Questions tagged [c]

C is a general-purpose computer programming language used for operating systems, games and other high performance work.

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210
votes
5answers
265k views

How to write a very basic compiler

Advanced compilers like gcc compile codes into machine readable files according to the language in which the code has been written (e.g. C, C++, etc). In fact, they interpret the meaning of each codes ...
192
votes
7answers
252k 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 ...
181
votes
8answers
55k views

Is every language written in C?

Sometimes while programming in different languages (C/C++, C#), this thought comes to my mind: Is each and every language written in the C programming language? Is the C language the mother/father ...
164
votes
12answers
446k 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 ...
151
votes
7answers
25k views

Was the C programming language considered a low level language when it came out?

Currently C is considered a low level language, but back in the 70's was it considered low level? Was the term even in use then? Many popular higher level languages didn't exist until the mid 80's ...
147
votes
6answers
33k views

Why hasn't a faster, “better” language than C come out? [closed]

With all the new "modern" languages out today, how is it that C is still heralded as the fastest and "closest to the machine"? I don't really believe in there ever being only one correct way to do ...
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, ...
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 ...
100
votes
7answers
50k 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 = &...
96
votes
4answers
64k views

How is a Java reference different from a C pointer?

C has pointers and Java has what is called references. They have some things in common in the sense that they all point to something. I know that pointers in C store the addresses they point to. Do ...
95
votes
14answers
182k views

Is the C programming language still used?

I am a C# programmer, and most of my development is for websites along with a few Windows applications. As far as C goes, I haven't used it in a long time, as there was no need to. It came to me as a ...
95
votes
3answers
46k views

Why do programming languages, especially C, use curly braces and not square ones?

The definition of "C-Style language" can practically be simplified down to "uses curly braces ({})." Why do we use that particular character (and why not something more reasonable, like [], which ...
91
votes
15answers
48k views

What makes C so popular in the age of OOP? [closed]

I code a lot in both C and C++, but did not expect C to be the second most popular language, slightly behind Java. TIOBE Programming Community Index I'm curious as to why, in this age of OOP, C is ...
89
votes
16answers
18k views

Do the young minds need to learn the pointer concepts?

Why did the C master Dennis Ritchie introduce pointers in C? And why did the other programming languages like VB.NET or Java or C# eliminate them? I have found some points in Google, and I want to ...
88
votes
6answers
19k views

Why are some C programs written in one huge source file?

For example, the SysInternals tool "FileMon" from the past has a kernel-mode driver whose source code is entirely in one 4,000-line file. The same for the first ever ping program ever written (~2,000 ...
86
votes
19answers
53k views

Why isn't OCaml more popular?

I've always heard that C is the language of choice to use for embedded systems, or anything that needs to run at maximum speed. I never developed a fondness for C, mostly because I don't like pointer ...
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 ...
79
votes
8answers
13k views

Why use trailing newlines instead of leading with printf?

I heard that you should avoid leading newlines when using printf. So that instead of printf("\nHello World!") you should use printf("Hello World!\n") In this particular example above it does not make ...
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
10answers
20k views

Why do C arrays not keep track of their length?

What was the reasoning behind not explicitly storing an array's length with an array in C? The way I see it, there are overwhelming reasons to do so but not very many in support of the standard (C89)....
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 ...
74
votes
14answers
23k views

Are data type declarators like “int” and “char” stored in RAM when a C program executes?

When a C program is running, the data is stored on the heap or the stack. The values are stored in RAM addresses. But what about the type indicators (e.g., int or char)? Are they also stored? ...
73
votes
5answers
22k views

Why are there so few C compilers?

C is one of the most widely-used languages in the world. It accounts for a huge proportion of existing code and continues to be used for a vast amount of new code. It's beloved by its users, it's so ...
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(...
71
votes
5answers
139k views

What should and what shouldn't be in a header file? [closed]

What things should absolutely never be included in a header file? If for example I'm working with a documented industry standard format that has a lot of constants, is it a good practice to define ...
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 ...
67
votes
10answers
38k views

Why has C prevailed over Pascal? [closed]

My understanding is that in the 1980s, and perhaps in the 1990s too, Pascal and C were pretty much head-to-head as production languages. Is the ultimate demise of Pascal only due to Borland's neglect ...
64
votes
11answers
19k views

How can I convince my boss that ANSI C is inadequate for our new project? [closed]

A few months ago, we started developing an app to control an in-house developed test equipment and record a set of measurements. It should have a simple UI, and would likely require threads due to the ...
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 ...
61
votes
11answers
1k views

Have you dealt with space hardening?

