Questions tagged [c++]

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

Filter by
Sorted by
Tagged with
219
votes
9answers
23k 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 ...
200
votes
40answers
19k views

My Dad is impatient with the pace of my learning to program. What do I do? [closed]

So my Dad bought me 5 books on programming (C++, Java, PHP, Javascript, Android) about a month ago. He's an architect and he knows NOTHING about programming. He bought me them because I told him ...
192
votes
7answers
253k views

When do you use float and when do you use double

Frequently in my programming experience I need to make a decision whether I should use float or double for my real numbers. Sometimes I go for float, sometimes I go for double, but really this feels ...
170
votes
3answers
68k views

Is C++11 Uniform Initialization a replacement for the old style syntax?

I understand that C++11's uniform initialization solves some syntactical ambiguity in the language, but in a lot of Bjarne Stroustrup's presentations (particularly those during the GoingNative 2012 ...
164
votes
12answers
447k views

When to use C over C++, and C++ over C?

I've been introduced to Computer Science for a little over a year now, and from my experience it seems that C and C++ are both considered to be "ultrafast" languages, whereas others such as Python and ...
162
votes
19answers
191k views

Is there any reason to use C++ instead of C, Perl, Python, etc.? [closed]

As a Linux (server side) developer, I don't know where and why should I use C++. When I'm going for performance, the first and last choice is C. When "performance" isn't the main issue, programming ...
141
votes
11answers
22k views

Should I stop using the term C/C++?

I understand C and C++ are different languages but when I was learning C++ I was always told that C is a subset of C++ or C++ is C with classes. And that was quite true until the appearance of C++x0, ...
138
votes
15answers
28k views

Why did memory-managed languages like Java, Javascript, and C# retain the `new` keyword?

The new keyword in languages like Java, Javascript, and C# creates a new instance of a class. This syntax seems to have been inherited from C++, where new is used specifically to allocate a new ...
135
votes
8answers
82k views

What does C++ do better than D?

I have recently been learning D and am starting to get some sort of familiarity with the language. I know what it offers, I don't yet know how to use everything, and I don't know much about D idioms ...
132
votes
16answers
38k views

Why do people use C if it is so dangerous?

I am considering learning C. But why do people use C (or C++) if it can be used 'dangerously'? By dangerous, I mean with pointers and other similar stuff. Like the Stack Overflow question Why is ...
123
votes
14answers
29k views

Does auto make C++ code harder to understand?

I saw a conference by Herb Sutter where he encourages every C++ programmer to use auto. I had to read C# code some time ago where var was extensively used and the code was very hard to understand—...
118
votes
11answers
52k views

What backs up the claim that C++ can be faster than a JVM or CLR with JIT? [closed]

A reoccurring theme on SE I've noticed in many questions is the ongoing argument that C++ is faster and/or more efficient than higher level languages like Java. The counter-argument is that modern JVM ...
110
votes
13answers
19k views

Should we avoid language features that C++ has but Java doesn't?

Suppose I am limited to use C++ by the environment in the project. Is it good to prevent the use of some language features that C++ has but Java doesn't have (e.g.: multiple inheritance, operator ...
108
votes
4answers
12k views

Does a `long` ban make sense?

In today's cross-platform C++ (or C) world we have: Data model | short | int | long | long long | pointers/size_t | Sample operating systems ... LLP64/IL32P64 16 32 32 64 ...
102
votes
10answers
18k views

Is it ok to use meta-programming even though not all of my colleagues understand it?

I employ a lot of meta-programming to avoid repetitive tasks and build safer-to-use abstractions. I recently moved to a new job where I am working in a larger team and this worries some of my ...
100
votes
14answers
62k views

Why are most browsers developed in C++ [closed]

It seems like most of common web browsers (Firefox, Chrome, Safari) are developed using C++. Whys is that so?
100
votes
7answers
51k views

Why declare a variable in one line, and assign to it in the next?

I often see in C and C++ code the following convention: some_type val; val = something; some_type *ptr = NULL; ptr = &something_else; instead of some_type val = something; some_type *ptr = &...
98
votes
14answers
21k views

Is it bad practice to write code that relies on compiler optimizations?

