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

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0
votes
1answer
100 views

How shall I handle event loop exceptions?

What is the best practice for handling exceptions thrown from event handlers/listeners in a event loop? For example: class EventLoop { public: void start(); //create a thread which calls run(); ...
1
vote
1answer
172 views

Why does this algorithm work in O(n m)?

This is from a blog post on Codeforces. I couldn't really understand why the editorialist goes on to claim that this code works in O(n m) This is a graph problem, where we are supposed to find the ...
1
vote
2answers
151 views

Why does this implementation of Dijkstra's algorithm work in O(n^2)?

Here is the code I use for implementing Dijkstra's algorithm. Consider a graph with n vertices and m edges. Shouldn't it run in O(n^2 m) ? Someone may say that there are n vertices and each edge gets ...
-3
votes
1answer
242 views

If-else in C++ Programming Language [closed]

I am a little bit confused about this code. Why does the else block get executed? Please explain it. int a=10,b=20; char x=1,y=0; if(a,b,x,y){ cout << "A" << endl; }else{ cout ...
1
vote
1answer
170 views

Using streams to connect programming languages

I'm trying to run a computation-heavy program that creates an image on a website. Is it possible to compute in C++ and have an output stream that connects to an input stream in Node.js to display an ...
1
vote
0answers
58 views

Maximizing reuse out of a function primitive in CUDA

I'm working on the implementation of a few related algorithms in CUDA, all of which require a primitive that we'll call f(). The related algorithms can't simply call f though, as they require f to ...
2
votes
1answer
144 views

Genetic Algorithm's Tournament Selection limit to be selected

I started working again on a Genetic Algorithm and i'm trying a lot of operators and ways of selection. When I made the Tournament Selection , I noticed that it gets really easy to always get the top ...
2
votes
1answer
157 views

Insertion sorting Algorithm comparison

I recently came across sorting techniques and of particular, 'insertion sorting'. Although the logic and method is fairly understandable, the actual function seemed a bit complex (given below). ...
1
vote
1answer
136 views

C++ Template Metaprogramming and Call By Need Evaluation

I recently wrote a fairly complex C++ meta function that boils down to: template <size_t N, typename val> struct Rec { using type = typename std::conditional<N == 0, val, ...
3
votes
3answers
480 views

Should I try it straight or should I first check if it can be done?

I have a set of items, and each item in the set must be unique. Item are composed from multiple properties and each property of each item can be changed. But after each change every item in the set ...
4
votes
1answer
274 views

What is the status of @ and $ characters in C++?

C++ syntax uses almost all printable ASCII characters and some of them in several contexts. Only two unused are @ and $ characters. Why they are not used? Are they reserved for some "meta" purpose?
3
votes
4answers
395 views

Are `switch` statements generally used wrong? [closed]

I see most developers using switch statements with breaks in each and every case. Is this usage of switch statements inappropriate since a simple set of if-else statements would suffice? Is it OK for ...
3
votes
0answers
213 views

How do you pronounce 'char' keyword? [closed]

So, with the possibility of this question being closed due to being non-productive as in the case of other pronunciation questions, I take the risk and ask it just because i have heard it said both ...
1
vote
2answers
85 views

Class as resource handle & Bad Copy

I am reading Bjarne Stroustrup's book titled "A tour of C++". The following section is confusing to me: When a class is a resource handle – that is, when the class is responsible for an object ...
-1
votes
1answer
64 views

What are some hashmaps we can easily implement? [duplicate]

At many places, I read that we can use HashMap here for O(1) search. Actually, I want to ask how I can implement easy hashmaps which can satisfy this property. Can anyone tell few hashmaps including ...
1
vote
1answer
108 views

Constructor vs casting operator

I'm programming a library (so I have complete access to all the mentioned classes). Two classes (A and B) are essentially the same and differ only by their implementation, so they can be easily ...
4
votes
1answer
173 views

Designing interfaces to hardware

I am writing a library in C++ that is used by customers to interface with hardware. There are many different devices that I need to support. For the sake of simplicity, assume I have 2 Widgets, ...
8
votes
5answers
887 views

