote
1answer
98 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
1answer
64 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 ...
0
votes
0answers
76 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 ...
2
votes
1answer
108 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
127 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
1answer
175 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
554 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??
6
votes
8answers
830 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 ...
3
votes
1answer
126 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
220 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 ...
0
votes
2answers
1k views

Visual Studio c++ Windows forms? [closed]

I've been slacking off with learning how to program because I'm at my wits end trying to figure out the next step. I want to be able to create forms applications just to test random things and give ...
1
vote
2answers
192 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
193 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 ...
4
votes
3answers
577 views

Intersection of geometric entities

I was trying to design a small C++ geometric API for learning purposes, but came across a problem when dealing with intersections of geometric entities. For example, the intersection of a line and a ...
5
votes
2answers
2k views

Every function is a closure?

Wikipedia says, that closure - is a function, which has an access to variables, declared outside of the function. There is even an example: function startAt(x) function incrementBy(y) ...
4
votes
1answer
289 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 ...
0
votes
2answers
143 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] == ...
15
votes
7answers
3k views

Are header files actually good? [closed]

I find header files to be useful when browsing C++ source files, because they give a "summary" of all the functions and data members in a class. Why do so many other languages (like Ruby, Python, ...
4
votes
4answers
299 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
62 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 ...
4
votes
4answers
3k views

C++ Iterator lifetime and detecting invalidation

Based on what's considered idiomatic in C++11: should an iterator into a custom container survive the container itself being destroyed? should it be possible to detect when an iterator becomes ...
30
votes
8answers
3k views

The “blub paradox” and c++

I was reading the article here: http://www.paulgraham.com/avg.html and the part about the "blub paradox" was particularly interesting. As someone who mainly codes in c++ but has exposure to other ...
0
votes
3answers
324 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 ...
173
votes
9answers
12k views

Why do many exception messages not contain useful details?

It seems there is a certain amount of agreement that exception messages should contain useful details. Why is it that many common exceptions from system components do not contain useful details? A ...
5
votes
2answers
3k views

Refactoring C++ [closed]

I know that there are some other questions about C++ refactoring, but none satisfies my needs. I have a background in Java and Python programming, but now I'm approaching C++. I've read (and ...
11
votes
6answers
2k views

Homework for strong C++ developers learning Java [closed]

I'm tasked with teaching an accelerated university special topics course in Java for programmers with many years of experience in C/C++. What sort of medium-length (1-2 hours max) assignments would ...
11
votes
5answers
1k views

How to migrate my thinking from C++ to C#

I am an experienced C++ developer, I know the language in great details and have used some of its specific features intensively. Also, I know principles of OOD and design patterns. I am now learning ...