I've been learning some C++, and often have to return large objects from functions that are created within the function. I know there's the pass by reference, return a pointer, and return a ...
91
votes
8answers
69k views

Is modern C++ replacing C#? Is Microsoft pushing developers to adopt C++? [closed]

I hear about modern C++ popularity and some talks about migrating back to C++ from C# or other C-like languages. I know about C++11 features but I would like to hear your experiences, especially from ...
85
votes
8answers
61k views

Is it better to document functions in the header file or the source file?

In languages that distinguish between a "source" and "header" file (mainly C and C++), is it better to document functions in the header file: (pilfered from CCAN) /** * time_now - return the ...
82
votes
11answers
11k views

Did the developers of Java consciously abandon RAII?

As a long-time C# programmer, I have recently come to learn more about the advantages of Resource Acquisition Is Initialization (RAII). In particular, I have discovered that the C# idiom: using (var ...
78
votes
15answers
32k views

Why would it ever be possible for Java to be faster than C++?

Sometimes Java outperforms C++ in benchmarks. Of course, sometimes C++ outperforms. See the following links: http://keithlea.com/javabench/ http://blog.dhananjaynene.com/2008/07/performance-...
78
votes
20answers
7k views

Is it ok to replace optimized code with readable code?

Sometimes you run into a situation where you have to extend/improve some existing code. You see that the old code is very lean, but it's also difficult to extend, and takes time to read. Is it a good ...
78
votes
5answers
27k views

Why are there no package management systems for C and C++? [closed]

There are some programming languages for which exist a package management system: CTAN for TeX CPAN for Perl Pip & Eggs for Python Maven for Java cabal for Haskell Gems for Ruby npm for NodeJS ...
77
votes
12answers
49k views

What's the benefit of object-oriented programming over procedural programming?

I'm trying to understand the difference between procedural languages like C and object-oriented languages like C++. I've never used C++, but I've been discussing with my friends on how to ...
76
votes
11answers
17k views

Why is base-for-all-objects discouraged in C++

Stroustrup says "Don’t immediately invent a unique base for all of your classes (an Object class). Typically, you can do better without it for many/most classes." (The C++ Programming Language Fourth ...
74
votes
6answers
51k views

Is `catch(…) { throw; }` a bad practice?

While I agree that catching ... without rethrowing is indeed wrong, I however believe that using constructs like this: try { // Stuff } catch (...) { // Some cleanup throw; } Is acceptable in ...
71
votes
19answers
4k views

Why should I care about micro performance and efficency?

Many questions and answers on the C/C++ pages, specifically or indirectly discuss micro performance issues (such is the overhead of an indirect vs direct vs inline function), or using an O(N2) vs O(...
69
votes
3answers
70k views

Why is Python written in C and not in C++? [closed]

In Python's tutorial one can read that Python's original implementation is in C; On the other hand, the Python implementation, written in C, (...) I'm very curious why was Python written in C and ...
69
votes
3answers
12k views

What's the reason for not using C++17's [[nodiscard]] almost everywhere in new code?

C++17 introduces the [[nodiscard]] attribute, which allows programmers to mark functions in a way that the compiler produces a warning if the returned object is discarded by a caller; the same ...
67
votes
10answers
16k views

Why do languages require parenthesis around expressions when used with “if” and “while”?

Languages like C, Java, and C++ all require parenthesis around an entire expression when used in an if, while, or switch. if (true) { // Do something } as opposed to if true { // Do ...
65
votes
13answers
15k views

Is it reasonable to null guard every single dereferenced pointer?

At a new job, I've been getting flagged in code reviews for code like this: PowerManager::PowerManager(IMsgSender* msgSender) : msgSender_(msgSender) { } void PowerManager::SignalShutdown() { ...
62
votes
3answers
38k views

Why do we need to put private members in headers?

Private variables are a way to hide complexity and implementation details to the user of a class. This is a rather nice feature. But I do not understand why in c++ we need to put them in the header of ...
61
votes
10answers
11k views

Is it bad practice to use a C++ compiler just for function overloading?