How to structure a loop that repeats until success and handles failures

I am a self-taught programmer. I started programming about 1.5 years ago. Now I have started to have programming classes in school. We have had programming classes for 1/2 year and will have another ...
9
votes
7answers
974 views

Will a profound knowledge of C++ help you in learning other languages faster/easier? [closed]

Is there a possibility that someone who has learned all the key aspects of C++ and knows the fundamentals of the language very well, will learn other languages (such as, Python, Perl, Java) faster and ...
-2
votes
2answers
378 views

What is the simplest and universal algorithm for parsing C++ code? [closed]

I need to do some project specific automatic checking of source codes written in C++ Limitations: Algorithm and its implementation should be simple, easily maintainable, extendable and ...
3
votes
2answers
200 views

Is it always safe to shift bool values?

I stumbled about a Cppcheck warning (an inconclusive one), that I mistakenly used & instead of &&: /// @param code identifies the command. Only the lower 16 bits of are being processed ...
0
votes
3answers
57 views

Defining resource allocation in method documentation

I want to write a library with "no resource leak guarantee" feature. So I shall know whether each method allocates any resource or not. It may change the code. For example: void foo() { ...
4
votes
2answers
229 views

Needs (in principle) C++ parenthesis around if statement condition?

In current C++ when body of if statements contain only one command then: Parenthesis around if condition are mandatory but block are optional. So, both examples are OK: if ( condition ) { return 0; ...
2
votes
2answers
166 views

Use of raw pointer of std::vector

I am currently maintaining a code that makes liberal use of raw pointers where std::vector would be a better option. Worse, these pointers are not always properly handled (when run using Intel ...
3
votes
2answers
176 views

How to deal with historic exception specifications in maintained C++ code

Today, I discovered a few exception specifications in legacy code I've to maintain, when Cppcheck 1.68 ([Inconclusive] but correctly) pointed out that the specified exceptions are not handled in ...
0
votes
0answers
103 views

Requesting information regarding the use of MUI vs. the use of GetText for i18n/L10n of Windows desktop applications

I have spent the past two days investigating which technology I will use to support translations of text strings (as part of an overall internationalization migration) for an archaic (VC6) Windows ...
1
vote
1answer
177 views

Where should I place a typedef when used in method signatures in C++?

I'm using an Optional class quite similar to that of boost. For semantic reasons, I switched an attribute of the same (structured) type in some class definitions (and therefore also in method ...
2
votes
3answers
3k views

Efficient algorithm to count number of substrings divisible by 3

Given a string of decimal digits, I have to find the number of all substrings divisible by 3 in the range L to R [both inclusive], where L & R are index[1-based] of the specified string string ...
0
votes
1answer
76 views

Is it possible to save and load a decorated object

I am wondering if there is an easy way to save and load a decorated object in c++ as i have never done file handling in C++ before. Currently the only object type I need to save is objects that ...
2
votes
1answer
82 views

How to make max-heap stable with counter and account for counter overflow?

Generally I need size-efficient data structure similar to std::priority_queue but stable (preserving order of insertion). By adding just 4 bytes to the object I could have 1 byte serving as priority ...
1
vote
2answers
154 views

Unsure about the decorator design pattern

I'm fairly new at using design patterns and I am currently making a small game for my uni course that I have to use the decorator pattern for creating the different classes of NPC however I think that ...
24
votes
9answers
3k views

What is different between the internal design of Java and C++ that lets C++ have multiple inheritance? [duplicate]

It's drilled into the newbie Java programmers that Java (pre-Java 8) has no multiple class inheritance, and only multiple interface inheritance, because otherwise you run into diamond inheritance ...
0
votes
0answers
50 views

Mailbox Pattern with Variable Arguments in C++

In a game I'm developing, the GUI thread is catching user actions, and the simulation thread is responsible of handling and responding to them. To minimize complexity and delay, I predefined all ...
1
vote
2answers
91 views

How do you decide member objects?