I am very eager to study best practices when it comes to space hardening. For instance, I've read (though I can't find the article any longer) that some core parts of the Mars rovers did not use ...
60
votes
8answers
12k views

Why does C provide language 'bindings' where C++ falls short?

I recently was wondering when to use C over C++, and vice versa? Fortunately someone already beat me to it and although it took a while, I was able to digest all the answers and comments to that ...
60
votes
7answers
10k views

Should one check for every little error in C?

As a good programmer one should write robust codes that will handle every single outcome of his program. However, almost all functions from the C library will return 0 or -1 or NULL when there's an ...
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
15answers
71k views

I don't know C. And why should I learn it? [closed]

My first programming language was PHP (gasp). After that I started working with JavaScript. I've recently done work in C#. I've never once looked at low or mid level languages like C. The general ...
58
votes
12answers
23k views

Is this a decent use-case for goto in C?

I really hesitate to ask this, because I don't want to "solicit debate, arguments, polling, or extended discussion" but I'm new to C and want to gain more insight into common patterns used in the ...
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 ...
55
votes
4answers
33k views

When and for what purposes should the const keyword be used in C for variables?

While getting my code reviewed here the issue of using the const keyword came up. I understand that it is used for implementing read-only behaviour on variables. I am confused about what are the ...
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 ...
49
votes
6answers
19k views

Why do many functions that return structures in C, actually return pointers to structures?

What is the advantage of returning a pointer to a structure as opposed to returning the whole structure in the return statement of the function? I am talking about functions like fopen and other low ...
49
votes
5answers
8k views

Is it a good idea to call shell commands from within C?

There's a unix shell command (udevadm info -q path -n /dev/ttyUSB2) that I want to call from a C program. With probably about a week of struggle, I could re-implement it myself, but I don't want to ...
48
votes
4answers
26k views

How could the first C++ compiler be written in C++?

Stroustrup claims that Cfront, the first C++ compiler, was written in C++ (Stroustrup FAQ). However, how is it even possible that the first C++ compiler be written in C++? The code that makes up the ...
48
votes
3answers
181k views

Android development using C and C++ [closed]

I am a C, C++ developer. I am interested in mobile development. I want to know how can I develop Android apps using C and C++, I have read that they are providing a kit for C, C++ developers but it ...
46
votes
16answers
16k views

Languages on a resume: Is it better to put “C/C++” or “C, C++”? [closed]

I'm graduating in a couple of weeks, and my resume (as expected) lists the languages that I've had experience with. Previously I've put "C/C++", however back then I didn't have that much experience ...
46
votes
3answers
11k views

Why do we still grow the stack backwards?

When compiling C code and looking at assembly, it all has the stack grow backwards like this: _main: pushq %rbp movl $5, -4(%rbp) popq %rbp ret -4(%rbp) - does this mean the ...
45
votes
9answers
36k views

Why are pointers not recommended when coding with C++?

I read from somewhere that when using C++ it is recommended not to use pointers. Why is pointers such a bad idea when you are using C++. For C programmers that are used to using pointers, what is the ...
45
votes
2answers
25k views

Are header-only libraries more efficient?

Assumptions One of the advantages of header-only libraries for C++ is that they do not need to be compiled separately. In C and C++ inline makes sense only if the function is defined in a header ...
44
votes
6answers
252k views

Is initializing a char[] with a string literal bad practice?

I was reading a thread titled "strlen vs sizeof" on CodeGuru, and one of the replies states that "it's anyways [sic] bad practice to initialie [sic] a char array with a string literal." Is this true,...
44
votes
2answers
11k views

What is the purpose of NaN boxing?

Reading 21st Century C I arrived at chapter 6 at the section "Marking Exceptional Numeric Values with NaNs", where it explains the use of the bits in the mantissa to store some arbitrary bit patterns, ...