So I am working on a software design using C for a certain processor. The tool-kit includes the ability to compile C as well as C++. For what I am doing, there is no dynamic memory allocation ...
60
votes
7answers
65k views

Using scoped enums for bit flags in C++

An enum X : int (C#) or enum class X : int (C++11) is a type that has a hidden inner field of int that can hold any value. In addition, a number of predefined constants of X are defined on the enum. ...
59
votes
9answers
51k views

std::shared_ptr as a last resort?

I was just watching the "Going Native 2012" streams and I noticed the discussion about std::shared_ptr. I was a bit surprised to hear Bjarne's somewhat negative view on std::shared_ptr and his comment ...
59
votes
10answers
50k views

Is better Show() + Hide() or SetVisible(bool visible)?

What is better and why? (From interface-design point of view) : a) To have two Show() and Hide() functions b) To have one SetVisible(bool visible) function EDIT: For example some object have ...
59
votes
13answers
7k views

Philosophy behind Undefined Behavior

C\C++ specifications leave out a large number of behaviors open for compilers to implement in their own way. There are a number of questions that always keep getting asked here about the same and we ...
58
votes
17answers
9k views

What programming problems are best solved by using pointers? [closed]

Well, I basically understand how to use pointers, but not how best to use them in order to do better programming. What are good projects or problems to resolve involving the use of pointers so I can ...
58
votes
11answers
16k views

A modern review of Java [closed]

I've been programming for a few years and I began in Java, and in my time I've found many different sources claiming Java to be an inferior language in some way or another. I'm well aware that each ...
57
votes
9answers
8k views

Readability versus maintainability, special case of writing nested function calls

My coding style for nested function calls is the following: var result_h1 = H1(b1); var result_h2 = H2(b2); var result_g1 = G1(result_h1, result_h2); var result_g2 = G2(c1); var a = F(result_g1, ...
57
votes
7answers
43k views

Why is there no 'finally' construct in C++?

Exception handling in C++ is limited to try/throw/catch. Unlike Object Pascal, Java, C# and Python, even in C++ 11, the finally construct has not been implemented. I have seen an awful lot of C++ ...
56
votes
7answers
16k views

Why are there so many string classes in the face of std::string?

It seems to me that many bigger C++ libraries end up creating their own string type. In the client code you either have to use the one from the library (QString, CString, fbstring etc., I'm sure ...
56
votes
3answers
24k views

What is a lambda, and why would it be useful? [closed]

So far I heard about : Lambda calculus Lambda programming Lambda expressions Lambda functions Which all seems to be related to functional programming... Apparently it will be integrated into C++1x, ...
55
votes
15answers
5k views

Why do we have postfix increment?

Disclaimer: I know perfectly well the semantics of prefix and postfix increment. So please don't explain to me how they work. Reading questions on stack overflow, I cannot help but notice that ...
54
votes
10answers
14k views

Why would the 'final' keyword ever be useful?

It seems Java has had the power to declare classes not-derivable for ages, and now C++ has it too. However, in the light of the Open/Close principle in SOLID, why would that be useful? To me, the ...
54
votes
6answers
3k views

Function inadvertently invalidates reference parameter - what went wrong?

Today we found out the cause of a nasty bug that only happened intermittently on certain platforms. Boiled down, our code looked like this: class Foo { map<string,string> m; void A(const ...
52
votes
8answers
20k views

What happens to garbage in C++?

Java has an automatic GC that once in a while Stops The World, but takes care of garbage on a heap. Now C/C++ applications don't have these STW freezes, their memory usage doesn't grow infinitely ...
52
votes
5answers
18k views

Why are reference-counting smart pointers so popular?

As I can see, smart pointers are used extensively in many real-world C++ projects. Though some kind of smart pointers are obviously beneficial to support RAII and ownership transfers, there is also a ...
50
votes
3answers
20k views

Why are exception specifications bad?

Back in school some 10+ years ago, they were teaching you to use exception specifiers. Since my background is as one of them Torvaldish C programmers who stubbornly avoids C++ unless forced to, I only ...