So OOP is about breaking down functionality, making each class responsible for one thing etc. But let's take the example where an object is using another object. First thing that comes to mind ...
4
votes
2answers
403 views

Is the rule of 5 a valid extension of the rule of 3, or does it imply premature optimization?

I'm familiar with the notion in c++ of the rule of 3, however since the release of C++11 I've seen some sources suggesting it should be extended to a "rule of 5", I.e. the move constructor and move ...
0
votes
1answer
98 views

Passing by argument vs keeping it as a member

I really cannot decide what option is the best, I see plenty of down/upsides to both approaches and right now I'm undecided. For example; class DX11GBuffer { public: DX11GBuffer(ID3D11DevicePtr ...
0
votes
1answer
215 views

The difference between *s.pd and s->pd

I was reading about copy constructors for structs and i found this example: #include <iostream> #include <string> using namespace std; struct SomeData { int * pd; string id; ...
2
votes
5answers
521 views

Why lambda/closures expressions came so late to C++?

I was reading a really great Bjarne Stroustrup's article where he exposes some C++ myths. I look at code that focus my attention, because I wouldn't know that C++ supports this kind of expressions. ...
12
votes
3answers
2k views

Non-Object Oriented Programming in Object Oriented Language [closed]

Recently I was assigned a task of creating a calculator with functions addition, subtraction, multiplication, division and power using Object Oriented Programming. I successfully completed this task. ...
3
votes
3answers
403 views

How to use multiple programming languages together in the same program? [closed]

Such a simple question, but I have not found a reasonable answer to this. I currently program in Python, an interpreted language. I always hear of people using multiple languages in the same program? ...
9
votes
5answers
236 views

Correctly disposing objects upon server termination

I am working on a large C++ project. It consists in a server that exposes a REST API, providing a simple and user-friendly interface for a very broad system comprising many other servers. The codebase ...
4
votes
1answer
185 views

Why define struct in variable?

Consider the following program: Many people when they want to use a struct, they create a new variable as: struct structureName variableName While it works when you just define it as: ...
2
votes
1answer
168 views

Most efficient/cleanest way to Kill a recursive thread safely

I have a number of worker threads which all perform a flood-fill task on different regions of a bitmap. They all make calls to a recursive sub-routine with different parameters(coordinates). Fyi, I am ...
2
votes
2answers
385 views

OpenGL vs OpenCV for beginner [closed]

I am a freshman college student currently learning C++ programming. I am good at math and physics, so I am looking to specialize in 2D/3D graphics with OpenGL. My question is about the differences ...
1
vote
2answers
259 views

How to Keep Track of Thread Safe Code in a mostly Thread Unsafe Legacy Rich C++ Code Base

For large legacy C++ code bases, notions like Herb Sutter's "const means threadsafe" don't seem to help much, because there can be an overwhelming amount of code in const functions which are modifying ...
6
votes
3answers
190 views

Passing parameters that need to be copied by value or const reference

I have a basic (mathematical) vector class, which in my opinion benefits from C++'s operator overloading. Vector-scalar operations are defined as self-modifying functions in the class itself, class ...
4
votes
2answers
552 views

Isn't there a chicken-and-egg issue since GCC is written in C++ itself?

Since 4.8 release, the C++ compiler GCC (the G++ part of it) is written not in C anymore, but in C++ itself. I have a hypothetical question on this. I wonder how to compile the C++ code of GCC on a ...
0
votes
0answers
70 views

Design of a datamodel in a OO way

I'm looking for some advice how to design a datamodel in OO way (C++ in special). My problem: The user input in runtime is a 1D matrix A = (a0,...,an). The program creates - on the basis of A - ...
7
votes
1answer
184 views

Message Queue for RTOS for microcontrollers

I'm currently writing an RTOS for microcontrollers. The whole thing is written in C++11 - if anyone is interested, and the link to the repository is at the bottom. Currently I'm writing a class that ...
0
votes
1answer
109 views

Introducing function waypoints to protect device [closed]

Defining a magic pointer or counter inside a program / class and checking for a fixed value before executing critical commands is a way to generate a barrier against wrong execution. This check is ...